This electronic version (PDF) was scanned by the International Telecommunication Union (ITU) Library & Archives Service from an original paper document in the ITU Library & Archives collections.
La présente version électronique (PDF) a été numérisée par le Service de la bibliothèque et des archives de l'Union internationale des télécommunications (UIT) à partir d'un document papier original des collections de ce service.
Esta versión electrónica (PDF) ha sido escaneada por el Servicio de Biblioteca y Archivos de la Unión Internacional de Telecomunicaciones (UIT) a partir de un documento impreso original de las colecciones del Servicio de Biblioteca y Archivos de la UIT.
(ITU) ﻟﻼﺗﺼﺎﻻﺕ ﺍﻟﺪﻭﻟﻲ ﺍﻻﺗﺤﺎﺩ ﻓﻲ ﻭﺍﻟﻤﺤﻔﻮﻇﺎﺕ ﺍﻟﻤﻜﺘﺒﺔ ﻗﺴﻢ ﺃﺟﺮﺍﻩ ﺍﻟﻀﻮﺋﻲ ﺑﺎﻟﻤﺴﺢ ﺗﺼﻮﻳﺮ ﻧﺘﺎﺝ (PDF) ﺍﻹﻟﻜﺘﺮﻭﻧﻴﺔ ﺍﻟﻨﺴﺨﺔ ﻫﺬﻩ .ﻭﺍﻟﻤﺤﻔﻮﻇﺎﺕ ﺍﻟﻤﻜﺘﺒﺔ ﻗﺴﻢ ﻓﻲ ﺍﻟﻤﺘﻮﻓﺮﺓ ﺍﻟﻮﺛﺎﺋﻖ ﺿﻤﻦ ﺃﺻﻠﻴﺔ ﻭﺭﻗﻴﺔ ﻭﺛﻴﻘﺔ ﻣﻦ ﻧﻘﻼ ً◌
此电子版（PDF版本）由国际电信联盟（ITU）图书馆和档案室利用存于该处的纸质文件扫描提供。
Настоящий электронный вариант (PDF) был подготовлен в библиотечно-архивной службе Международного союза электросвязи путем сканирования исходного документа в бумажной форме из библиотечно-архивной службы МСЭ.
© International Telecommunication Union X V I I A . R DUSSGLDORF 21.5 - 1.6 1990 CCIR XVIIth PLENARY ASSEMBLY DUSSELDORF, 1990
INTERNATIONAL TELECOMMUNICATION UNION
RECOMMENDATIONS OF THE CCIR, 1990 (ALSO RESOLUTIONS AND OPINIONS)
VOLUME VIII
MOBILE, RADIODETERMINATION, AMATEUR AND RELATED SATELLITE SERVICES v. CCIR
1. The International Radio Consultative Committee (CCIR) is the permanent organ of the International Telecommunication Union responsible under the International Telecommunication Convention "... to study technical and operating questions relating specifically to radiocommunications without limit of frequency range, and to issue recommendations on them../' (Inter national Telecommunication Convention, Nairobi 1982, First Part, Chapter I, Art. 11, No. 83)?
2. The objectives of the CCIR are in particular: a) to provide the technical bases for use by administrative radio conferences and radiocommunication services for efficient utilization of the radio-frequency spectrum and the geostationary-satellite orbit, bearing in mind the needs of the various radio services; b) to recommend performance standards for radio systems and technical arrangements which assure their effective and compatible interworking in inter national telecommunications; c) to collect, exchange, analyze and disseminate technical information resulting from studies by the CCIR, and other information available, for the development, planning and operation of radio systems, including any necessary special measures required to facilitate the use of such information in developing countries.
* See also the Constitution of the ITU, Nice, 1989, Chapter 1, Art. 11, No. 84. X V II A.R DUSSEIDORF 21. 5 - 1.6 1990 CCIR XVIIth PLENARY ASSEMBLY DUSSELDORF, 1990
INTERNATIONAL TELECOMMUNICATION UNION
RECOMMENDATIONS OF THE CCIR, 1990 (ALSO RESOLUTIONS AND OPINIONS)
VOLUME VIII
MOBILE, RADIODETERMINATION, AMATEUR AND RELATED SATELLITE SERVICES
CCIR INTERNATIONAL RADIO CONSULTATIVE COMMITTEE
92 - 61- 04241-4 Geneva, 1990 II
PLAN OF VOLUMES I TO XV XVIIth PLENARY ASSEMBLY OF THE CCIR
(Diisseldorf, 1990)
VOLUME I (Recommendations) Spectrum utilization and monitoring Annex to Vol. I (Reports)
VOLUME II (Recommendations) Space research and radioastronomy services Annex to Vol. II (Reports)
VOLUME III (Recommendations) Fixed service at frequencies below about 30 MHz Annex to Vol. I l l (Reports) VOLUME IV-1 (Recommendations) Fixed-satellite service Annex to Vol. IV-1 (Reports) VOLUMES IV/IX-2 (Recommendations) Frequency sharing and coordination between systems in Annex to Vols. IV/IX-2 (Reports) the fixed-satellite'service and radio-relay system
VOLUME V (Recommendations) Propagation in non-ionized media Annex to Vol. V (Reports)
VOLUME VI (Recommendations) Propagation in ionized media Annex to Vol. VI (Reports) VOLUME VII (Recommendations) Standard frequencies and time signals Annex to Vol. VII (Reports) VOLUME VIII (Recommendations) Mobile, radiodetermination, amateur and related satellite services Annex 1 to Vol. VIII (Reports) Land mobile service — Amateur service — Amateur satellite service Annex 2 to Vol. VIII (Reports) Maritime mobile service Annex 3 to Vol. VIII (Reports) Mobile satelllite services (aeronautical, land, maritime, mobile and radiodetermination) — Aeronautical mobile service VOLUME IX-1 (Recommendations) Fixed service using radio-relay systems Annex to Vol. IX-1 (Reports) VOLUME X-l (Recommendations) Broadcasting service (sound) Annex to Vol. X-l (Reports) VOLUMES X/XI-2 (Recommendations) Broadcasting-satellite service (sound and television) Annex to Vols. X/XI-2 (Reports) VOLUMES X/XI-3 (Recommendations) Sound and television recording Annex to Vols. X/XI-3 (Reports) VOLUME XI-1 (Recommendations) Broadcasting service (television) Annex to Vol. XI-1 (Reports) VOLUME XII (Recommendations) Television and sound transmission (CMTT) Annex to Vol. X II (Reports) VOLUME XIII (Recommendations) Vocabulary (CCV) VOLUME XIV Administrative texts of the CCIR VOLUME XV-1 (Questions) Study Groups 1, 12, 5, 6, 7 VOLUME XV-2 (Questions) Study Group 8 VOLUME XV-3 (Questions) Study Groups 10, 11, CMTT VOLUME XV-4 (Questions) Study Groups 4, 9
All references within the texts to CCIR Recommendations, Reports, Resolutions, Opinions, Decisions and Questions refer to the 1990 edition, unless otherwise noted; i.e., only the basic number is shown.
© IT U 1990 Printed in Switzerland Ill
DISTRIBUTION OF TEXTS OF THE XVIIth PLENARY ASSEMBLY OF THE CCIR IN VOLUMES I TO XV
Volumes and Annexes I to XV* XVIIth Plenary Assembly, contain all the valid texts of the CCIR and succeed those of the XVIth Plenary Assembly, Dubrovnik, 1986.
1. Recommendations, Resolutions, Opinions are given in Volumes I-XIV and Reports,. Decisions in the Annexes to Volumes I-XII.
When a Recommendation, Report, Resolution or Opinion is modified, it retains its number to which is added a dash and a figure indicating how many revisions have been made. Within the text of Recommendations, Reports, Resolutions, Opinions and Decisions, however, reference is made only to the basic number (for example Recommendation 253). Such a reference should be interpreted as a reference to the latest version of the text, unless otherwise indicated. The tables which follow show only the original numbering of the current texts, without any indication of successive modifications that may have occurred. For further information about this numbering scheme, please refer to Volume XIV.
1.2 Recommendations
N um ber V olum e N um ber V olum e N um ber V olum e
48 X -l 368-370 V 479 II 80 X -l 371-373 VI 480 III 106 III 374-376 VII 481-484 IV-1 139 X -l 377, 378 I 485, 486 VII 162 III 380-393 IX-1 487-493 V III-2 182 I 395-405 IX-1 494 VIII-1 2 1 5 ,2 1 6 X -l 406 IV /IX -2 496 V III-2 218, 219 V III-2 4 0 7 /4 0 8 X /X I -3 497 IX-1 239 I 4 1 1 ,4 1 2 X -l 498 X -l 240 III 415 X -l 500 XI-1 246 III 417 XI-1 501 X /X I -3 257 V III-2 .419 XI-1 502, 503 XII 265 X /X I -3 428 VIII-2 505 XII 266 XI-1 430, 431 XIII 508 . I 268 IX-1 433 I 509, 510 II 270 IX-1 434, 435 VI 513-517 II 275, 276 IX-1 436 III 518-520 III 283 IX-1 439 VIII-2 521-524 IV-1 290 IX-1 441 V III-3 525-530 V 302 IX-1 443 I 531-534 VI 305, 306 IX-1 444 IX-1 535-538 VII 3 1 0 ,3 1 1 V 446 IV -1 539 VIII-1 313 VI 450 X -l 540-542 V III-2 314 II 452, 453 V 546-550 V III-3 326 I 454-456 III 552, 553 V III-3 328, 329 I 457, 458 VII 555-557 IX-1 331, 332 I 460 VII 558 IV /IX -2 335, 336 III 461 XIII 559-562 X -l 337 I 463 IX-1 565 XI-1 338, 339 III 464-466 IV-1 566 X /X I -2 341 V 467, 468 X -l - 567-572 XII 342-349 III 469 X /X I -3 .5 7 3 , 574 XIII 352-354 IV -1 470-472 XI-1 575 I 355-359 IV /IX -2 473, 474 XII 576-578 II 362-364 II 475, 476 VIII-2 579, 580 IV-1 367 II 478 VIII-1 581 V IV
1.2 Recommendations (cont.)
N um ber V olum e N um ber V olum e N um ber V olum e
582, 583 VII 625-631' V III-2 676-682 V 584 VIII-1 632, 633 VIII-3 683, 684 VI 585-589 VIII-2 634-637 IX 685, 686 VII 591 VIII-3 638-641 X -l 687 VIII-1 592-596 IX-1 642 X -l . 688-693 V III-2 597-599 X -l 643, 644 X -l 694 VIII-3 600 X /X I -2 645 X -l + X II 695-701 IX-1 601 XI-1 646, 647 X -l 702-704 X -l 602 X /X I -3 648, 649 X /X I -3 705 X -l
1.3 Reports
N um ber V olum e N um ber V olum e N um ber V olum e
19 III 319 VIII-1 472 X -l 122 XI-1 322 VI ( ’) 473 X /X I -2 137 IX-1 324 I 476 XI-1 181 I 327 III 478 XI-1 183 III 336* V 481-485 XI-1 195 III 338 V 488 XII 197 III 340 VIO 491 XII 203 III 342 VI 493 XII 208 IV-1 345 III 496, 497 XII 209 IV /IX -2 347 III 499 VIII-1 212 IV-1 349 III 500, 501 V III-2 214 IV-1 354-357 III 509 V III-3 - 215 X /X I -2 358 VIII-1 516 X -l 222 II 363, 364 VII 518 VII 224 II 371, 372 I 521, 522 I 226 II 375, 376 IX-1 525, 526 I 227* V 378-380 IX-1 528 I 228, 229 V 382 IV /IX -2 533 I 238, 239 V 384 IV-1 535, 536 II 249-251 VI 386-388 IV /IX -2 538 II 252 V I 0 ) 390, 391 IV-1 540, 541 II 253-255 • VI 393 IV /IX -2 543 II 258-260 VI 395 II 546 II 262, 263 VI 401 X -l 548 II 265, 266 VI 404 XI-1 549-551 III 267 VII 409 XI-1 552-558 IV-1 270, 271 VII 411, 412 XII 560, 561 IV-1 272, 273 I 430-432 VI 562-565 V 275-277 I 435-437 III 567 V 279 I 439 VII 569 V 285 IX-1 443 IX-1 571 VI 287* IX-1 445 IX-1 574, 575 VI 289* IX -1 448, 449 IV /IX -2 576-580 VII 292 X -l 451 IV-1 584, 585 V III-2 294 X /X I-3 453-455 IV-1 588 V III-2 300 X -l 456 II 607 IX-1 302-304 X -l 458 X -l 610* IX-1 311-313 XI-1 463, 464 X -l 612-615 IX-1 314 XII 468, 469 X /X I -3 622 X /X I -3
* Not reprinted, see Dubrovnik, 1986. (') Published, separately. V
1.3 Reports (cont.)
N um ber V olum e N um ber V olum e N um ber V olum e
624-626 XI-1 790-793 IV /IX -2 972-979 I 628, 629 XI-1 795 X -l 980-985 II 630 X /X I -3 798, 799 X -l 987, 988 II 631-634 X /X I -2 801, 802 XI-1 989-996 III 635-637 XII 803 X /X I -3 997-1004 IV-1 639 XII 804, 805 XI-1 1005, 1006 IV /IX -2 642, 643 XII 807-812 X /X I -2 1007-1010 V 646-648 XII 814 X /X I -2 1011, 1012 VI 651 I 815, 816 XII 1016, 1017 VII 654-656 I 818-823 XII 1018-1025 V III-1 659 I 826-842 I 1026-1033 V III-2 662-668 I 843-854 II 1035-1039 V III-2 670, 671 I 857 III 1041-1044 V III-2 672-674 II 859-865 III 1045 V III-3 676-680 II 867-870 IV-1 1047-1051 V III-3 682-685 II 872-875 IV-1 1052-1057 IX-1 687 II 876, 877 IV /IX -2 1058-1061 X -l 692-697 II 879, 880 V 1063-1072 X -l 699, 700 II 882-885 V 1073-1076 X /X I -2 701-704 III 886-895 VI 1077-1089 XI-1 706 IV-1 896-898 VII 1090-1092 XII 709 IV /IX -2 899-904 VIII-1 1094-1096 XII, 710 IV-1 908 V III-2 1097-1118 I 712, 713 IV-1 9 1 0 ,9 1 1 V III-2 1119-1126 II 714-724 V 913-915 V III-2 1127-1133 III 725-729 VI 917-923 VIII-3 1134-1141 IV-1 731, 732 VII 925-927 VIII-3 1142, 1143 IV /IX -2 735, 736 VII 929 VIII-3 O 1144-1148 V 738 VII 930-932 IX-1 1149-1151 VI 739-742 VIII-1 • 934 IX-1 1152 VII 743, 744 V III-2 936-938 IX-1 1153-1157 VIII-1 748, 749 V III-2 940-942 IX-1 1158-1168 V III-2 751 VIII-3 943-947 X -l 1169-1186 V III-3 760-764 V lII-3 950 X /X I -3 1187-1197 IX-1 766 VIII-3 951-955 X /X I -2 1198 X -l (') 770-773 VIII-3 956 XI-1 1199-1204 X -l 774, 775 V III-2 958, 959 XI-1 1205-1226 XI-1 778 VIII-1 961, 962 XI-1 1227, 1228 X /X I -2 780* IX-1 963, 964 X /X I -3 1229-1233 X /X I -3 781-789 IX-1 965-970 XII 1234-1241 XII
* Not reprinted, see Dubrovnik, 1986. (') Published separately.
1.3.1 Note concerning Reports The individual footnote “Adopted unanimously” has been dropped from each Report. Reports in Annexes to Volumes have been adopted unanimously except in cases where reservations have been made which will appear as individual footnotes.
1.4 Resolutions
N um ber V olum e N um ber V olum e N um ber V olum e
4 VI 62 I 86, 87 XIV 14 VII 63 VI 88 I 15 I 64 X -l 89 XIII 20 VIII-1 71 I 95 XIV 23 XIII 72, 73 V 97-109 XIV 24 XIV 74 VI 110 I 33 XIV 76 ' X -l 111, 112 VI 39 XIV .78 XIII 113, 114 XIII 61 XIV 79-83 XIV VI
1.5 Opinions
N um ber V olum e N um ber V olum e N um ber V olum e
2 I 45- VI 7 3 ' . VIII-1 11 I 49 VIII-1 74 X-l + X/XI-3 14 IX-1 50 IX-1 • 75 XI-1 + X/XI-3 15 X -l ' 51 X -l 77 XIV 16 X /X I -3 56 IV-1 79-81 XIV 22, 23 VI 59 X -l 82- VI 26-28 VII 63 XIV 83 XI-1 32 I 64 I 84 XIV 35 I 65 XIV 85 VI 38 XI-1 66 III 87, 88 XIV 40 XI-1 67-69 VI 89 IX-1 42 VIII-1 71-72 VII 90 X /X I -3 43 V III-2
1.6 Decisions
N um ber V olum e N um ber V olum e N um ber V olum e
2 IV-1 60 XI-1 87 IV /IX -2 4, 5 V 63 III 88, 89 IX-1 6 VI 64 IV-1 90, 91 XI-1 9 VI 65 VII 93 X /X I -2 11 VI 67, 68 XII 94 X -l X-l + XI-1 + 69 VIII-1 95 X-l -I- XI-1 18 XII 70 iv-i 96, 97 X -l 27 I 71 VIII-3 98 X -l + X II ' 4 2 XI-1 72 X -l + XI-1 99 X -l 43 X /X I -2 IV-1 + X-l + 100 I 76 51 X /X I -2 XI-1 + X II 101 II 53, 54 I 77 XII 102 V 56 I 78, 79 X -l 103 VIII-3 57 VI 80 XI-1 105 XIV 58 XI-1 81 VIII-3 106 XI-1 59 X /X I -3 83-86 VI
2. Questions (Vols. XV-1, XV-2, XV-3, XV-4)
2.1 Numbering of texts
Questions are numbered in a different series for each Study Group: where applicable a dash and a figure added after the number of the Question indicate successive modifications. The number of a Question is completed by an Arabic figure indicating the relevant Study Group. For example: — Question 1/10 would indicate a Question of Study Group 10 with its text in the original state; — Question 1-1/10 would indicate a Question of Study Group 10, whose text has been once modified from the original; Question 1-2/10 would be a Question of Study Group 10, whose text has had two successive modifications. Note — The numbers of the Questions of Study Groups 7, 9 and 12 start from 101. In the case of Study Groups 7 and 9, this was caused by the need to merge the Questions of former Study Groups 2 and 7 and Study Groups 3 and 9, respectively. In the case of Study Group 12, the renumbering was due to the requirement to transfer Questions from other Study Groups.
2.2 Assignment o f Questions
In the plan shown on page II, the relevant Volume XV in which Questions of each Study Group can be found is indicated. A summary table of all Questions* with their titles, former and new numbers is to be found in Volume XIV. VII
2.3 References to Questions
As detailed in Resolution 109, the Plenary Assembly approved the Questions and assigned them to the Study Groups for consideration. The Plenary Assembly also decided to discontinue Study Programmes. Resolution 109 therefore identifies those Study Programmes which were approved for conversion into new Questions or for amalgamation with existing Questions. It should be noted that references to Questions and Study Programmes contained in the texts of Recommendations and Reports of Volumes I to XIII are still those which were in force during the study period 1986-1990. Where appropriate, the Questions give references to the former Study Programmes or Questions from which they have been derived. New numbers have been given to those Questions which have been derived from Study Programmes or transferred to a different Study Group. PAGE INTENTIONALLY LEFT BLANK
PAGE LAISSEE EN BLANC INTENTIONNELLEMENT IX
VOLUME VIII
MOBILE, RADIODETERMINATION, AMATEUR AND RELATED SATELLITE SERVICES
(Study Group 8)
TABLE OF CONTENTS
Page Plan of Volumes I to XV, XVIIth Plenary Assembly of the C C IR ...... II Distribution of texts of the XVIIth Plenary Assembly of the CCIR in Volumes I to X V . . Ill Table of contents ...... IX Numerical index of texts ...... XIII Terms of reference of Study Group 8 and Introduction by the Chairman of Study Group 8 ...... XV
Section 8A — Land mobile service and related subjects
Rec. 494 Technical characteristics of single-sideband equipment in the MF and HF land mobile radiotelephone service ...... 1 Rec. 478-4 Technical characteristics of equipment and principles governing the allocation of frequency channels between 25 and 1000 MHz for the land mobile service ...... 3 Rec. 539-2 Technical and operational characteristics of future international radio-paging systems . 7 Rec. 584-1 Standard codes and formats for international radio paging ...... 11 Rec. 622 Technical and operational characteristics of analogue cellular systems for public land mobile telephone use ...... 16 Rec. 687 Future Public Land Mobile Telecommunication Systems (FPLMTS) ...... 19 Rec. 623 Data transmission bit rates and modulation techniques in the land mobile service .... 30 Rec. 624 Public land mobile communication systems location registration 31
Section 8B — Maritime mobile service; telegraphy and related subjects
Rec. 585-2 Assignment and use of maritime mobile service identities ...... 37 Rec. 218-2 Prevention of interference to radio reception on board s h i p s ...... 40 Rec. 625-1 Direct-printing telegraph equipment employing automatic identification in the maritime mobile service ...... 42 Rec. 476-4 Direct-printing telegraph equipment in the maritime mobile se rv ic e ...... 97 Rec. 490 The introduction of direct-printing telegraph equipment in the maritime mobile service. Equivalence o f term s...... 107 X
Page Rec. 491-1 Translation between an identity number and identities for direct-printing telegraphy in the maritime mobile service...... 108 Rec. 492-4 Operational procedures for the use of direct-printing telegraph equipment in the maritime mobile service...... 112 Rec. 540-2 Operational and technical characteristics for an automated direct-printing telegraph system for promulgation of navigational and meteorological warnings and urgent information to ships ...... 119 Rec. 688 Technical characteristics for a high frequency direct-printing telegraph system for promulgation of high seas and NAVTEX-type maritime safety information ...... 122 Rec. 692 Narrow-band direct-printing telegraph equipment using a single-frequency channel . . . 123 Rec. 493-4 Digital selective-calling system for use in the maritime mobile service ...... 124 Rec. 541-3 Operational procedures for the use of digital selective-calling (DSC) equipment in the maritime mobile service...... 150 Rec. 626 Evaluation of the quality of digital channels in the maritime mobile service ...... 163 Rec. 627 Technical characteristics for HF maritime radio equipment using narrow-band phase- shift keying (NBPSK) telegraphy ...... 164
Section 8C — Maritime mobile service; telephony and related subjects
Rec. 219-1 Alarm signal for use on the maritime radiotelephony distress frequency of 2182 kHz . . 167 Rec. 257-2 Selective-calling system for use in the maritime mobile se rv ic e...... 169 Rec. 428-3 Direction-finding and/or homing in the 2 MHz band on board ships ...... 173 Rec. 488-1 Equivalent powers of double-sideband and single-sideband radiotelephone emissions in the maritime mobile service...... 176 Rec. 489-1 Technical characteristics of VHF radiotelephone equipment operating in the maritime mobile service in channels spaced by 25 kHz ...... • • ...... 178 Rec. 475-1 Improvements in the performance of radiotelephone circuits in the MF and HF maritime mobile b an d s ...... 180 Rec. 542-1 On-board communications by means of portable radiotelephone equipment ...... 197 Rec. 586-1 Automated VHF/UHF maritime mobile telephone system ...... 198 Rec. 587-1 Coast station identities and initiation of location registration in an automated VHF/UHF maritime mobile telephone system ...... 242 Rec. 689 Operational procedures for an international maritime VHF radiotelephone system with automatic facilities based on DSC signalling format ...... 243
Section 8D - Radiodetermination, global maritime distress and safety system and related subjects
Rec. 628-1 Technical characteristics for search and rescue radar transponders...... 251 Rec. 629 Use for the radionavigation service of the frequency bands 2900-3100 MHz, 5470-5650 MHz, 9200-9300 MHz, 9300-9500 MHz and 9500-9800 M H z ...... 253 Rec. 439-3 Emergency position-indicating radio beacons operating at the frequency 2182 kHz . . . 255 Rec. 690 Transmission characteristics of emergency position-indicating radio beacons (EPIRBs) operating on carrier frequencies of 121.5 MHz and 243 MHz ...... 257 Rec. 693 Technical characteristics of VHF emergency position-indicating radio beacons using digital selective calling (DSC VHF E P IR B )...... 258 XI
Page Rec. 487 Use of radio-beacon stations for communications ...... 260 Rec. 588 Characteristics of maritime radio beacons (Region 1)...... 261 Rec. 630 Main characteristics of two frequency shipborne interrogator transponders (SIT) .... 262 Rec. 589-1 Interference to radionavigation services from other services in the bands between 70 kHz and 130 kHz . . . . , 265 Rec. 631 Use of hyperbolic maritime radionavigation systems in the band 283.5-315 kHz ..... 266 Rec. 691 Technical characteristics and compatibility criteria of maritime radiolocation systems operating in the medium frequency band and using spread-spectrum techniques...... 267 Rec. 496-2 Limits of power flux-density of radionavigation transmitters to protect space station receivers in the fixed-satellite service in the 14 GHz b a n d ...... 268
Section 8E — Definitions (No texts)
Section 8F — Frequencies, orbits and systems
Rec. 546-2 Hypothetical telephone reference circuit in the aeronautical, land and maritime mobile- satellite services ...... 269
Section 8G — Availability, performance objectives and interworking with terrestrial networks
Rec. 547 Noise objectives in the hypothetical reference circuit for systems in the maritime mobile-satellite service . : . . 273 Rec. 549-1 Side tone reference equivalent of handset used on board a ship in the maritime mobile-satellite service and in automated VHF/UHF maritime mobile radiotelephone systems ...... 275 Rec. 552 Quality objectives for 50-baud start-stop telegraph transmission in the maritime mobile- satellite service...... 276
Section 8H — Efficient use o f the radio spectrum characteristics and sharing o f frequency resources
There are no Recommendations in this Section.
Section 81 — Technical and operating characteristics o f mobile satellite services
Rec. 548 Overall transmission characteristics of telephone circuits in the maritime mobile- satellite service ...... 279 Rec. 550-1 Use of echo suppressors in the maritime mobile-satellite service ...... 282 Rec. 553 Interface requirements for 50-baud start-stop telegraph transmission in the maritime mobile-satellite service...... 283 Rec. 694 Reference radiation pattern for ship earth station a n te n n a s ...... 285
Section 8J — Technical and operating characteristics o f radiocommunications using satellite distress and safety operation and o f radio determination satellite services
Rec. 632-1 Transmission characteristics of a satellite emergency position-indicating radiobeacon (satellite EPIRB) system operating through geostationary satellites in the 1.6 GHz band 287 Rec. 633-1 Transmission characteristics of a satellite emergency position-indicating radiobeacon (satellite EPIRB) system operating through a.low polar-orbiting satellite system in the 406 MHz b a n d ...... '...... 294 XII
Page
Section 8K — Aeronautical mobile service (terrestrial)
Rec. 441-1 Signal-to-interference ratios and minimum field strengths required in the aeronautical mobile (R) service above 30 MHz ...... 311 Rec. 591-1 Compatibility between the broadcasting service in the band of about 87-108 MHz and the aeronautical services in the band 108-136 MHz ...... 312
Section 8L — Amateur service; amateur satellite service
There are no Recommendations in this section
Resolutions and Opinions Resolution 20-5 Characteristics of equipment and principles governing the allocation of frequency channels between 25 and 3000 MHz in the land mobile service...... 315 Opinion 42-2 Methods of measurement of technical characteristics of equipment for the land mobile service between 25 and 3000 MHz ...... 316 Opinion 43-2 Self-supporting antennas for use on board ships .....'...... 317 Opinion 49-1 Method of measurement of man-made noise in the various mobile services ...... 318 Opinion 73 Interference due to man-made noise in the various mobile services...... 319 XIII
NUMERICAL INDEX OF TEXTS
Page
SECTION 8A: Land mobile service and related subjects ...... 1 SECTION 8B: Maritime mobile service; telegraphy and related subjects...... 37 SECTION 8C: Maritime mobile service; telephony and related subjects ...... 167 SECTION 8D: Radiodetermination, global maritime distress and safety system.and related subjects .... 251 SECTION 8E: Definitions...... 268 SECTION 8F: Frequencies, orbits and systems ...... 269 SECTION 8G: Availability, performance objectives and inerworking with terrestrial networks...... 273 SECTION 8H: Efficient use of the radio spectrum characteristics and sharing of frequency resources .... 277 SECTION 81: Technical and operating characteristics of mobile satellite services...... 279 SECTION 8J: Technical and operating characteristics of radiocommunicztions using satellite distress and safety operation and of radio determination satellite services...... 287 SECTION 8K: Aeronautical mobile service (terrestrial) ...... 311 SECTION 8L: Amateur service; amateur satellite service ...... 313 RESOLUTIONS AND OPINIONS ...... 315
RECOMMENDATIONS Section Page RECOMMENDATIONS Section Page
Recommendation 218-2 8B 40 Recommendation 586—1 8C 198 Recommendation 219-1 8C 167 Recommendation 587-1 8C 242 Recommendation 257-2 8C 169 Recommendation 588 8D 261 Recommendation 428-3 8C 173 Recommendation 589-1 8D 265 Recommendation 439-3 8D 255 Recommendation 591-1 8K 312 Recommendation 441—1 8K 311 Recommendation 622 8A 16 Recommendation 475-1 8C 180 Recommendation 623 8A 30 Recommendation 476-4 8B ' 97 Recommendation 624 8A 31 Recommendation 478-4 8A 3 Recommendation 625-1 8B 42 Recommendation 487 8D 260 Recommendation 626 8B 163 Recommendation 488-1 8C 176 Recommendation 627 8B 164 Recommendation 489-1 8C 178 Recommendation 628-1 8D 251 Recommendation 629 Recommendation 490 8B 107 8D 253 Recommendation 630 8D 262 Recommendation 491-1 8B 108 Recommendation 631 8D 266 Recommendation 492-4 8B 112 Recommendation 632-1 8J 287 Recommendation 493-4 8B 124 Recommendation 633—1 8J 294 Recommendation 494 8A 1 Recommendation 687 8A 19 Recommendation 496-2 8D 268 Recommendation 688 8B 122 Recommendation 539-2 8A 7 Recommendation 689 8C 243 Recommendation 540-2 8B 119 Recommendation 690 8D 257 Recommendation 541-3 8B 150 Recommendation 691 8 D 267 Recommendation 542-1 8C 197 Recommendation 692 8B 123 Recommendation 546-2 8F 269. Recommendation 693 8D 258 Recommendation 547 8G 273 Recommendation 694 81 285 Recommendation 548 81 279 Recommendation 549-1 8G 275 RESOLUTIONS AND OPINIONS
Recommendation 550-1 81 282 Resolution 20-5 315 Recommendation 552 8G 276 Opinion 42-2 316 Recommendation 553 81 283 Opinion 43-2 317 Recommendation 584-1 8A 11 Opinion 49-1 318 Recommendation 585-2 8B 37 O pinion 73 319 PAGE INTENTIONALLY LEFT BLANK
PAGE LAISSEE EN BLANC INTENTIONNELLEMENT XV
STUDY GROUP 8
MOBILE SERVICES
Terms o f reference:
To study the technical and operating aspects of systems in:
1. all mobile services and all mobile-satellite services;
2. the radiodetermination services and the radiodetermination-satellite services, and;
3. the amateur service and amateur-satellite service.
1986-1990 Chairman: E. GEORGE (Germany (Federal Republic of)) Vice-Chairmen: Y. HIRATA (Japan) J. KARJALAINEN (Finland) R. C. McINTYRE (United States of America) O. VILLANYI (Hungarian People’s Republic)
As from the next study period, in conformity with Resolution 61 adopted at the XVIIth Plenary Assembly, Dusseldorf (May-June 1990), the scope of the work which will be undertaken and the names of the Chairman and Vice-Chairmen concerned are given below:
STUDY GROUP 8
MOBILE, RADIODETERMINATION AND AMATEUR SERVICES
Scope:
Technical and operating aspects of systems for the mobile, radiodetermination and amateur services, including related satellite services.
1990-1994 Chairman: E. GEORGE (Germany (Federal Republic of)) Vice-Chairmen: Y. HIRATA (Japan) O. VILLANYI (Hungary (Republic of)) R. C. McINTYRE (United States of America) A. DHARAB (Saudi Arabia (Kingdom of)) XVI
INTRODUCTION BY THE CHAIRMAN OF STUDY GROUP 8, 1986-1990
1. Introduction
1.1 CCIR Study Group S studies technical and operational aspects relating to all the mobile and mobile- satellite services, the radiodetermination and radiodetermination satellite services and the amateur and amateur- satellite services. 1.2 The period between the XVIth and XVIIth Plenary Assemblies has been extremely busy, not only with the preparation of Recommendations and Reports in response to current questions, but also the preparation of the technical bases relating to Study Group 8 issues for two World Administrative Radio Conferences. 1.3 Mobile telecommunications are rapidly growing, and there is an ever increasing demand for these services. New areas of study have been identified where immediate answers are required. Study Group 8 has again given proof that it is capable of reacting immediately and coping with these challenging tasks. 1.4 Cooperation with the International Maritime Organization (IMO) and the International Civil Aviation Organization (ICAO) is contihuing to be extremely fruitful. Liaison with the International Electrotechnical Committee (IEC) has been intensified. 1.5 Although the scope of studies is large and steadily expanding, no practical difficulties have been encountered with the execution of the work. The decision taken at the XVIth Plenary Assembly not to split the work of Study Group 8 into two or more Study Groups has proved to be right, because otherwise CCIR studies in these services would be seriously hampered. All mobile services and .radiodetermination services, including satellite techniques, are so closely related to each other that any separation would render studies in these services much more difficult. By the use of Interim Working Parties to carry out in-depth studies where urgent answers are required and by sub-dividing the work at Interim and Final Meetings into suitable working groups, Study Group 8 has succeeded in meeting all its expectations. The present organization works efficiently and should not be changed. 1.6 During the past study period most of the texts concerning the Global Maritime Distress and Safety System have been finalized, e.g., digital selective calling, narrow-band direct-printing, satellite EPIRBs and VHF EPIRB. 1.7 The following table gives a summary of Study Group 8 activities for the study period 1986-1990.
New Modified No change Suppressed
Recommendations 8 12 36 _ Reports 34 49 36 10 Questions and Study 18 28 30 21 Programmes
2. Interim Working Parties and Joint Interim Working Parties with Study Group 8 involvement
Interim Working Parties and Joint Interim Working Parties created at the Final Meeting for the preparation of the technical bases for WARC-92 are treated in § 4.
2,1 Interim Working Party 8 /7 (Decision 32, deleted at the Interim Meeting)
IWP 8/7, established in 1978 to continue studies on technical and operating characteristics of systems in the maritime mobile-satellite service, previously begun in IWPs 8/1 and 8/4, held its 7th meeting from ' 13-20 May 1986 under the chairmanship of Dr. Y. Hirata (Japan). It developed a number of revised and new texts concerning the subject matter and identified possible areas for future studies, e.g., systems for aeronautical communications, which required a widening of its terms of reference. At the Interim Meeting it was decided to follow in principle this course of action. IWP 8/7 was dissolved and a new IWP was created in order to continue the studies previously undertaken in IWP 8/7 and to tackle new areas (see § 2.3). XVII
2.2 Interim Working Party 8/13 (Decision 81)
IWP 8/13, established at the Final Meeting of Study Group 8 (study period 1982-1986) in order to expedite studies on future public land mobile telecommunication systems (FPLMTS), has been very active since its creation and has held so far Five meetings under the chairmanship of Mr. M. Callendar (Canada), the last meeting being held from 26 May to 8 June 1989. The results of the IWP work are summarized in § 5.2. Due to the many questions concerning interconnection with the public switched telecommunication network involved in the work of the IWP, close cooperation is maintained with the relevant Study Groups of the CCITT. Work will continue and Decision 69 was modified to provide for an efficient CCIR preparation of the technical bases for WARC-92 (see also § 4).
2.3 Interim Working Party 8/14 (Decision 81)
IWP 8/14 was established at the Interim Meeting of Study Group 8 to study technical and operating characteristics necessary for compatibility, interoperability and the required performance levels for systems in the . mobile satellite services: Special attention is also paid to public correspondence with aircraft, both by terrestrial and satellite means. It replaces IWP 8/7, which had similar, but more restricted terms of reference. The IWP has been very active since its creation under its chairman Dr. Y. Hirata (Japan). Two meetings have been held, the second from 15-24 May 1989. The IWP identified a wide range of areas for future studies in view of the fact that all mobile-satellite services will experience tremendous expansion in the future. The results of the work are summarized in § 5.4. IWP 8/14 is similarly maintaining close cooperation with CCITT. Decision 81 was amended at the Final Meeting to provide for an efficient CCIR preparation of the technical bases for WARC-92 (see also § 4),
2.4 Joint Interim Working Party 8-10/1 (Decision 71)
JIWP 8-10/1, established to carry out studies on the compatibility between the aeronautical radionaviga tion service in the band 108-117.975 MHz, the aeronautical mobile (R) service in the band 117.975-137 MHz and the FM sound broadcasting stations in the band about 87-108 MHz, held its third meeting from 1-10 August 1988 under the chairmanship of Mr. J. Karjalainen (Finland). The results of the work of the JIWP are summarized in §5.5.1. The JIWP expressed the opinion that it should continue its work due to the many questions still unresolved. This opinion was confirmed at the Final Meeting of the Study Group. Items for further study are listed in Report 929.
2.5 Joint Interim Working Party ORB(2)/SG4
The CCIR Report to the Second Session of the World Administrative Radio Conference on the Use of the Geostationary-Satellite Orbit and the Planning of the Space Services Utilizing it, prepared by JIWP ORB(2), was very useful at the conference. The Study Group 8 contribution has been provided by IWP 8/7. No particular Study Group 8 actions are required as a result of the conference.
2.6 Joint Interim Working Party 10-3-8/1
JIWP 10-3-8/1 was reconvened under the provision of Resolution 91 of the XVIth CCIR Plenary Assembly to carry out the studies requested by the First Session of the Regional Administrative Radio Conference to Establish a Plan for the Broadcasting Service in the band 1605-1705 kHz in Region 2 (BC-R2(1)). The JIWP met from 13-15 May 1987 and prepared a report for submission to the Second Session of BC-R2, which was held from 23 May to 8 June 1988. Since this report had to be submitted to administrations well before the Interim Meeting of Study Group 8, the Chairman, Study Group 8, on behalf of the Study Group, commented and, subject to the acceptance of the comments, approved the report. The JIWP was then dissolved.
2.7 Joint Interim Working Party AFBC(2) (Decision 75)
2.1 A JIWP AFBC(2), joining Study Groups 1, 5, 8, 9, 10 and 11, was established following a request by the First Session (1986) of the Regional Administrative Radio Conference for the Planning of VHF/UHF Television Broadcasting in the African Broadcasting Area and Neighbouring Countries. Part of the work of the JIWP concerned the sharing between mobile and broadcasting services. The JIWP prepared, after two meetings, the CCIR Report to the Second Session of RARC AFBC, which was approved by the Chairman of Study Group 8 on behalf of the Study Group. XVIII
2.7.2 In preparation for the second JIWP meeting, the JIWP Chairman had requested the Chairman, Study Group 8, to verify certain values of minimum field strength to be protected contained in Report 1098 and based on Report 358 (Protection ratios and minimum field strengths required in the mobile services) and to provide advice concerning minimum field strengths, protection ratios and the signal quality grade for which protection is required. The advice — although incomplete — was given, but this has been a very difficult task because it became evident that Report 358, which is the only relevant basic Study Group 8 text, is incomplete, and is partly inconsistent and lacking in clarity. It is therefore essential that every effort should be made in the coming study period to update and re-write Report 358 in order to make its application easier and to make it respond more to practical needs. An attempt should also be made - to extract those elements which are mature enough to form the basis for a draft Recommendation. This matter is the more important because the study of sharing questions is dependent to a great extent on this information.
2.8 Joint Interim Working Party VHF/UHF sharing Regions 3, 1/SG I (Resolution 94)
The JIWP on sharing in the VHF and UHF bands in Region 3 was established under the direction of Study Group 1 to fulfill the commitments of the CCIR to a proposed future Region 3 conference on sharing of frequency allocations between fixed, broadcasting and mobile services within the Region. In the period between the Interim and Final Meetings of Study Group 8 no JIWP meeting was held. For consideration at the Final Meeting of Study Group 1, the JIWP prepared a draft CCIR report to the conference which states that “sharing issues within Region 3 are likely to be dominated by problems of sharing between the television services of various countries or areas rather than sharing between different services”. Therefore the continued involvement of Study Group 8 concerning this issue is considered to be less urgent. After the Final Study Group Meetings it was decided to suspend the work of the JIWP because the date of the conference has not yet been decided.
2.9 Joint Interim Working Party “Coordination Area" (Decision 87)
Study Group 8 decided at its Final Meeting that, provided the review of Appendix 28 to the Radio Regulations is not covered by the agenda of WARC-92, it will join JIWP “Coordination Area”, established at the Final Study Group Meetings by Study Groups 2, 4, 5, 8, 9, 10 and 11 in order to undertake a comprehensive revision of CCIR texts relevant to Appendix 28 (Method for the Determination of the Coordination Area around an Earth Station in Frequency Bands Between 1 and 40 GHz Shared Between Space and Terrestrial Radiocommu nication Services). .
3. Special Meeting of Study Group 8 to Prepare the Technical Bases for the World Administrative Radio Conference for the Mobile Services (WARC MOB-87)
3.1 In response to Resolution No. 202 of WARC-79, Resolution No. 933 of the Administrative Council and CCIR Resolution 92 Study Group 8 held a Special Meeting from 30 June^ to 11 July 1986 to prepare the technical and operational bases for WARC MOB-87. The large attendance at the meeting provided evidence of the high importance that administrations and other participants in the work of CCIR attribute to CCIR in preparing the technical and operational bases for administrative conferences of the Union.
3.2 Despite the very limited time of only two weeks, Study Group 8 established, on behalf of CCIR, a comprehensive report of some 160 pages covering all conference agenda items where technical or operational questions were involved. It was based on the texts of the XVIth CCIR Plenary Assembly and additional contributions from administrations and other participants in the Special Meeting. It was prepared in a form designed primarily to assist administrations in preparing proposals for the conference. It also aimed to serve, at the conference, as a ready reference on the technical and operational topics relevant to each agenda item.
3.3 The Report of the Special Meeting of Study Group 8, issued as a conference document, proved to be of the utmost use both before and at the conference. The conference accepted the technical and operational advice provided by CCIR.
3.4 The conference adopted a number of new or revised Resolutions and Recommendations in which the CCIR is requested to undertake or to continue studies. The majority of these studies is already covered by existing Questions or Study Programmes of Study Group 8. A number of the studies requested are already in progress in Study Group 8, but these will need to be finalized and Recommendations drafted as a priority matter. XIX
4. Preparation of the Technical Bases for the World Administrative Radio Conference, 1992
4.1 The ITU Plenipotentiary Conference (Nice, 1989) resolved that a World Administrative Radio Conference shall take place in the first quarter of 1992 for dealing with frequency allocations in certain parts of the spectrum, taking into account the Resolutions and Recommendations of WARC HFBC-87, WARC MOB-87 and WARC ORB-88 relating to frequency allocation; in addition this Conference may consider defining certain new space services and consider allocations to these services in frequency bands above 20 GHz (WARC-92; see Resolution No. 1(PL-B/1) of the Plenipotentiary Conference)..
4.2 WARC-92 will require intensive CCIR studies, in particular on sharing matters. For this purpose JIWP WARC-92, joining Study Groups 1, 2, 3, 4, 5, 6, 8, 9, 10 and 11, was established to prepare the CCIR report for the Conference. Apart from certain studies carried out in the JIWP, it will mainly coordinate the work and edit the report on the basis of studies carried out individually in other IWPs and JIWPs established to study specific issues relevant to WARC-92.
4.3 In Study Group 8, WARC-92 preparation has been organized as follows: — In addition to its regular work programme, IWP 8/13 (Decision 69 as amended at the Final Meeting) will study as a priority matter all questions within the scope of WARC-92 concerning future public land mobile telecommunication systems in the frequency range up to 3 GHz, including spectrum requirements and sharing questions with other services, and, through liaison with IWP 8/14, matters concerning systems of allied mobile and mobile satellite technologies. — In addition to its regular work programme, IWP 8/14 (Decision 81 as amended at the Final Meeting) will study as a priority matter all questions within the scope of WARC-92 concerning all mobile satellite services, including spectrum requirements and frequency sharing with other services. — IWP 8/15 (Decision 103) was established at the Final Meeting of Study Group 8 specifically for the preparation of WARC-92 and as an interface to JIWP WARC-92. It will collect all relevant input from IWPs 8/13 and 8/14 and undertake those additional studies within the scopes of Study Group 8 and of WARC-92 that are not yet covered by the above IWPs, for submission to JIWP WARC-92. — Finally, Study Group 8 will join JIWP 10-3-6-8/1 (Decision 97) established to develop more accurate sharing criteria between the broadcasting, fixed, mobile and amateur services in the band 2 to 30 MHz. This JIWP will report directly to JIWP WARC-92.
5. Main results of work during the study period 1986-1990 and future studies
Work at the Interim and Final Meetings was carried out in five working groups having topic areas as indicated in the sections below. Working Groups 8-A, 8-D and 8-E also reviewed the results of the work of IWPs 8/13 and 8/14 and of JIWP 8-10/1, respectively. This working group structure has proven very efficient over at least the. past two study periods. There has also been continuity in the chairmanships of working groups during the study period.
5.1 Working Group 8-A: Land mobile service, amateur and amateur satellite services
The Chairman was Dr. O. Villanyi (Hungary), who is also Vice-Chairman of Study Group 8. Study Group 8 activity in the land mobile service is very high and is tending to increase. Significant work includes:
5.1.1 Based on extensive and in-depth studies carried out by IWP 8/13, the new Recommendation 687 on objectives, services to be provided, frequency band considerations, and technical and operational characteristics for future public land mobile telecommunication systems (FPLMTS) intended for regional and world-wide use, was approved. The associated Report 1153 has also been extensively revised. The relevant parts in both these texts concerning frequency requirements for FPLMTS can be used as a basis for CCIR advice to WARC-92. The new Report 1155 was developed concerning the adaptation of mobile radiocommunication technology to the needs of developing countries. The new Report 1156 on digital cellular public land mobile telecommunication systems was developed. XX
5.1.2 Basic amendments were made to Report 903 on digital transmission systems.
5.1.3 Significant additions were made to Report 1022 on multitransmitter radio systems using quasi- synchronous (simulcast) transmissions in the land mobile service.
5.1.4 Several additions were made to Report 319 on characteristics of equipment and principles governing the assignment of frequency channels between 25 and 1000 MHz for the land mobile service.
5.1.5 Amendments were approved to Report 904 on automatic location determination in the land mobile service in order to include guidance systems.
5.1.6 Report 1025 was amended to take account of the latest developments concerning multi-channel access techniques for cordless telephones.
5.1.7 A major revision of Questions and Reports concerning the amateur and amateur-satellite services was undertaken.
5.2 Working Group 8-B: Maritime mobile service (telegraphy and telephony)
The Chairman was Mr. R. C. McIntyre (United States of America), who is also a Vice-Chairman o f Study Group 8. Significant work includes:
5.2.1 Recommendations 492 and 540 on narrow-band direct-printing were revised to take account of the comments of IMO concerning the NAVTEX system, accommodate single-frequency channel usage, standardize on additional facility codes and provide clarification of applicability of CCITT Recommenda tion U.63.
5.2.2 Report 1027 on the use of adaptive coding techniques under varying conditions of channel quality was further developed.
5.2.3 The new Recommendations 688 and 692 on promulgation of NAVTEX-type maritime safety information and use of single-frequency channels were adopted.
5.2.4 Amendments were made to Recommendations 493 and 541 on digital selective calling to include procedures for testing the system, provide position information, accommodate automatic station identifica tion and provide for automatic VHF radiotelephony operation. Recent sea trials resulted in several minor amendments to the Recommendations to remove ambiguities in the telecommand fields and acknowledge ment procedures.
5.2.5 Studies were further developed concerning maritime automated radiotelephone systems for connec tion to the public switched telephone network. A new Recommmendation 689 concerning VHF automated facilities and revised Report 1033 on MF/HF automated facilities were approved.
5.2.6 Studies on data communication systems were initiated and a new Report 1158 approved.
5.2.7 The new Question 97/8 was approved for transmitter identification for the maritime mobile service, improved use of VHF/UHF frequencies and automation of MF/HF maritime mobile communications.
5.3 Working Group 8-C: Radiodetermination, GMDSS and related matters
The Chairman was Mr. R Kent (United Kingdom). Significant work includes:
5.3.1 The work on radiodetermination during the study period has been heavy, with about 80% of input documents to the working group addressing the subject. During the study period the type of work undertaken has altered substantially in emphasis, changing from matters related to WARC MOB-87 to studies of the format, processing and frequency requirements of data transmissions for several different navigational purposes. These include differential corrections, electronic charts, shipborne transponders and remote monitoring of the status of marine navigational aids.
5.3.2 In addition, several Reports concerning navigational, systems were modified to reflect recent studies, and Recommendation 691, intended to ensure compatibility between radiolocation systems operating in the MF band using spread-spectrum techniques and other users of the band has been adopted. XXI
5.3.3 Report 774 on the technical parameters of radar beacons was substantially revised and the text of a possible Recommendation incorporated for further development. Two alternative methods of commanding user-selectable radar beacon facilities have been described, together with their respective advantages and disadvantages.
5.3.4 With respect to the GMDSS and related subjects, new Report 1167 and new Recommendation 690 concerning the power distribution of EPIRBs operating on the frequencies 121.5 MHz and 243 MHz were approved. EPIRBs which conform to this Recommendation will more easily be detected and located by the COSPAS-SARSAT system. The new Recommendation 693 on the technical characteristics of VHF DSC EPIRBs was also approved.
5.3.5 Report 1036, addressing frequencies for homing in the GMDSS, was updated in respect of the use of the frequency 406 MHz for homing purposes and the extension of the frequency band for search and rescue radar transponders (SARTs). As a consequence, Recommendation 628 was modified to extend the frequency range of a SART to 9200-9500 MHz and to provide for a more accurate range determination by the radar of a ship approaching a SART.
5.3.6 A number of Questions were modified, mainly as a result of WARC MOB-87. Question 45/8 was substantially amended and now addresses the need for distress and safety services in sparsely populated, uninhabited or remote areas of the world. In addition, Question 55/8 was amended to include studies on the remote monitoring of marine navigational aids. The new Questions 92/8 and 98/8 were prepared, one of which addresses the problem of a satisfactory world-wide interface between the radio and non-radio telecommunication services which will be used in the GMDSS, while the other concerns the transmission of digital data for the updating of electronic chart display systems.
5.4 Working Group 8-D: Maritime mobile-satellite service, land mobile-satellite service, mobile-satellite service and related matters, satellite EPIRBs, radiodetermination-satellite service
The Chairman was Dr. Y. Hirata (Japan), who is also a Vice-Chairman of Study Group 8. Significant progress was made concerning technical and operational matters in the mobile-satellite and radiodetermination- satellite services. Many of the new and revised texts were developed prior to the Interim Meeting in IWP 8/7 and later in IWP 8/14. The major results are described below.
5.4.1 . Questions concerning mobile-satellite matters
At the Interim Meeting a complete review and redrafting was made of the existing Questions and Study Programmes on mobile-satellite matters with the aim of improving the clarity and specificity of the study items and thus streamlining the studies. Subsequently, these new draft Questions were approved by correspondence (now Questions 82/8 to 91/8). Further improvements were made at the Final Meeting.
5.4.2 Texts on interference, frequency sharing and coordination matters in the mobile-satellite services
Several new and revised texts were developed concerning interference, sharing and coordination criteria. Work in this area will continue in IWP 8/14 as well as in JIWP “Coordination Area”.
New Report 1179 was developed concerning the methodology for the derivation of mobile-satellite service interference criteria. In the light of the rapid evolution of the mobile-satellite services, guidelines for two possible future Recommendations on frequency sharing and coordination are given as an Anhex to the Report. In addition, technical considerations for frequency sharing and system coordination for mobile-satellite systems are addressed in new Reports 1172 and 1185. New Report 1182 examines sharing between systems in the mobile-satellite and radioastronomy services in the band around 1660 MHz.
Report 766 on sharing with the GPS radionavigation-satellite system was revised to address the question of compatibility of terrestrial aeronautical public correspondence systems in the adjacent band with the GPS system. Report 917 on permissible interference in maritime mobile-satellite service channels was also updated. XXII
5.4.3 Systems in the land mobile-satellite service
Technical and operational considerations for systems in the land mobile-satellite service are addressed in new Report 1183 and in amendments to Report 770. Based on the work of IWP 8/14, a new Report 1177 dealing with the integration between terrestrial and satellite land mobile systems was also prepared.
5.4.4 Multi-purpose mobile-satellite systems
The new Report 1180 was prepared on design considerations for systems that provide land, maritime and aeronautical mobile-satellite services using shared system resources. In the light of the great interest in these systems, guidelines for a possible future Recommendation on this topic were included in an Annex to the Report.
5.4.5 Systems in the maritime-mobile satellite service
Signal propagation considerations in the maritime mobile-satellite service were updated in revisions to Reports 763 and 1048, and Report 921 was updated to include new material on ship earth stations using digital techniques.
5.4.6 Mobile-satellite systems for distress and safety
Substantial work was carried out on distress and safety systems in the mobile-satellite service. New Reports 1175 and 1184 describe distress alerting experiments conducted at 406 MHz and at 1.6 GHz using geostationary satellites. Recommendations 633 and 632 concerning transmission characteristics of satellite EPIRBs on 406 MHz and 1.6 GHz, respectively, were updated in order to take account of the latest developments. Reports 761 and 919 were also updated.
5.4.7 Others matters
Report 1050 on systems in the radiodetermination-satellite service was substantially revised to include new technical considerations. New Reports 1170 and 1176 on mobile-satellite systems were adopted on the use of satellites in highly inclined orbits and on interworking with terrestrial networks for data transmissions, respectively. Recommendation 546 was updated in order to provide for the applicability of the hypothetical reference circuit to all mobile-satellite systems.
5.5 Working Group 8-E: Aeronautical mobile service, aeronautical mobile-satellite service, aeronautical radiode termination
The Chairman was. Mr. J. Karjalainen (Finland), who is also a Vice-Chairman of Study Group 8. Significant work carried out included:
5.5.1 Matters relating to the compatibility between VHF sound broadcasting and the aeronautical services
Report 929 was substantially revised on the basis of the proposals by JIWP 8-10/1. New material was added for interference prediction methods developed in different countries or groups of countries. Flight tests carried out for the purpose of verifying the basic validity of the prediction models were reported. Report 929 as modified concludes, that further studies are still required in order to achieve realistic and reliable interference prediction methods. - Study Group 8 endorsed the decision by Study Group 10 that the work of the JIWP 8-10/1 should continue and should especially focus on methods of predicting interference and thus avoiding it occurring. Study Group 8 further decided to set concrete target dates for the work in the JIWP and to instruct it to produce a consolidated Report for publication in a separate booklet once approved by the Study Groups concerned at their next Interim Meetings. The JIWP was further instructed to produce a draft Recommen dation for consideration by Study Groups 8 and 10 at their next Final Meetings. Decision 71 was amended accordingly.
5.5.2 Matters relating to aeronautical public correspondence and to the aeronautical mobile-satellite service
Report 1051 dealing with a public mobile telephone service with aircraft was expanded and updated, mainly on the basis of proposals from IWP 8/14. Draft new Report 1173 which provides technical and operational considerations for aeronautical mobile-satellite communications was created at the Interim Meeting and substantially updated at the Final Meeting as the result of detailed consideration in IWP 8/14. XXIII
5.5.3 Matters related to radiodetermination for aircraft
In response to Question 94/8 the new Report 1186 dealing with spectrum requirements for radio altimeters operating in the band 4200-4400 MHz was approved. In response to Question 95/8 the new Report 1181 dealing with spectrum requirements for the Microwave Landing System in the band 5000-5250 MHz was approved. Both of these Questions relate to studies which WARC MOB-87 invited the CCIR to carry out. New Report 1174 was developed on potential interference caused by power-line carrier systems to Loran-C reception on board aircraft.
5.5.4 Matters relating to interference from MAC/PACKET-decoders
In order to assist Study Group 1 in their studies concerning potential interference from MAC and MAC/PACKET television systems, comments had been prepared at the Interim Meeting of Study Group 8 and submitted to Study Group 1. At the Final Meeting, this matter was considered further, in close cooperation with Study Group 1, on the basis of new input material and comments from Study Groups 10 and 11. The new Report 1101 (main responsibility with‘Study Group 1 and first established at the Interim Meeting) was updated at the Final Meeting.
6. Limitation of radiatibn from industrial, scientific and medical (ISM) equipment
In accordance with Resolution No. 63 of WARC-79, the CCIR in collaboration with CISPR, should specify as soon as possible, in the form of Recommendations, the limits to be imposed on radiation from ISM equipment inside and outside the bands designated for their use in the Radio Regulations. IWP 1/4, established to study the matter, has prepared the draft of Report 1104, which was considered and commented by Study Group 8 at its Interim Meeting. Study Group 8 participants to the Final Meeting attended meetings of the relevant Study Group 1 Working Group, which met at the same time, in order to make sure that due account was taken of the protection requirements of the mobile and radiodetermination services in the development of the final draft of Report 1104.
7. Special Rapporteurs of Study Group 8
Study Group 8 appointed the following Special Rapporteurs:
7.1 To CCITT Study Group III for GMDSS matters: Mr. U. Hammerschmidt, Federal Republic of Germany. 7.2 To the International Electrotechnical Commission (IEC): Mr. P. Brunschwig, France (re-appointed). 7.3 To IWP 1/4 of Study Group 1 concerning ISM matters: Mr. M. Lemaitre, France. 7.4 To the CCIR Coordination Committee for Vocabulary: Mr. F. Rose, United States of America (re appointed).
8. Status of texts
Apart from a thorough investigation into which Study Group 8 texts were outdated and could therefore be deleted, the Study Group, at its Final Meeting, considered a proposal for the new category of text “not for reprinting” (NRP). According to this proposal, older and unmodified, but still relevant texts should not be reprinted in a new edition of the CCIR Volumes in order to save printing costs, but have a reference to enable these texts to be retrieved from older editions. After considerable discussion on the advantages and drawbacks of this approach, it was finally agreed that only Reports should be considered for this new text category, noting that the validity and status of such not-reprinted text was in no way downgraded. Provisionally, Reports falling into this category have been identified. It was, however, recognized, that a final decision concerning this issue was a matter for the forthcoming CCIR Plenary Assembly. Rec. 494 1
SECTION 8A: LAND MOBILE SERVICE AND RELATED SUBJECTS
RECOMMENDATION 494 *
TECHNICAL CHARACTERISTICS OF SINGLE-SIDEBAND EQUIPMENT IN THE MF AND HF LAND MOBILE RADIOTELEPHONE SERVICE ,(1974)
The CCIR,
CONSIDERING
(a) that the growing use of single-sideband equipment in the land mobile service makes standardization increasingly important if mutual interference with other services is to be minimized; (b) that some administrations have developed technical standards for single-sideband equipment operating in the MF and HF land mobile radiotelephone service; (c) that the preferred technical characteristics for land mobile services should, as far as practicable, be compatible with those established for the aeronautical mobile (R) service and the maritime mobile services,
UNANIMOUSLY RECOMMENDS
1. that the preferred technical characteristics for MF and HF single-sideband land mobile equipment should be as follows:
1.1 General
1.1.1 class of emission J3E should be used; other classes of emission, e.g. H3E and R3E may be permitted, when necessary; 1.1.2 base and mobile stations should use the upper sideband; 1.1.3 the assigned frequency should be 1400 Hz higher than the carrier (reference) frequency; 1.1.4 for private mobile systems, the audio-frequency band should be 350-2700 Hz. For systems that can be connected to the public telephone network, the audio-frequency band may be increased to 300-3400 Hz.
1.2 Transmitters
1.2.1 the frequency tolerance should be ±100 Hz. For short periods, of the order of 15 min, the maximum deviation of ± 40 Hz should not be exceeded. The unwanted frequency modulation of the carrier should be sufficiently low to prevent harmful distortion; 1.2.2 the permitted amplitude variation without pre-emphasis should not exceed 6 dB over the audio frequency band specified in § 1.1.4, in either case;
This Recommendation terminates the study of Question 8/8, which has been deleted. f t / i - 2 Rec. 494
1.2.3 the power levels of unwanted emissions supplied to the antenna transmission line on any discrete frequency should, when the transmitter is driven at the rated output power* be in accordance with the following table:
TABLE I
Separation, A, Minimum attenuation below the level of either in kHz between, the frequency of the unwanted emission fundamental sideband component when modulated and the assigned frequency by two tones (kHz) (dB)
1-6 < A < 4-8 25 4-8 < A < 8 0 32 8 0 < A 37 (without exceeding the power of 50 mW)
Transmitters, using suppressed carrier emission may, as far as spurious emissions are concerned, be tested for compliance with this table by means of an input signal consisting of two audio tones that produce fundamental components of equal amplitude sufficient to produce - the rated output of the transmitter, with a frequency separation between the tones such that all intermodulation products occur at frequencies at least 1.6 kHz removed from the assigned frequency; 1.2.4 for J3E emission, the power of the carrier should be at least 40 dB below the rated output power. In the case of hand portable equipment the power of the carrier need not be less than 1 mW; 1.2.5 the in-band intermodulation products should be in accordance with Recommendation 326. The test frequencies should be:
f - 1900 H z ,/2 = 2600 Hz
1.3 Technical characteristics o f receivers
1.3.-1 the sensitivity should be such that for a 12 dB signal plus noise plus distortion to noise plus distortion (SINAD) ratio, the input signal should not be more than —131 dBW**; 1.3.2 the two-signal selectivity should be such that the ratio of the level of the unwanted signal to the level of the wanted signal should be at least +60 dB when the level of the wanted signal is set at the sensitivity level given in § 1.3.1 and the level of the unwanted signal is adjusted until the 12 dB SINAD ratio is degraded by 6 dB **. The standard signal spacing for measuring receiver adjacent-signal selectivity should be 5 kHz; 1.3.3 the permitted amplitude variations without post-detector de-emphasis should not exceed 6 dB over the audio-frequency band specified in § 1.1.4, in either case; 1.3.4 the frequency stability should be within ± 100 Hz (with a maximum deviation of ± 60 Hz for short periods of the order of 15 minutes); ' 1.3.5 unwanted emissions on any discrete frequency should not exceed 2 nanowatts, measured either as a power level at the antenna terminals or as an effective radiated power from the equipment itself; 1.3.6 the spurious response rejection ratio should not be less than 60 dB in relation to the sensitivity of the receiver measured in accordance with § 1.3.1. In certain cases, the image frequency attenuation can be reduced to 50 dB for technical and economic reasons;
2. that a special requirement, necessary for single-sideband equipment used in the MF and HF land mobile service, is that, when an internal audio-frequency generator is used to modulate a transmitter to facilitate receiver tuning, the audio frequency should be 1000 Hz ± 1 Hz.
* The rated output power may differ from that which would be established by Recommendation 326 and may be limited, on the other hand, by reasons of thermal dissipation, supply current limitations, or factors other than intermodulation products. ' ** The methods of measuring these characteristics should follow, as far as practicable, the practices as defined by the IEC. Rec. 478-4 3
RECOMMENDATION 478-4
TECHNICAL CHARACTERISTICS OF EQUIPMENT AND PRINCIPLES GOVERNING THE ALLOCATION OF FREQUENCY CHANNELS BETWEEN 25 AND 1000 MHz FOR THE LAND MOBILE SERVICE
(Question 7/8) (1970-1974-1978-1982-1990) The CCIR,
CONSIDERING
(a) that certain technical characteristics of equipment and stations in the land mobile service are of importance in connection with radio interference between the stations of different countries; (b) that agreement is desirable on certain technical characteristics of land mobile equipment, to minimize mutual interference and to facilitate the use of the same types of equipment in different countries in a geographical region; '(c) that agreement is desirable on the practices governing the choice of station antenna height and effective radiated power taking into account geographical features, required communications range and system parameters; (d) that agreement is desirable on the practices governing the allocation of channels in the land mobile service, in order to minimize mutual interference and to obtain economy of use of the frequency spectrum; (e) that in some areas, different values for the technical characteristics of equipment are required, in order to minimize mutual interference; (f) that the values agreed upon should be based on circumstances that typify high density radio usage areas and should be a compromise between optimum spectrum utilization and cost; (g) that under some circumstances, e.g. where channel assignments and/or types of system operation permit, not all recommended technical characteristics are required to minimize mutual interference; (h) that in the land mobile service, ultimate spectrum utilization is determined by assignment techniques, suppression and rejection of unwanted radiation,. and other means additional to the actual characteristics of the equipment; (j) that the characteristics of non-vehicular mounted portable equipment require further study; (k) that in Opinion 42, the IEC has been invited to advise the CGIR of any methods of measurement applicable to radio equipment used in land mobile services,
UNANIMOUSLY RECOMMENDS
1. that the preferred technical characteristics for VHF and UHF land mobile equipment should be as follows:
1.1 Transmitter characteristics
1.1.1 Necessary bandwidth and class o f emission
1.1.1.1 For class A3E: 6 kHz 1.1.1.2 For class F3E: 30 and 25 kHz channel separations: 16 kHz 20 kHz channel separation: in frequency bands up to 160 MHz: < 16 kHz, dependent on deviation in frequency bands above 160 MHz: 14 kHz 12.5 kHz channel separation: 8.5 kHz 4 Rec. 478-4
1.1.2 Frequency tolerance Within the temperature ranges specified by each administration according to the environment, and for specified ranges ,of primary supply voltages, the frequency error of any carrier emission should not exceed the values given in Table I.
TABLE I - Tolerances for each frequency band
Frequency band
35 MHz 80 MHz 160 M Hz 300 MHz 450 MHz 900 MHz
Channel spacing kH z(i) 10-6 kH z(i) lO -6 kH z(i) 10-6 kH z(i) lO -6 kH z(l) 10-6 kH z(i) lO -6 (kHz)
20, 25 and 30 0.7 20 I-6 20 1.6 10 2.1 7 2.25 5 2.7 3
12.5 - - 1.0 12 1.3 8 - - 1.35 3 1.35 1:5
(i) Approximate values.
1.1.3 Adjacent channel power
1.1.3.1 25 and 30 kHz channel spacing: 25-500 MHz: at least 70 dB below carrier power in a bandwidth of 16 kHz 500-1000 MHz: at least 65 dB below carrier power in a bandwidth of 16 kHz 1.1.3.2 20 kHz channel spacing: At least 70 dB below carrier power in a bandwidth of 14 kHz, A/: 4 kHz (A/: the maximum permissible frequency deviation) At least 60 dB below carrier power in a bandwidth of 14 kHz, A/: 5 kHz (A/: the maximum permissible frequency deviation) 1.1.3.3 12.5 kHz channel spacing: At least 60 dB below carrier power in a bandwidth of 8.5 kHz. In each case, it is not necessary to reduce the adjacent channel power below 0.25 pW. -
1.1.4 Conducted spurious emissions Spurious emissions on discrete frequencies, when measured in a non-reactive load equal to the nominal output impedance of the transmitter, should not exceed 2.5 pW for transmitter carrier powers up to 25 W. For carrier powers in excess of 25 W, the level of any spurious emission should be at least 70 dB below the carrier power. In some radio environments lower values may be required.
1.1.5 Cabinet radiation The cabinet radiated power should not exceed 25 pW. In some radio environments, a lower value may be required.
1.2 Receiver characteristics
1.2.1 Reference sensitivity The reference sensitivity should be less than 2.0 pV, e.m.f., for a given reference signal-to-noise ratio at the output of the receiver.
1.2.2 Adjacent channel selectivity
1.2.2.1 20, 25 and 30 kHz channel spacing: The adjacent channel selectivity should not be less than 70 dB. 1.2.2.2 12.5 kHz channel spacing: The adjacent channel selectivity should not be less than 60 dB. Rec. 478-4 5
1.2.3 Radio-frequency intermodulation
The intermodulation response rejection ratio should not be less than 70 dB.
1.2.4 Spurious responses
At any frequency separated from the nominal frequency of the receiver by more than one channel spacing, the spurious response rejection ratio should not be less than 70 dB.
1.2.5 Conducted spurious emissions
The power of any spurious emission measured at the antenna terminals with matched termination, on any discrete frequency, should not exceed 2.0 nW. In some radio environments, lower values may be required.
1.2.6 Cabinet radiation
The effective radiated power of any spurious emission on any discrete frequency up to 70 MHz should not exceed 10.0 nW. Above 70 MHz, the spurious emissions should not exceed 10 nW by more than 6 dB/octave relative to the value at 70 MHz in frequency up to 1000 MHz. In some radio environments, lower values may be required. I
1.3 Station characteristics
1.3.1 Frequency characteristics
1.3.1.1 Radio-frequency band of operation: , According to the Table of Frequency Allocations contained in Article 8 of the Radio Regulations; in particular the bands of 35, 80, 160, 300, 450 and 900 MHz. 1.3.1.2 Separation of the transmit and receive frequencies for full duplex operation: 35 MHz band: 4 MHz 80-MHz band: 3 MHz 160 MHz band: 3 MHz 300 MHz band: 4 MHz 450 MHz band: 5 MHz The above are practical minimum values determined by cost and isolation required; smaller separations are possible using higher quality and more costly duplexers. 900 MHz band: 45 MHz This preferred value is determined by the desirability to provide for high capacity systems with a great number of channels. However, in some systems, greater transmit/receive frequency separation might be required. In practice, the actual separations used may be,other than the values given and may be determined by other factors than were used in this Recommendation. Frequencies should preferably be assigned with a constant separation between the transmit and receive frequencies over the whole of a band or the sub-bands within a band.
\ 1.3.2 Effective radiated power and antenna height
It is recognized that the responsibility for limiting the effective radiated power and antenna height over the average level of the ground rests with administrations, taking into account: — the general requirement not to radiate more power than is necessary and not to use larger antenna heights than necessary; — the required range and communication quality; — the frequency band of operation; 6 Rec. 478-4
— the terrain over which service is required; . ^ — special conditions, e.g. diversity reception at remote receiving stations; — the potential intra-service or inter-service effects between the mobile service and other radio services.
1.3.3 Antenna system
Vertically polarized.
2. that reference should be made to Part A of Report 319 for information on some of the existing practices adopted by administrations in the allocation of channels in the land mobile service between 25 and 1000 MHz;
3. that international agreement should be reached on as many aspects as possible of the practices for the allocation of channels in the land mobile service between 25 and 1000 MHz, and that reference should be made to Part A of Report 319;
4. that reference should also be made to the relevant IEC publications on methods of measurement. Rec. 539,2 7
RECOMMENDATION 539-2*
TECHNICAL AND OPERATIONAL CHARACTERISTICS OF FUTURE INTERNATIONAL RADIO-PAGING SYSTEMS**
(Question 12/8) (1978-1982-1986) The CCIR,
CONSIDERING
(a) that agreed technical and operational characteristics for systems and equipment could facilitate the introduction of international paging; (b) that certain technical characteristics of equipment and stations used in paging systems are of importance in connection with the grade of service offered and in respect of the radio interference between the stations of different countries; (c) that the use of agreed frequency bands and technical characteristics could reduce the risk of mutual interference between radio-paging systems and interference with other radio systems; (d) that the public radio-paging systems making use of the national and international public switched telephone networks should be designed as extensions of those networks; (e) that additional messages of different types are operationally required by subscribers to such paging services thus increasing the number of paging codes required or complicating the structure of a single message code;
( f ) that the ultimate paging address capacity of a system is generally decided early in the planning process; (g) that the most economical way of providing international radio-paging services may be as an extension of national systems; (h) that the requirements for international radio paging can usually be anticipated in the planning of national systems,
UNANIMOUSLY RECOMMENDS
that the following technical and operational characteristics of the systems, stations and equipment for land mobile radio paging should be adopted for systems intended for future international use:
1. Operational and system characteristics
1.1 Design principles
The radio-paging system should be designed as an extension of the telephone network.
1.2 Receiver operation when changing paging zones '
The procedure by which a user can obtain service when moving from one paging zone or system to another (even internationally), should be as simple as possible. Manual adjustment of the receiver should not be required.
* The Director of the CCIR is requested to bring this Recommendation to the attention of the CCITT, particularly in reference to § 2.2 and 3.2. ** Radio paging: a non-speech, one-way, personal selective calling system with alert, without message or with defined message such as numeric or alpha-numeric. (This definition should be brought to the attention of the CM V.) 8 Rec. 539-2
1.3 Additional messages The system should enable the transmission and reception of additional messages of different types, such as the telephone number of the caller or longer numeric or alpha-numeric messages. It should be possible to use different types of receivers for different types of messages. Further study is however needed to determine the types and lengths of such messages.
1.4 Priority calls It should be possible to have groups of users that are given priority during times of high traffic load.
1.5 Legitimation codes It should be possible for subscribers who wish so, to have legitimation codes that have to be used by the caller when calling such a subscriber.
1.6 Group calls It should be possible to call several subscribers as a group.
1.7 Receiver identification Each receiver should be identified uniquely in the system in which it is to operate. Where administrations combine national systems to give international service, they should ensure that no two receivers used for this purpose should have the same identity, except when required for group calling.
1.8 Battery saving techniques As low power consumption is essential for the receiver, the system should include methods for battery saving.
2. Control centre characteristics
2.1 Function The control centre should perform the-store and forward functions for paging calls for national and international service.
2.2 Telephone network signals The control centre forms part of the switched telephone network. It therefore has to accept and generate telephone network signals agreed for national and international networks. The format of such signals is a matter on which the appropriate CCITT Study Group should advise.
2.3 Messages and signals to caller The control centre should generate call acceptance and call rejection messages or signals to the caller. These messages and signals should be immediately recognizable by the caller even when placing international calls. The messages and signals should not confuse persons who reach the paging system by error,
3. Telephone network requirements
3.1 Dialling codes , The dialling codes used to gain access to the paging system should conform to those agreed for national and international use. ,
3.2 Dialling format The format should be such that the dialling codes used in international paging services may be transmitted over the international telephone network. Although it may be possible to find suitable transmitter codes with sufficient capacity for international paging, there are some problems in finding sufficient telephone dialling codes. Further study on this aspect is therefore needed.
3.3 Group call codes
The ability to page groups of subscribers according to § 1.6 should be included in the dialling codes. Rec. 539-2 9
4. Transmitters and distribution of paging signals
4.1 Frequency o f operation
For international service, at least one common international frequency channel or band should be assigned. Further study is needed to enable the recommendation of suitable frequencies.
4.2 Multiple transmitter zones
In multiple transmitter zones, a single radio frequency channel, if possible, is preferred so as to avoid multi-channel receivers. The transmitters can operate either sequentially or simultaneously.
4.3 Rate and type of data modulation
For international service these parameters must be agreed between the corresponding administrations. For Radio Paging Code No. 1, the preferred parameters are currently: — data transmission rate: 512 bit/s (with an accuracy of ± 1 x 10-5); — modulation type: direct FSK in non-return-to-zero manner, with positive frequency shift representing binary 0 and negative frequency shift for binary 1 and frequency deviation appropriate for the assigned channel, e.g. ± 4.5 kHz for a 25 kHz channel. 512 bit/s was selected as a compromise between the needs of various multitransmitter situations. Further study is needed to enable the recommendation of parameters for universal use.
4.4 Phase equalization
In systems where some or all transmitters operate simultaneously, the modulating signals should be equalized so as to be compatible with the data transmission rate and the modulation type. For the preferred values in § 4.3, the modulation time delay between adjacent transmitters should not exceed 488 ps.
4.5 Frequency off-set
The radio frequency off-set for transmitters operating simultaneously on a common radio frequency channel should be maintained within limits compatible with the data transmission rate and the modulation type. Further studies are needed to enable values to be recommended.
4.6 Transmitter frequency tolerance
The transmitter frequency tolerance should be, at least, in accordance with Recommendation 478. For the preferred values in § 4.3, the tolerance should be less than 5 x 10~6. Where simultaneous transmitter operation with frequency off-set is used, tighter tolerances may be needed.
4.7 Other transmitter characteristics ,
For the other transmitter characteristics, the values should be in accordance with Recommendation 478.
5. Receivers
5.1 Size, weight and cost should be as small as possible.
5.2 Power consumption
Power consumption should be kept as low as possible. Battery saving methods as offered by the system should be implemented in the receiver.
5.3 Sensitivity
The calling sensitivity should be less than 10 pV/m, for reference calling probability (see IEC Publica tion 489 — Part 6).
5.4 Selectivity
The adjacent channel selectivity should not be less than 60 dB in the VHF band. A lower figure may be appropriate for the UHF band. 10 Rec. 539-2
5.5 Spurious emission
The value of 10 nW should not be exceeded at any frequency up to 70 MHz. Above 70 MHz, the spurious emission should not exceed 10 nW by more than 6 dB/octave in frequency up to 1000 MHz. However, lower values are preferable (e.g. 2 nW or less) in view of the possible large number of receivers in certain areas.
6. Signalling code and format
Refer to Recommendation 584. Further study is needed. In this study, the following factors, among others, should be studied and taken into account: — address and message capacity requirements; — expected calling rate; — error detecting requirements; — error correcting requirements; — implementation possibilities. Rec. 584-1 11
RECOMMENDATION 584-1 *
STANDARD CODES AND FORMATS FOR INTERNATIONAL RADIO PAGING**
(Question 12/8, Study Programme 12A/8)
(1982-1986)
The CCIR,
CONSIDERING
(a) Recommendation 539, Reports 499 and 900 which describes codes and formats presently used by a number of administrations;
(b ) that the studies necessary to define the requirements for international radio-paging systems are not complete;
■(c) that the results of such studies may make it desirable to amend any standard selection on the basis of the present limited information;
(d ) that some administrations have an urgent need to implement national radio-paging systems which might be developed to provide for international radio paging;
(e) that, among other things, standard code(s) and format(s) are necessary to permit international radio paging;
( f ) that, for paging systems unlikely to be extended to provide for international paging, some other codes might be more suitable,
RECOMMENDS***
1. that the codes and formats described in Annex I are generally suitable for national use and should be considered for systems which an administration might intend to extend to international paging;
2. that system design should allow for possible future changes in the recommended codes and formats;
3. that studies should continue in order to define the requirements for international paging systems.
* The Director of the CCIR is requested to bring this Recommendation to the attention of the CCITT in relation to Recommendation 539. ** Radio paging: non-speech, one-way, personal selective calling system with alert, without message or with defined message such as numeric or alphanumeric. (This definition should be brought to the attention of the CMV.) *** The Administrations of Brazil and Japan reserve their position with respect to this Recommendation. * 12 Rec. 584-1
ANNEX I.
RADIO-PAGING CODE No. 1
1. Code and format
A transmission consists of a preamble followed by batches of complete codewords, each batch commencing with a synchronization codeword (SC). The format of the signals is illustrated in Fig. 1. Transmission may cease at the end of a batch when there are no further calls.
C 4 4 — ------A ^ k B f\ ______s o 1 c 1 1
101010
0 -► 4 —
$ c i i i i i 1 l 1
FIGURE 1 - Signal format
A: preamble. Duration at least 576 bits = the duration 1 batch + 1 codeword B: first batch C: second and subsequent batches D: one frame = 2 codewords SC: synchronization codeword Note. - 1 batch = synchronization codeword + 8 frames = 17 codewords.
1.1 Preamble
Each transmission starts with a preamble to aid the pagers to attain bit synchronization and thus help in acquiring word and batch synchronization. The preamble is a pattern of reversals, 101010... repeated for a period of at least 576 bits, i.e. the duration of a batch plus a codeword.
1.2 Batch structure
Codewords are structured in batches which comprise a synchronization codeword followed by 8 frames, each containing 2 codewords. The frames are numbered 0 to 7 and the pager population is divided into 8 groups. Thus each pager is allocated to one of the 8 frames according to the 3 least significant bits (lsb) of its 21 bit identity (see § 1.3.2), i.e. 000 = frame 0, 111 = frame 7, and only examines address codewords in that frame. Therefore each pager’s address codewords must be transmitted only in the allocated frame. Message codewords for any receiver may be transmitted in any frame but follow, directly, the associated address codeword. A message may consist of any number of codewords transmitted consecutively and may embrace one or more batches but the synchronization codeword must not be displaced by message codewords. Message termination is indicated by the next address codeword or idle codeword. There is at least one address or idle codeword between the end of one message and the address codeword belonging to the next message. In any batch, wherever there is no meaningful codeword to be transmitted, an idle codeword is transmitted. Rec. 584-1 13
1.3 Types of codewords
Codewords contain 32 bits which are transmitted with the most significant bit first. The structure of a codeword is illustrated in Fig. 2.
1 2-19 20-21 22-31 32
1 J K L Binary “0” Binary
K L | | “1” Binary
FIGURE 2 - Form of address and message codewords E : bit number I : function bits F : address codeword K : check bits G: message codeword L: even parity bit H : flag bit M: message bits (2-21) I : address bits (2-19)
1.3.1 Synchronization Codeword
The synchronization codeword is shown in Table I:
TABLE I
Bit N o. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Bit 0 1 1 1 1 1 0 0 1 1 0 1 0 0 1 0
Bit N o. 17 18 19 20 21 22 23 . 24 25 26 27 28 29 30 31 32
Bit 0 0 0 1 0 1 0 1 1 1 0 1 1 0 0 0
1.3.2 Address Codewords
The structure of an address codeword is illustrated in Fig. 2. Bit 1 (the flag bit) of an address codeword is always a zero. This distinguishes it from a message codeword. Bits 2-19 are address bits corresponding to the 18 most significant bits of a 21 bit identity assigned to the pager. For information regarding the least significant bits see § 1.2. Bits 20 and 21 are the two function bits which are used to select the required address from the four assigned to the pager. Hence the total number of addresses is 223 (over 8 million). Bits 22 to 31 are the parity check bits (see § 1.4) and the final bit (bit 32) is chosen to give even parity. 14 Rec. 584-1
1.3.3 Message Codewords
The structure of a message codeword is shown in Fig. 2. A message codeword always starts with a 1 (the flag bit) and the whole message always follows directly after the address codeword. The framing rules of the code format do not apply to a message and message codewords continue until terminated by the transmission of the next address codeword or idle codeword. Each message displaces at least one address codeword or idle codeword and the displaced address codewords are delayed and transmitted in the next available appropriate frame. Although message codewords may continue into the next batch, the normal batch structure is maintained, i:e., the batch will consist of 16 codewords, preceded by a synchronization codeword. At the conclusion of a message any waiting address codewords are transmitted, starting with the first appropriate to the first free frame or half frame. Message codewords have 20 message bits, viz bit 2 to bit 21 inclusive and these are followed by the parity check bits obtained according to the procedure outlined in § 1.4 below.
1.3.4 Idle Codeword
In the absence of an address codeword or message codeword, an idle codeword is transmitted. The idle codeword is a valid address codeword, which must not be allocated to pagers and has the following structure as shown in Table II:
TABLE II
Bit N o. 1 . 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Bit 0 1 1 1 1 0 1 0 1 0 0 0 1 0 0 1
Bit N o. 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
Bit 1 1 0 0 0 0 0 1 1 0 0 1 0 1 1 1
1.4 Codeword Generation (31: 21 BCH + Parity)
Each codeword has 21 information bits, which correspond to the coefficients of a polynomial having terms from x30 down to x10. This polynomial is divided, modulo-2, by the generating polynomial x10 + x9 + x8 + x6 + x5 + x3 + 1. The check bits correspond to the coefficients of the terms from x9 to x° in the remainder polynominal found at the completion of this division. The complete block, consisting of the information bits followed by the check bits, corresponds to the coefficients of a polynomial which is integrally divisible in modulo-2 fashion by the generating polynomial. To the 31 bits of the block is added one additional bit to provide an even bit parity check of the whole codeword.
2. Message formats
Although in principle, any message format can be inserted into message codewords, the following formats are regarded as standard. Adherence to these standards will enable a greater measure of interworking to be possible. The formats are not mixed within any one message.
2.1 “Numeric-only” message format
The “numeric-only” format is provided for the transmission of messages which may be represented solely in decimal numerals together with spaces, hyphens, opening and closing brackets, an urgency symbol “U” and one other symbol. There are 4 bits per character in this format and its use will save air-time compared to the other format. The address which introduces a message (or segment of a message) using this format has its function bits set to 00. The character-set used for the message is as shown in Table III which is based on Binary Coded Decimal (BCD). The bits of each character are transmitted in numerical order starting with bit No. 1. Characters are transmitted in the same order as they are to be read and are packed 5 per message codeword. Any unwanted part of the last codeword of the message is filled with space characters. Rec. 584-1 15
TABLE III - "Numeric-only’’ character set
4-bit Combination Displayed character
Bit No.: 4 3 2 1
0 0 0 0 0 0 0 0 1 1 0 0 1 0 2 0 0 1 1 3 0 1 0 0 4 0 1 0 1 5 0 1 1 0 6 0 1 1 1 7 1 0 0 0 8 1 0 0 1 9 1 0 1 0 Spare 1 0 1 1 U (urgency indicator) 1 1 0 0 Space 1 1 0 1 Hyphen ' 1110 z : 1111 c z
2.2 Alpha-numeric or general data format
This format can be used for the transmission of messages requiring a greater range of characters than that provided within the “numeric-only” format but it may also be used to replace the latter when circumstances make this essential or desirable. There are 7 bits per character in this format. The pager address which introduces a message (or segment of a message) using this format has its function bits set to 11. The CCITT Alphabet No. 5 (7 bits per character) is used in this format. As in the case of the “numeric-only” format, bit order starting with bit No. 1 of each character, and character reading order are preserved in transmission. The complete message is partitioned into contiguous 20 bit blocks for the purpose of filling consecutive message codewords. Thus a character may be split between one message codeword and the next. Any unwanted part of the last codeword of the message is filled with appropriate non-printing characters such as “End of Message”, “end of Text”, Null, etc. All characters; except Null, are complete. 16 Rec. 622
RECOMMENDATION 622
TECHNICAL AND OPERATIONAL CHARACTERISTICS OF ANALOGUE CELLULAR SYSTEMS FOR PUBLIC LAND MOBILE TELEPHONE USE
(Questions 37/8, 39/8) (1986) The CCIR,
CONSIDERING
(a) Report 740; (b) Report 742, which gives details of a number of present analogue cellular systems; (c) that on-going studies necessary to specify future international cellular mobile telephone systems are not yet complete; (d) that many administrations are planning, implementing, or operating national and international mobile telephone systems which use analogue speech modulation and which have high capacity and spectrum efficiency; (e) that a limitation of the number of different analogue cellular systems would greatly facilitate the international use of these systems and would reduce equipment cost,
UNANIMOUSLY RECOMMENDS
that the following technical and operational characteristics of cellular land mobile telephone systems should be adopted for systems intended for international or regional use:
1. General characteristics
1.1 Operational aspects
The following general operational aspects should apply: — automatic setting up and charging of calls to and from the mobile station; — the ability to set up calls between the mobile station and any fixed telephone subscriber or other mobile telephone subscriber within the system; — fees should be charged in a manner consistent with principles of the public switched telephone network (PSTN); — the blocking probability should be designed in a manner similar to the PSTN services; — continuous control of call quality should be maintained, with automatic hand-over between adjacent base stations within one system if needed; full duplex operation; — speech quality should be comparable to that offered in the existing analogue PSTN.
1.2 Cellular properties
The following general aspects should apply: — possibility to accommodate more than one base station in a service area; — “hand-over” from one site to another, i.e. from one radio frequency to another if necessary; — re-use of the same RF assignment simultaneously by more than one base station and for more than one communication; — growth: the system may be able to start with a few large cells and gradually grow until many small cells are created at points of highest traffic density.
1.3 Service protection
— A transmitted serial number or some similar technique should prohibit the use of stolen units or use by unauthorized callers; — unwanted intelligible signals (cross-talk) should be avoided or suppressed; — the introduction of means to ensure privacy of communication should not be excluded by the design. Rec. 622 17
1.4 Services offered
The following services should not be excluded: — non-voice services, such as data services, etc.; — equipment mounted in any vehicle; — hand-held equipment; — other enhancements consistent with the mobile service, such as abbreviated dialling, etc.
2. Technical characteristics
2.1 Radio cell configuration
The radio cell configuration should be determined by thermal and environmental noise performance, co-channel interference, the typical multipath (Rayleigh) fading of mobile channels, terrain variability, the antenna patterns selected, and the service quality desired.
2.2 Control channel configuration 2.2.1 Control channel usage: the following two methods are permissible: — the exchange of control signals over channels which can also be used as communication channels; — the provision of channels dedicated either to control or communication but not both. Both methods reduce the total traffic capacity of the system; the choice between the above methods depends primarily on the amount of signalling traffic. 2.2.2 Seizure: multiple seizure reduction techniques such as the busy/idle status on control channels should be used to reduce the effects of collisions during attempts on the same control channel.
2.3 Speech quality
For an analogue system, voice processing using a 2 : 1 syllabic compandor might be employed to improve speech quality.
2.4 Signalling reliability
To improve signalling reliability, the following methods are preferred: — forward error correcting coding such as BCH code; — repeated control signal transmission; — compelled techniques, e.g. recycle (ARQ) and repeat back techniques; — diversity techniques.
2.5 RF equipment characteristics
— Employment of diversity techniques should not be precluded; — Recommendation 478 * should apply to each frequency band employed.
3. Operational characteristics
3.1 Call processing
The following system functions should apply to the cellular system: — radio channel assignment and set-up control when calls occur; — radio channel release when calls terminate.
* Except that cellular systems, using exclusive frequency bands, because of their inherent separation in both frequency and space, might have relaxed adjacent-channel and spurious-emission requirements within their own bands. 18 Rec. 622
3.2 Supervision To supervise radio channel status and to maintain necessary quality, the system shall perform one or several of the following functions: — appropriate control channel selection and identification of the registration areas for the mobile station; — radio cell assignment of the mobile station for origination and/or termination of calls; — speech channel status monitoring, as appropriate; — monitoring the proper speech channel assignments; — speech channel quality monitoring and appropriate radio cell selection for hand-over if necessary; — monitoring the speech channel reassignment, whenever necessary; — proper control monitoring at termination.
3.3 Location registration In accordance with Recommendation 624.
3.4 PSTN interface In accordance with CCITT Recommendation Q.70.
3.5 Numbering plan In accordance with CCITT Recommendation E.213. Rec. 687 19
RECOMMENDATION 687
FUTURE PUBLIC LAND MOBILE TELECOMMUNICATION SYSTEMS (FPLMTS)
(Question 39/8) (1990) The CCIR,
CONSIDERING
(a) Recommendation No. 205 of the WARC MOB-87; (b) that the cost of radio and Very Large Scale Integration (VLSI) technology is continually decreasing, thus making competitive, in a number of cases, the alternative option of a radio approach for accessing voice and non-voice telecommunication services; (c) that different future systems are under study; (d) that system compatibility is necessary for international operation, and that commonality is desirable in any event to ensure that the overall systems cost per mobile user is significantly less than it is with present systems; (e) the need for a flexible system structure able to match network investment to the revenue growth, to adapt readily to environmental factors and to respond, to new developments without restricting innovation; (f) the possible need for common channels or frequency bands to allow regional and/or world-wide operation, particularly with the increasing use of personal (hand-held, portable) terminals; (g) that the use of internationally agreed frequency bands also facilitates the planning of national networks and reduces the risk of harmful interference with other radio services; (h) the increasing importance of the various types of non-voice telecommunication services; (j) the relevant CCITT Recommendations and on-going studies; (k) that mobile terminals of the FPLMTS may be used to access mobile satellite systems for use on land, ships and aircraft; (I) the allocation of radio spectrum in the 1.5-1.6 GHz band by the WARC MOB-87 to the land mobile-satel lite service; (m) that there is a need for mobile terminals to roam between public land mobile telecommunication networks , in different countries; (n) that a standardized radio interface would facilitate the roaming of mobile units between networks; (o) that users may want to be able to use the same terminals and procedures as in the fixed network ISDN to access similar telecommunication services in FPLMTS; (p) Questions 77/8 and 38/9,
UNANIMOUSLY RECOMMENDS
that future public land mobile telecommunication systems intended for regional and/or world-wide use should conform to the following objectives and characteristics:
1. Objectives
1.1 General objectives
FPLMTS aim to achieve the following primary general objectives: 1.1.1 to make available voice and non-voice telecommunication services to users who are on the move or whose location may change (mobile users); 1.1.2 to provide these services over a wide range of user densities and geographic coverage areas; 1.1.3 to make efficient and economical use of the radio spectrum consistent with providing service at an acceptable cost; 1.1.4 to provide, as far as practical, a service of high quality and integrity, comparable to the fixed network; 1.1.5 to accomodate a variety of mobile terminals ranging from those which are small enough to be easily carried on the person (personal pocket radio) to those which are mounted in a vehicle; 1.1.6 to provide a framework for the continuing extension of mobile network services, and access to services and facilities of the fixed network (PSTN/ISDN) subject to the constraints of radio transmission, spectrum matters and system economics; 1.1.7 to admit the connection of mobile users to other mobile users or fixed users, using the fixed network (PSTN/ISDN) or other telecommunication networks as appropriate; 1.1.8 to permit the use of the FPLMTS for the purpose of providing its services to fixed users under conditions approved by the appropriate national or regional authority, either permanently or temporarily, either in rural or urban areas; 1.1.9 to admit the provision of service by more than one network in any area of coverage; 1.1.10 to allow mobile and fixed network users to use the services irrespective of location (i.e. national and international roaming); 1.1.11 to provide an open architecture which will permit the easy introduction of technology advance ments, as well as different applications; 1.1.12 to allow the coexistence with, and interconnection with, mobile systems which use direct satellite links taking into consideration CCITT Recommendation E.171; 1.1.13 to provide a modular structure which will allow the system to start from as small and simple a configuration as possible and grow as needed, both in size and complexity within practical limits.
Technical objectives
FPLMTS aim to achieve the following primary technical objectives: 1.2.1 to support integrated communication and signalling; 1.2.2 to establish signalling interface standards in terms of the Open System Interconnection (OSI) model. FPLMTS aim to achieve the following secondary technical objectives: 1.2.3 to provide for additional levels of security (for voice and data services) compared to that contained in § 1.1.4. In addition, to allow for the provision of end-to-end encryption for voice and data services; 1.2.4 to provide service flexibility which permits the optional integration of services such as mobile telephone, dispatch, paging and data communication, or any combination thereof; 1.2.5 to support terminal interfaces which allow the alternative use of terminal equipment in the fixed ISDN network; 1.2.6 to support equipment and component design that can withstand typical rural conditions (rough roads, dusty environment, extreme temperatures and humidity, etc.); 1.2.7 to accomodate the use of repeaters for covering long distances between terminals and base stations, providing this does not constrain the specification of the radio interfaces; 1.2.8 to allow the connection of PABXs or small rural exchanges to mobile stations.
Operational objectives
FPLMTS aim to achieve the following primary operational objectives: 1.3.1 to provide for the required user authentication and billing functions; 1.3.2 to provide for unique user identification and PSTN/ISDN numbers in accordance with appropriate CGITT Recommendations; 1.3.3 to provide for a unique equipment identification scheme; 1.3.4 to enable each mobile user to request particular services, and initiate and receive calls, as desired. FPLMTS aim to achieve the following secondary operational objectives: 1.3.5 to provide an indication to the paying party of added call charges e.g. due to roaming; Rec. 687 21
1.3.6 to allow the system to be configured for special conditions where mobility between cells, or even within a cell is not required; or where a high traffic per user is required; 1.3.7 to take account of the communications requirements for road traffic management and control systems; 1.3.8 to allow for extension of the cell size in rural or remote areas, providing this does not constrain the specification of the radio interfaces.
2. Services
2.1 General 2.1.1 FPLMTS should offer the services available in the PSTN/ISDN and other public networks, as far as possible, bearing in mind the differences in the characteristics of the fixed network and mobile radio environment; 2.1.2 FPLMTS may also offer additional services, taking into account the special nature of mobile communications; 2.1.3 FPLMTS should be designed in such a way that the calling user does not have to know the location of the mobile; 2.1.4 it should be possible for stations in FPLMTS to be used in the maritime and aeronautical environment, to the extent permitted by national or international regulatory authorities; 2.1.5 it should be possible for FPLMTS to be used as a temporary or permanent substitute to fixed networks where fixed network facilities are limited or not available, or more generally where reasons of convenience or economics make this desirable. The system should then be capable of adaptation to these conditions (i.e. higher traffic per user, no mobility between cells or even within a cell); 2.1.6 FPLMTS should be designed to allow international operational operation and automatic roaming of mobile subscribers and stations. (The degree to which the roaming facility between networks or countries shall be automatic is not yet decided); 2.1.7 FPLMTS should be designed so that under favourable circumstances services requiring high information rates can be provided; 2.1.8 FPLMTS should be capable of providing service to a variety of mobile terminal ranging from those which are small enough to be easily carried on the person to those Which are mounted in a vehicle.
2.2 Bearer services
Lower bit rate channels (or sub-rate channels) are recommended for the FPLMTS equivalent of the ISDN B-channel and the D-channel.
2.2.1 Circuit-mode bearer services
In accordance which the appropriate CCITT Recommendations, subject to FPLMTS limitations.
2.2.2 Packet-mode bearer services
In accordance with the appropriate CCITT Recommendations, subject to FPLMTS limitations.
2.3 Teleservices
FPLMTS should support the teleservices listed below:
2.3.1 Telephony
In accordance with the appropriate CCITT Recommendations, subject to FPLMTS limitations.
2.3.2 Text
In accordance with the appropriate CCITT Recommendations, subject to FPLMTS limitations. 22 Rec. 687
2.3.3 Paging FPLMTS should be able to provide paging services, integrated with telephony and data services to the extent permitted by individual administrations. Mobile satellites may offer wide area paging beyond the range of terrestrial systems.
2.3.4 Videotex In accordance with the appropriate CCITT Recommendations, subject to FPLMTS limitations.
2.3.5 Facsimile In accordance with the appropriate CCITT Recommendations, subject to FPLMTS limitations.
2.3.6 Data " FPLMTS should provide synchronous and asynchronous data services which are offered on the PSTN, subject to the provision of additional error control facilities for the radio channel.
2.3.7 Short messages FPLMTS should allow the exchange of messages of limited length between a storage system connected to the fixed network and a station.
2.4 Supplementary services
In accordance with the appropriate CCITT Recommendations, subject to FPLMTS limitations.
2.4.1 Point-to-multipoint FPLMTS should provide this service for dispatch, group calling, closed user groups and other applications, to the extent permitted by individual administrations.
2.4.2 Separation o f answering from alerting FPLMTS should provide the capability for the user to answer on a network other than that on which he/she had been alerted.
2.4.3 Charging service FPLMTS should allow the capability of providing the paying party with the option of terminating a call to a roaming mobile if there is an extra charge. FPLMTS should offer the subscriber a supplementary service of having calls forwarded at his expense.
2.4.4 Location FPLMTS should be able to provide, in special situations, location information only to the extent permitted by competent authorities.
3. Frequency band considerations
3.1 General considerations . Considerations on spectrum should take into account the estimated traffic, the available and foreseeable techniques, the propagation characteristics and time scale for meeting the users needs to the greatest possible extent. Considerations on frequency matters should take into account the fact that to the end of the 20th century and after, the traffic generated by public mobile systems will continue to expand, as well as the number and diversity of services.
3.2 Traffic considerations
Any estimation of the traffic should take into consideration that in the future, non-voice traffic will constitute an increasing proportion of the total traffic and that traffic will be generated outdoors as well as indoors by mobile and personal stations. Rec. 687 23
3.3 Spectrum requirements
To comply with FPLMTS service requirements, namely the concept of regional and/or world-wide roaming, inclusion at least partly of world-wide common frequency allocations should be considered as the first choice to enable universal access particularly for personal stations. A sufficient allocation of spectrum should be made available for use around 1998 to fulfill the potential needs of FPLMTS around that date and beyond. ,
3.4 Technical and functional compatibility/commonality
Frequency commonality should allow for the desired level of operational compatibility on the system(s). In principle, a complete commonality of one frequency band on a world-wide basis would be desirable, but reasonable commonality could also be obtained through a common signalling band and sufficient overlap of the traffic bands to ensure compatibility. In order to facilitate the use of mobile satellite links with FPLMTS, the allocation of adjacent satellite and terrestrial bands should be considered.
3.5 Choice o f a frequency band
The cost and power efficiency of the RF technology available, the resulting consequences on FPLMTS hardware and on battery operating durations for portable and personal stations as well as the impact on cell structure, should be considered when choosing frequency bands. Overall propagation and RF technology factors indicate that the use of a band below 3 GHz would be suitable for FPLMTS.
3.6 State o f techniques
Estimation of spectrum needs should take into account the design of a system carrying traffic with high spectrum efficiency. To that effect speech and data transmissions should include good quality codecs associated with channel coding, modulation and equalization, multiple access techniques and adaptive techniques. Traffic management techniques such as queuing should also be considered since they may be very effective in smoothing the offered traffic load, and hence substantially increase spectrum utilization efficiency, particularly when services with differing characteristics including significant non-voice traffic are integrated into a common radio system.
3.7 Estimation o f spectrum needs
In an estimation of spectrum needs for voice services the total required bandwidth should range from approximately 160 MHz down to approximately 110 MHz according to possible technical solutions. In an evaluation of spectrum needs for non-voice services the total bandwidth should amount to 65 MHz. The total bandwidth therefore ranges from approximately 230 MHz (conservative projection of future technology) down to approximately 180 MHz (optimistic projection of future technology). This estimation should also take into account that in a number of countries an allocation of 50 MHz of spectrum below 1 GHz is used for existing cellular mobile systems. If these existing systems remain in service, the traffic they carry should be subtracted from the FPLMTS traffic assumptions. The need for new spectrum should range therefore from approximately 180 MHz (conservative projection) down to approximately 130-150 MHz (optimistic projection, depending on technology employed by existing systems below 1 GHz).
3.8 Studies to be undertaken
Studies should be undertaken so that spectrum could become available and sharing criteria determined with a view to satisfying the potential evolving needs of FPLMTS around 1998 and beyond. Such studies should take into account the possibility for FPLMTS to be an advanced system where control of the equipment will allow it to be adapted to various situations in particular by using dynamic power control and frequency agility (the ability to operate over a given frequency range).
4. Technical characteristics
In order to provide for regional and/or world-wide station compatibility, uniformity of main characteris tics including architecture, channel structure, control procedures, access techniques, modulation methods and data rates, should be applied. 24 Rec. 687
4.1 System architecture
FPLMTS should provide universal personal telecommunication services and should perform service origination and termination regardless of user location within the FPLMTS or PSTN/ISDN. The FPLMTS could be a part of the PSTN/ISDN or separate telecommunication networks. Therefore the Mobile Services Switching Centre (MSC) may be separate or integrated into the PSTN/ISDN. If more than one MSC is required to service a high traffic density location area, they should be able to work together to provide such service. In addition, the switching architecture should allow for handovers as frequent as may be necessary, without significant transmission impairments. Figure 1 illustrates the functional interfaces within FPLMTS and between FPLMTS and the PSTN/ISDN. These interfaces are intended to illustrate how the functions of the FPLMTS may be partitioned and do not imply an actual scenario for their implementation.
Radio link Y ,
a
10
FIGURE 1 - Major functional components and interfaces o f the FPLMTS
MS : mobile station PS : personal station BS : base station MSC : m obile services switching centre HLR : home location register VLR : visitor location register 1_10 : interfaces
FIGURE 1, p. Furthermore, each functional interface may represent a family of more specific interfaces. A possible scenario for the evolution and implementation of personal communications within FPLMTS, is given in Figs. 2 and 3. In these figures, the family of radio interfaces is: Rl: the radio interface between a mobile station (MS) and the base station (BS); R2: the radio interface between a personal station (PS) and the personal base station (CS); R3: the radio interface between the satellite and the Mobile Earth Station (MES). FPLMTS may also allow for the automatic routing of traffic between terrestrial and mobile satellite systems; R4: an additional radio interface used for alerting (e.g. paging) in the case of a call which is terminated at an FPLMTS terminal. In Fig. 2, Rl could be the same as R2 in some implementations. The generic radio link interface 1 of Fig. 1 could correspond to the sequence of interfaces mentioned above. It should be noted that this is not a complete list of all the interfaces. Taking into account the characteristics of areas where FPLMTS is introduced, the system structure should be optimized according to the geographical coverage areas and traffic conditions. Therefore, more than One radio interface should be allowed for in the design of systems. The radio interface should be designed to allow different applications to use the same interface where this can be shown to be technically and economically feasible. If the same radio interface cannot be used for all applications then the individual interfaces should have maximum commonality to allow interworking with the minimum of extra complexity. e. 687 Rec.
FIGURE 2 - Scenario for personal communications with FPLMTS (terrestrial component)
R1-R4: radio interfaces PBX private exchange PS personal station (R2) RP repeater CS : personal base station (cell site for PSs) PTN personal telecommunications MS : mobile station (R1-) PBS PAGIN BS base station (for MSs) PBS paging base station MSC : mobile services switching centre WP wide area pager (R4) LR location register telephone CX small rural exchange, etc.
(!) Access to and the scope of the location registration functions will vary with system evolution and network operator requirements. This is reflected in network interfaces A and B.
(2) In some implementation scenarios Rl may equal R2. 26 Rec. 687
CX MES
A or B
Aor B
R2
CS — |mes}“ Vehicle (private/public) W R2 land, maritime (2) or aeronautical (2 )
FIGURE 3 - Scenario for personal communications with FPLMTS (satellite component)
R1-R3: radio interfaces PS : personal station (R2) CS : personal base station (cell site for PSs) IVIES : mobile earth station SP : satellite pager (R3) MSC : mobile services switching centre SMSC : satellite mobile services switching centre LR : location register CX : small rural exchange, etc.
p : telephone
(!) Access to and the scope of the location registration functions will vary with system evolution and network operator requirements. This is reflected in network interfaces A and B.
(2) Terrestrial based systems have different radio interface requirements from R3 which need to be considered.
(3) Can be co-located/integrated with the PS. Rec. 687 27
4.1.1 Radio coverage o f the service area The aims of FPLMTS should be:
4.1.1.1 to accomodate the possibility of more than one base station in a service area; 4.1.1.2 to allow handover from one channel to another between cells, and in the same cell, if necessary; 4.1.1.3 to allow for implementation of small cell sizes taking account of the need for rapid handover for moving users; 4.1.1.4 to allow the re-use of the same channel assignment simultaneously by more than one cell and for more than one communication; 4.1.1.5 to be able to start with the fewest cells necessary to meet user demands and grow as necessary, with the possibility of increasing the availability of equipment for interconnection to the different system interfaces; > 4.1.1.6 to provide for adequate coverage to include portable units outdoors and in both single-storey and multi-storey buildings; 4.1.1.7 to minimize the complexity of any radio network planning taking into consideration radio propagation variations in different environments and locations.
4.1.2 Structure of signalling functions of Mobile Stations/Personal Stations (MS/PS) Among the logical signalling functions, either integrated or separated, the following should be provided by FPLMTS: — call control, — FPLMTS call control adaptation, — mobility management, — channel and RF transmission management.
4.1.3 Personnal Telecommunication Number (PTN) Service A PTN service to enable call connection, billing etc., on a user basis should be considered.
4.2 Quality o f service FPLMTS should provide a level of service quality comparable to the PSTN/ISDN within the limitations set by the radio channel. Determination of the quality of telecommunication service should include consideration of the following: — transmission quality: - S/N and S/I; — service area reliability; — blocking probability; — cut off probability, such as cut off probability due to handover blocking; — channel assignment strategies and call control thresholds; — handover; — initial connection delay; — system reliability.
4.3 Security FPLMTS should provide a level of security comparable to that of the PSTN/ISDN. If required, additional levels of encryption of user information could be offered. Any such facility should not have a significant influence on the costs of those parts of the system used by mobile subscribers who do not require such a facility. It should be possible for the users themselves to provide end-to-end encryption, subject to the technical limitations of the network. Protection should be provided to prevent unauthorized access to the system (authentication). Location information regarding mobile units should be subject to special safeguards (see also § 2.4.4 and 5.3).
4.4 Radio transmission considerations In order to improve performance, systems may adapt such parameters as channel bit rate, bandwidth, frequency/time/coding arrangements, diversity techniques and multipath equalization, to actual propagation, interference and traffic conditions, subject to cost and power consumption considerations. 28 Rec. 687
4.4.1 Multiple access techniques Voice and data services will be a basic part of FPLMTS and a flexible multiple access scheme is desirable to handle the wide range of traffic densities and services offered.
4.4.2 Modulation techniques When considered with frequency re-use factors, the modulation techniques should achieve efficient use of the spectrum. Technologies having transmission efficiencies greater than 1 bit/Hz should be used for FPLMTS.
4.4.3 Channel coding In order to maximize spectrum efficiency and transmission quality, channel coding should be utilized.
4.4.4 Source coding For speech, a transmission rate of 16 kbit/s or below is desirable. When choosing the speech transmission bit rate for mobile channels, consideration should be given to methods such as linear predictive coding, adaptive quantization and adaptive prediction as well as other factors affecting quality and spectrum efficiency.
4.5 Network aspects
4.5.1 The identification plan In accordance with the appropriate CCITT Recommendations.
4.5.2 The numbering plan In accordance with the appropriate CCITT Recommendations. In addition, the Personal Telecom munication Number (PTN) plan should be based on appropriate CCITT Recommendations.
4.5.3 Routing and billing rates System design should permit different charging and billing rates to be used in different networks.
4.5.4 Interconnection signalling system CCITT Signalling System No. 7 should be used for the interconnection signalling system in FPLMTS. ,
S. Operational characteristics
5.1 Call handling The following system functions which should take in account of the efficient use of the radio channel should apply to FPLMTS — channel assignment and set-up control procedures; — channel release at the completion and/or dropping of the call.
5.2 Supervision FPLMTS should perform those functions necessary to supervise channel status and to maintain the necessary quality.
5.3 , Location registration In accordance with CCIR Recommendation 624 and CCITT.Recommendations Q.1003 and Q.1004.
5.4 Network interworking FPLMTS should interwork with PSTN and ISDN in accordance with CCITT Recommendations Q.1031 and Q.1032. FPLMTS should provide the user with ISDN service transparency (within FPLMTS limitations). For details on FPLMTS compatibility with ISDN refer to Tables Land II. Rec. 687 29
T A B L E I — ISDN-FPLMTS compatibility (general)
ISDN FPLMTS (general)
D igital Digital at interface between FPLMTS and ISDN network (as a minimum) (interface 2 of § 4.1.2, Fig. 1).
Basic access (integrated voice and data) made up B channel functionality (flexible bit rate). For voice (at 2 B + D o f 2 B + D where 5= 64 kbit/s (Bearer channel) baseband) 32 kbit/s, more likely 16 kbit/s or lower; based on and D = 16 kbit/s (Signalling channel). spectrum and coding efficiency trade-offs.
C onsider B and D channels as information Compatible with ISDN D channel standards. D channel functionality content building blocks. may be spread over a number of radio channels depending on the multiple access techniques used.
For FPLMTS, I (information) and C (control) will be used in place o f B (bearer) and D (signalling) respectively, to signify the above differences within otherwise similar structures.
Error performance (64 kbit/s) is stated in Voice quality will be a function of the coding and channel error CCITT Recommendation G.821. This will be ratio. acceptable for data transmission (therefore very acceptable for speech). Source and channel coding may be optimized for speech. Acceptable error performance for data traffic on mobile radio channels is a subject for further study.
Bearer services at 64 kbit/s can be used to Extension of this capability to the mobile station would require support voice and data services. provision of up to 64 kbit/s through the FPLMTS.
Information on true user data rates to and from ISDN would make the provision of compatibility between FPLMTS and ISDN more efficient in spectrum usage.
TABLE II — ISDN-FPLMTS compatibility (specific)
FPLMTS (specific)
ISDN Mobile station/ Mobile PABX/ personal station mobile concentrator
Basic access (25+ D) 144 kbit/s 2 1 + C, 1 + C, C to 2 5 + D (N o te 1)
Primary access 1536 kbit/s (235+ D) or m /+ n C (N o te 2) 1920 kbit/s (305+ D)
N ote 1 — Full extent of ISDN basic access at 144 kbit/s (2 B + D ) could be provided by FPLMTS at the expense of reduced FPLMTS service availability due to the increased RF resource required to support such mobile use.
N ote 2 — The exact values for m and n are subject for further study. 30 Rec. 623
RECOMMENDATION 623
DATA TRANSMISSION BIT RATES AND MODULATION TECHNIQUES IN THE LAND MOBILE SERVICE
(Question 40/8) (1986) The CCIR,
CONSIDERING
(a) that digital signals are being increasingly used to improve communication efficiency in the land mobile service; (b) that benefits will result from standardization of data signalling bit rates conforming to CCITT Recommen dations V.5 and V.6 by facilitating the interworking of synchronous data transmission in the land mobile service with synchronous data transmission over telephone circuits; (c) that standardization of modulation techniques is one of the steps required for international interworking; (d) Report 903,
UNANIMOUSLY DECIDES \ 1. that the following data signalling bit rates should be preferred for synchronous data transmission in the land mobile service: 600, 1200, 2400, 4800 or 9600 bit/s (see Note 1);
2. that the following modulation techniques be preferred for constant envelope radio systems (see Notes 2 and 3), and that the FM deviation be adjusted so as to meet the spectral emission constraints of each administration:
2.1 Direct RF-carrier modulation technique (see Note 4): constant envelope modulation: GMSK, tamed FM, 4-state-FM, PLL-4-PSK.
2.2 Sub-carrier modulation technique:
Transmission bit rate Modulation Additional (see Note 3) method information . 1200 bit/s FFSK “0” = 1800 Hz; “1” = 1200 Hz 2400 bit/s FFSK “0” = 2400 Hz; “1” = 1200 Hz 4800 bit/s FFSK “0” = 4800 Hz; “1” = 2400 Hz 4800 bit/s bipolar
3. that due to fading on the radio channel some kind of error correction and retransmission should be used, resulting in a higher transmission bit rate than the data source bit rate. Note 1. — Other data transmission bit rates may be of interest (e.g. 6 kbit/s for 12.5 kHz channel spacing). This also may be the case when the system design does not require the same data rate on both the radio and telephone parts of the communication channel. Note 2: - For source bit rates up to 1200 bit/s sub-carrier data signals can pass through the speech processing circuits of the radio equipment and can be, in some cases, directly interconnected to the telephone network. For higher data signalling rates it may be necessary to provide separate data paths between the sub-carrier data signal and the RF-modulator and/or demodulator. Note 3. — For 9600 bit/s direct carrier modulation and for 4800 bit/s sub-carrier modulation, the necessary bandwidth may not be accommodated in a 12.5 kHz channel spacing scheme. Note 4. — There are a number of different direct modulation techniques which are not necessarily compatible (see Report 903). Rec. 624 31
RECOMMENDATION 624*
PUBLIC LAND MOBILE COMMUNICATION SYSTEMS LOCATION REGISTRATION
(Question 39/8) (1986) The CCIR,
CONSIDERING
(a) that interconnection of a roaming mobile station with a public switched network involves a knowledge of the location of the mobile station, together with the means of registering this information, so that appropriate routing and charging can be applied; (b) that the connection of calls to a roaming mobile station from a public switched network requires that technical and operational procedures for location registration be agreed and that this agreement is essential for international service; (c) that standardized procedures for location registration can provide benefits, particularly for roaming mobile stations which need to operate in more than one service area; (d) that the roaming mobile station may best determine when its location status needs to be up-dated,
UNANIMOUSLY RECOMMENDS , •
1. that the definitions given in Annex I should be used in connection with location registration;
2. that allocation of identities to location areas for transmission to the mobile station should be as follows:
LAI Cl
where: LAI: identification of a location area; Cl: identification of a cell within the location area if required for other purposes than location registration. The sequence LAI must also identify the country with which the location area is associated;
3. . that a mobile station should initiate a location registration procedure only when the sequence LAI received differs from the actual LAI information stored in the mobile station;
4. that the location registration procedure should be initiated by the mobile station and considered successful only when the registration is confirmed by the mobile services switching centre (MSC);
5. that the general procedures in the mobile station for location registration should be as shown in Fig. 4.
* The Director, CCIR, is requested to bring this Recommendation to the attention of the CCITT. 32 Rec. 624
ANNEX I
DEFINITIONS
For an extensive list of definitions to be used in connection with land mobile systems refer to CCITT Recommendation Q.70 (1984). In this Annex only definitions necessary for the understanding of the Recommen dation are included.
1. Mobile services switching centre (MSC)
In an automatic system, the mobile services switching centre (MSC) constitutes the interface between the radio system and the public switched networks (PSTN, PDN, ISDN). The MSC performs all necessary signalling functions in order to establish calls to and from mobile stations. A mobile station is registered at one MSC which functions as its home centre for charging and billing purposes and for administering its subscriber parameters such as category. In order to obtain radio coverage of a given geographical area, a number of base stations (radio transmitters/receivers) are normally required; i.e. each MSC would thus have to interface several base stations. In addition, several MSCs may be required in order to cover a country. The definition of the MSC may be prefixed by the term “land” or “maritime” if that is more suitable in a specific application.
2. Location register
To establish a call to a mobile station the network must know where this mobile station is located. This information is stored in a “location register”.
3. Location area
The location area is defined as an area in which a mobile station may move freely without updating the location register. A location area may comprise several base stations.
4. Location registration
Location registration is defined as the procedure by which details of the location of a mobile station are entered into a location register. ' The location register may be: — centralized, i.e. there is one common register for several MSCs (see Fig. 1); — distributed, i.e. there is a minimum of one location register assigned to each MSC (see Fig. 2); — segmented, i.e. the precise location of the mobile station can only be known after concatenation of fractional information distributed in a set of “partial” location registers (e.g. in a “hierarchical distribution” of location information (see Fig. 3).
FIGURE 1 - Centralized register Rec. 624 33
FIGURE 2 - Distributed system
\ \
PLR: partiaLlocation register
FIGURE 3 - Segmented location register 34 Rec. 624
5. Cell
The area covered by a base station or by a sub-system (sector antenna) of that base station corresponding to a specific logical identification on the radio path — whichever is smaller. Every mobile station in a cell can be reached by the corresponding radio equipment of the base station.
6. Base station area
The area covered by all the cells served by a base station.
7. Service area
The service area is defined as an area in which a mobile station is obtainable by a fixed subscriber in the PSTN, PDN or ISDN without the subscriber’s knowledge of the actual location of the mobile station within the area. A service area may consist of several public land mobile networks (PLMN, see CCITT Recommenda tion Q.70). One service area may consist of one country, be a part of a country or comprise several countries. The location registration system associated with each service area must thus contain a list of all mobile stations located within that service area. Note 1. — This definition does not take into account any constraints on routing imposed by the international telephone network. Fixed subscribers located within one.service area will, by definition, have access to all mobile stations within the area. However, for fixed subscribers located outside the area, such constraints may involve that the subscriber needs to know in which part of the service area the called mobile station is located, e.g. in which country, if the service area comprises more than one country. Note 2. — The service area may vary for interconnection of land mobile stations with different networks such as PSTN, PDN and ISDN.
8. Hand-off
Hand-off is the action of switching a call in progress from one cell to another cell. Hand-off is used to allow established calls to continue when mobile stations move from one cell to another cell. ANNEX II
FIGURE 4 - General procedures at the mobile station related to location registration PAGE INTENTIONALLY LEFT BLANK
PAGE LAISSEE EN BLANC INTENTIONNELLEMENT Rec. 585-2 37
SECTION 8B: MARITIME MOBILE SERVICE: TELEGRAPHY AND RELATED SUBJECTS
RECOMMENDATION 585-2
ASSIGNMENT AND USE OF MARITIME MOBILE SERVICE IDENTITIES (1982-1986-1990) The CCIR, , ■
CONSIDERING
(a) the need for a unique ship identity for safety and telecommunication purposes; (b) the need for this identity to be usable in automatic systems; (c) that, in the interest of having a common address format for automatic systems, identities assigned to ship stations, coast stations and used for establishing group calls should be of a similar nature when transmitted over the radio path; (d) Article 25 and Appendix 43 of the Radio Regulations; (e) that it is highly desirable that the code which forms the ship identity or part thereof can be used by subscribers to the public switched networks for calling ships automatically; (f) that the public switched networks in some countries have restrictions, with respect to the maximum number of digits that may be dialled or keyed to indicate ship station identity; (g) that CCITT Recommendation E.210/F.120 describes a ship station identification method which provides for this contingency; (h) that whatever restrictions may be required should, in the interests of the development of automatic shore-to-ship operations, be as few as possible,
UNANIMOUSLY RECOMMENDS ■1 1. that ships complying with the International Convention for the Safety of Life at Sea, 1974, as amended in 1988 and other ships equipped with automated radiocommunication systems, including Digital Selective Calling and/or carrying alerting devices of the Global Maritime Distress and Safety System should be assigned ship station identities in accordance with Annex I to this Recommendation;
2. that ship and coast stations using Morse telegraphy may continue to use existing alphanumeric call signs;
3. that ship and coast stations using digital selective-calling equipment in accordance with Recommenda tion 493 should use their 9-digit numerical identities transmitted as a 10-digit address/self-identity with a digit 0 added at the end of the identity;
4. that administrations issuing 5-digit numbers according to Radio Regulation No. 2134 should, if possible, assign 9-digit numerical identities and 5-digit numbers in such a way that there is a clear relation between them;
5. that the present octal numbering system in use in an existing maritime mobile-satellite system should be converted as early as feasible to a decimal system with 9-digit, ship station identities;
6. that any future international automatic maritime telecommunication system should be designed to use the 9-digit ship station identities on the radio path.
ANNEX I
ASSIGNMENT OF SHIP STATION IDENTIFICATION
1. Introduction
1.1 Ships participating in the maritime radio services mentioned in RECOMMENDS 1 shall be assigned a nine digit unique ship station identity in the format Mt 1203X4X5X5X7X3X9 wherein the first three digits represent the Maritime Identification Digits (MID). 1.2 Restrictions may apply with respect to the maximum number of digits which can be transmitted on some national telex and/or telephone networks for the purpose of ship station identification. 38 Rec. 585-2
1.3 At present, the maximum number of digits that are able to be transmitted over the national networks of many countries for the purpose of determining ship station identity is six. The digits carried on the network to represent the ship station identity is referred to as the “ship station number” in this text and in the relevant CCITT Recommendation. The use of the techniques described below should make it possible for the coast stations of such countries to engage in the automatic connection of calls to ship stations. 1.4 To obtain the required nine digit ship station identity a series of trailing zeros is added to the ship station number by the coast station for shore-originated automatic services, e.g.:
Ship station number Ship station identity
1^,1303X4X5X6 M,I2D3X4X5X6070809
2. As long as the restrictions in § 1 apply in one’s own network limiting ship station numbers to 6 digits, ships that intend to receive automatic network traffic from national coast stations only, should be assigned identities wherein X9, but not X8, = 0. This assumes that “9” is used to abbreviate the national MID for such ships for network purposes.
Ship station number ship station identity
9 X4X5X6X7X8 MnInDnX4X5X6X7X809
MnInDn are the Maritime Identification Digits of one’s own country. (See also § 3.2 of CCITT Recommendation E.210/F.120). If a country has more than one MID, only one may be used for this purpose.
3. As long as the restrictions in § 1 apply it may be useful for some administrations to expand the capacity for numerical ship station identification by using as many as ten “8 Y” abbreviations for MIDs. Such a technique may allow the assignment of ship station identities wherein trailing zeros are applied only to X8 and X9.
Ship station number Ship station identity
8 Y X4X5X6X7 M,I2P 3 X4X5X6X70809 The usefulness of this technique to a given administration may depend on whether its abbreviation (e.g. 83) of its own MID is duplicated in other administrations in which some of its ships have a community of interest. When such is the case the ship in question can be called using the same ship station number in all the automatic networks of interest to that ship. As an example, a group of up to ten countries, with community of interest, might agree to assign the same abbreviation for their respective MIDs. The abbreviation should always relate to the numerically lowest MID, when more than one is assigned to a given country.
Country “8 Y” Assignment
A 80 B 81 C 82 D 83 E 84 (All countries recognize a particular 8 Y abbreviation F 85 as associated with a particular country) G 86 H 87 I 88 J 89 For example a coast station in any of the countries A to J receiving “83” as the first two digits of a ship station number would transmit the MID of country D.
4. As long as the restrictions in § 1 apply, ships that require regular automatic communications from foreign coast stations additional to those that may conform to the abbreviation arrangement noted in § 3 shall only be assigned ship station identities with X7X8X9 = 000 to support 6 digit ship station numbers. Rec. 585-2 39
5. When it becomes necessary to progress to stage 2, (seven digit ship station numbers for automatic shore-originated traffic) in the ship station identity scheme the format of ship station identities in § 4 would change from M1I2D3X4X5X6O7O8O9 to M1I2D3X4X5X6X7O8O9. If “8 Y” abbreviations are used in stage 1 (six digit ship station numbers for automatic shore-originated traffic) some ship station identify assignments will already have taken the M1I2D3X4X5X6X7O8O9 format. It would therefore be useful to reserve at least one value in the X7 digit position if ship station identity assignments are made on the basis of “8 Y” network abbreviations:
Ship station number Ship station identity 8 Y X4X5X6X7 . M ,1203X4X5X5X70309
stations only stations additional to (see § 2) “8 Y” abbreviations of those which may have the MID (see § 3) appropriate “8 Y ” abbre viations of the M ID (see § 4 )
Assign 9 digit Assign 9 digit Assign 9 digit ship Assign 9 digit ship ship station ship station station identity with station identity with identity with identity with X 8X9 = 00 X7X8X9 = 000 X 9 * 0 X 9 = 0
FIGURE 1 - Procedure for selecting numerical ship station identities as long as network restrictions apply
N ote. - “Manual” refers to manual operation in the terrestrial telecommunication networks. 40 Rec. 218-2
RECOMMENDATION 218-2
PREVENTION OF INTERFERENCE TO RADIO RECEPTION ON BOARD SHIPS (1951-1956-1974-1990) The CCIR,
CONSIDERING
(a) that the Maritime Regional Radio Conference, Copenhagen, 1948, recommended that the CCIR study the question of interference to radio reception caused by electrical installations on board ship; (b) that the International Convention for the Safety of Life at Sea, 1974, as amended in 1988, requires that every radio installation shall be so located that no harmful interference of mechanical, electrical or other origin affects its proper use; (c) that electrical interference is generally caused by the unwanted excitation of the radio receiving equipment, including the antenna, by fluctuating electromagnetic fields set up by other electrical installations; (d) that the fluctuation of electromagnetic fields, which'gives rise to interference, is caused by abrupt changes in current in the source of interference, and by abrupt changes in the resistance of conductors situated in electromagnetic fields; (e) that electrical interference may be transmitted by direct radiation and induction from the source of interference itself, and also by radiation, re-radiation and induction from conductors which carry interfering currents, ^
UNANIMOUSLY RECOMMENDS
1. that the design, construction and installation of electrical equipment on ships should be such that interference is minimized at its source (see No. 3600, 4100, 5131 of the Radio Regulations);
2. that electrical equipment installed in ships should be properly maintained to prevent any increase in the level of interference which it causes;
3. that antennas used for transmission or reception should be erected as far above and as far away as possible from electrical machinery and from parts of the ship’s structure such as funnels, stays and shrouds;
4. that the feeders of antennas which are used exclusively for reception should be screened; that the screen should extend continuously from the receiver to a point which is as high as practicable above the ship’s structure, and that the screen should be effectively earthed;
5. that the frame or loop antennas used for direction-finding, should be effectively screened against electrostatic interference;
6. that radio receiving equipment should be sited in a room specifically provided for the purpose. This room should be effectively screened and situated as high as practicable in the ship;
7. that where a room cannot be provided specifically for radio equipment then the space provided should be as far away as possible from all sources of interference and situated as high as practicable in the ship;
8. that the radio receiving equipment should be designed so that it is effectively screened and protected against conducted interference;
9. that suppressor filters, intended to reduce to an acceptable level the interference which is propagated, should be fitted at the sources of interference, preferably being built into equipment producing the interference, and that in particular: 9.1 the electrical ignition systems of internal combustion engines, including those which may be installed in life-boats, should be fitted with suppressors; 9.2 the navigational instruments and other electronic equipment, should, if necessary, be .fitted with suppres sors, be screened, and the screen effectively earthed; 9.3 the necessary degree of suppression should be determined taking into account: — the susceptibility to interference of the receiver, and the coupling between the ship’s electrical installation and the receiving antennas; Rec. 218-2 41
10. that cables in the vicinity of the receiving antennas or the radio receiving room, and cables within the radio room, should be screened by enclosing them in metal conduits, unless the cables themselves are effectively screened;
11. that “lead” and “return” conductors should be in the same cable to avoid the formation of current loops. The metal structure of the ship should not be used for carrying current;
12. that suppressors should be fitted to cables at their point of entry into the radio receiving room;
13. that cables, ducts and pipes which do not terminate in the radio receiving room, should preferably not be routed through the radio receiving room; if it is essential for them to pass through the radio receiving room, the ducts and pipes and the screening of the cables should be effectively earthed;
14. that all radio, electrical and electronic apparatus in the radio receiving room should be effectively connected to the metal structure of the ship in the shortest possible way, and that the screens of all cables in the ship should be properly earthed;
15. that rigging should be either deliberately insulated from or bonded to the ship’s structure (stays that are subject to considerable tension can more conveniently be bonded);
16. that for smaller vessels, vessels without specific radio receiving rooms, and those constructed of non conducting materials, the principles recommended should be applied as far as is practicable;
17. that particular care should be taken to minimize interference on the frequency bands used for distress, safety and radionavigation in the maritime service; ,
18. that administrations should bring the above recommendations to the attention of naval architects, shipbuilders, those responsible for the construction, installation and maintenance of electrical, electronic and radio equipment and those organizations responsible for the formulation of standards. 42 Rec. 625-1
RECOMMENDATION 625-1 *
DIRECT-PRINTING TELEGRAPH EQUIPMENT EMPLOYING AUTOMATIC IDENTIFICATION IN THE MARITIME MOBILE SERVICE**
(Question 5/8) (1986-1990) The CCIR,
CONSIDERING
(a) the there is a requirement to interconnect ship stations or ship stations and coast stations, equipped with start-stop apparatus employing the International Telegraph Alphabet No. 2, by means of radiotelegraph circuits; (b) that direct-printing telegraph equipment in the maritime mobile service is used for: — telex and/or telegraph service between a ship station and a subscriber of the (international) telex network; — telegraph service between a ship station and a coast station or between two ship stations; — telegraph service between a ship station and an extended station (ship owner) via a coast station; — telegraph service in a broadcast mode from a coast station, or a ship station, to one or more ship stations; (c) that the broadcast mode cannot take advantage of an ARQ method, as a return path is not used; (d) that for the broadcast mode a forward error-correcting (FEC) method should be used; .(e) that the period for synchronization and phasing should be as short as possible; (f) that most of the ship stations do not readily permit the simultaneous use of radio transmitter and receiver; (g) . that a direct-printing telegraph system employing error-detecting and error-correcting methods in accord ance with Recommendation 476, is in actual operation; (h) that the increased use of direct-printing telegraph equipment has emphasized the importance of an unambiguous identification of both stations when a circuit is established or re-established; (j) that unambiguous identification could be accomplished by the exchange of self-identification signals between the ARQ equipments at the 7-unit level; (k) that Appendix 43 of the Radio Regulations, CCIR Recommendation 585 and CCITT Recommenda tions E.210 and F.120 provide for a comprehensive system of assigning maritime mobile service identities; (I) that, in the interest of having a unique identity assigned to each ship station for distress and safety and other telecommunication purposes, the address capability should allow the use of maritime mobile service identities in accordance with the provisions of Appendix 43 of the Radio Regulations; (m) that equipment built in accordance with Recommendation 476 cannot provide for the use of maritime mobile service identities mentioned in CONSIDERING (k); (n) that there is a need to provide for compatibility to the extent possible with equipments built in accordance with Recommendation 476; however, unambiguous identification of both stations cannot be achieved when circuits are established with equipments built in accordance with Recommendation 476,
UNANIMOUSLY RECOMMENDS
1. that for direct-printing telegraph circuits in the maritime mobile service, a 7-unit ARQ method should be employed;
2. that for the direct-printing telegraph service in the broadcast mode, a 7-unit forward acting error-correcting method, using time diversity, should be employed;
3. that equipment designed in accordance with RECOMMENDS 1 and 2 should employ automatic identifica tion and hqve the characteristics given in Annex I.
* The Director, CCIR is requested to bring this Recommendation to the attention of the IMO and the CCITT. ** Newly developed equipment should conform to Recommendation 625 which provides for compatibility with existing equipment built in accordance with Recommendation 476. Rec. 625-1 43
ANNEX I
CONTENTS
Page
1. General (mode A (ARQ) and mode B (F E C )) ...... 44
2. Conversion tables...... 44 2.1 General ...... 44 2.2 Traffic information signals ...... 45 2.3 Service information s ig n a ls ...... 45 2.4 Identification and check-sum numbers and signals...... 45 2.5' Check-sum signal derivation...... 46
3. Characteristics, mode A (ARQ) ...... 47 3.1 G eneral...... 47 3.2 Master and slave arrangem ents...... 47 3.3 The information sending station (ISS) , ...... 47 3.4 The information receiving station (IR S)...... 47 3.5 Phasing procedure ...... 47 3.6 Automatic identification ...... 49 3.7 Traffic flo w ...... 50 3.8 Rephasing procedure ...... 3.9 Summary of service blocks and service information signals ...... 53
4. Characteristics, mode B (FEC) ...... 53 4.1 General ...... 53 4.2 The sending station (CBSS and SBSS)...... l...... 53 4.3 The receiving station (CBRS and SBRS) ...... 53 4.4 Phasing procedure ...... 54 4.5 Selecting calling procedure (selective B-mode) ...... 54 4.6 Traffic flow ...... 54 Appendix I SDL diagrams (mode A ) ...... 65 Appendix II Phasing procedure with automatic identification in the case of a 7-signal call identity (calling station) ...... 68 Appendix III Rephasing procedure with automatic identification in the case of a 7-signal call identity (calling station) . .'...... 71 Appendix IV Phasing procedure without automatic identification in the case of a 4-signal call identity (calling station) ...... 74 Appendix V Rephasing procedure without automatic identification in the case of a 4-signal call identity (calling station)...... 75 Appendix VI Phasing procedure with automatic identification in the case of a 7-signal call identity (called station) ...... 76 Appendix VII Rephasing procedure with automatic identification in the case of a 7-signal call identity (called station) ...... ! ...... 79 Appendix VIII Phasing procedure without automatic identification in the case of a 4-signal call identity (called station)...... 82 Appendix IX Rephasing procedure without automatic identification in the case of a 4-signal call identity (called station)...... 83 Appendix X Traffic flow in the case of a 4-signal call identity and in the case of a 7-signal call identity (station is in the ISS position) ...... 84 Appendix XI Traffic flow in the case of a 4-signal call identity and in the case of a 7-signal call identity (station is in the IRS position)...... 87 44 Rec. 625-1
Appendix XII State overview diagram s ...... 89 Sheet 1 — Phasing procedure with automatic identification in the case of a 7-signal call identity (calling station) and traffic flow if the station is in the ISS position...... 89 Sheet 2 — Rephasing procedure with automatic identification in the case of a 7-signal call identity (calling station) and traffic flow if the station is in the ISS p o sitio n ...... 90 Sheet 3 — Phasing procedure without automatic identification in the case of a 4-signal call identity (calling station) and traffic flow if the station is in the ISS position ...... 91 Sheet 4 — Rephasing procedure without automatic identification in the case of a 4-signal call identity (calling station) and traffic flow if the station is in the ISS p o sitio n ...... 92 Sheet 5 — Phasing procedure with automatic identification in the case of a 7-signal call identity (called station) and traffic flow if the station is in the IRS position ...... 93 Sheet 6 — Rephasing procedure with automatic identification in the case of a 7rsignal call identity (called station) and traffic flow if the station is in the IRS position . 94 Sheet 7 — Phasing procedure without automatic identification in the case of a 4-signal call identity (called station) and traffic flow if the station is in the IRS position ..... 95 Sheet 8 — Rephasing procedure without automatic identification in the case of a 4-signal call identity (called station) and traffic flow if the station is in the IRS position . 96
1, General (mode A (ARQ) and mode B (FEC))
1.1 The system is a single-channel synchronous system using the 7-unit constant ratio error-detecting code as listed in § 2.2 and 2.3. 1.2 The modulation rate on the radio link is 100 Bd. The equipment clock controlling the modulation rate should have an accuracy of 30 parts in 106 or better. 1.3 The frequency shift on the radio link is 170 Hz. When frequency shift is effected by applying audio signals to the input of a transmitter, the centre frequency of the audio spectrum applied to the transmitter should be 1700 Hz. 1.4 The radio-frequency tolerance of the transmitter and the receiver should be in accordance with Appendix 38 of the Radio Regulations. It is desirable that the receiver employs the minimum practicable bandwidth (see also Report 585). Note. — The receiver 6 dB bandwidth should preferably be between 270 and 340 Hz. 1.5 For direct connection to the international telex network, the line input and output signals should be in accordance with the 5-unit start-stop International Telegraph Alphabet No. 2, at a modulation rate of 50 Bd. 1.6 Equipment designed in accordance with this Recommendation is likely to contain high speed digital circuitry. Special care should be taken to avoid interference to other equipment and to minimize susceptibility to interference from other equipment or electrical lines on board ship (see also Recommendation 218). 1.7 When operating in mode A (ARQ), the called station employs a constant time interval between the end of the received signal and the start of the transmitted signal (tE in Fig. 1, § 3.2.5). In the case of long propagation distances it is essential to have this tE as short as practicable. However, in the case of short distances it may be desirable to introduce a longer time interval, e.g. 20-40 ms, to accommodate receiver desensitization at the calling station. This time interval can be introduced at the called station either in the ARQ equipment or in the radio equipment.
2. Conversion tables
2.1 General
Several kinds of “signals” are used in the system, such as: — traffic information signals, , — service information signals (control signals, idle signals, signal repetition), — identification signals, — check-sum signals. Rec. 625-1 45
2.2 Traffic information signals These signals are used during communication to convey the message information which is passed from an information sending station to one or more information receiving stations. Table I lists the traffic information signals which may be used.
T A B L E I
Traffic information signals International C om bi- Transmitted Telegraph nation- 7-unit Alphabet No. 2 N o. Letter- Figure- signal (2) case case C od e (')
1 A ZZAAA BBBYYYB 2 B ? ZAAZZ YBYYBBB 3 C AZZZA BYBBBYY 4 D H (3) ZAAZA BBYYBYB 5 E 3 ZAAAA YBBYBYB 6 F (4) ZAZZA BBYBBYY 7 G (4) AZAZZ BYBYBBY 8 H (4) AAZAZ BYYBYBB 9 I 8 AZZAA BYBBYYB
10 J j l (Audible signal) ZZAZA BBBYBYY 11 K ( ZZZZA YBBBBYY 12 L ) AZAAZ BYBYYBB 13 M AAZZZ BYYBBBY 14 N AAZZA BYYBBYB 15 O 9 AAAZZ BYYYBBB 16 P 0 AZZAZ BYBBYBY 17 Q 1 ZZZAZ YBBBYBY 18 R 4 AZAZA BYBYBYB 19 S - ’ ZAZAA BBYBYYB 20 T 5 AAAAZ Y Y B Y B B B v 21 u 7 ZZZAA YBBBYYB 22 V = AZZZZ YYBBBBY ' 23 w 2 ZZAAZ BBBYYBY 24 X / ZAZZZ YBYBBBY 25 Y 6 ZAZAZ BBYBYBY 26 z + ZAAAZ BBYYYBB 27 «- (Carriage return) AAAZA YYYBBBB 28 = (Line feed) AZAAA YYBBYBB 29 J, (Letter shift) ZZZZZ YBYBBYB 30 | (Figure shift) ZZAZZ YBBYBBY 31 A (Space) AAZAA YYBBBYB 32 □ No information AAAAA YBYBYBB
(') A represents start polarity, Z represents stop polarity (see also Recommendation 490). (2) B represents the higher emitted frequency and Y the lower (see also Recommendation 490).
(3) The pictorial representation shown is a schematic of 4* which may also be used when equipment allows (CCITT Rec. F.l, § C9).
(4) At present unassigned (see CCITT Rec. F.l, § C8). Reception of these signals, however, should not initiate a request for repetition.
2.3 Service information signals These signals are used to control the procedures taking place over the radio circuit and do not form part of the transmitted messages. Service information signals are not normally printed or displayed. Table II lists the service information signals which may be used.
2.4 Identification and check-sum numbers and signals Identification and check-sum numbers and signals are used in the automatic identification procedure in order to provide a means by which, during the establishment or re-establishment of a radio circuit, the stations concerned are Clearly and unambiguously identified to each other. The relationship between the transmitted identification signals and their equivalent numbers is shown in Table Ilia; Table IHb indicates the conversion from check-sum numbers to the transmitted check-sum signals. I 46 Rec. 625-1
T A B L E II
Mode A (ARQ) Transmitted signal Mode B (FEC)
Control signal 1 (CS1) BYBYYBB Control signal 2 (CS2) YBYBYBB * Control signal 3 (CS3) BYYBBYB Control signal 4 (CS4) B Y B Y B B Y , Control signal 5 (CS5) BYYBYBB Idle signal [3 BBYYBBY Idle signal P Idle signal a BBBBYYY Phasing signal l, Idle signal a Signal repetition (RQ) YBBYYBB Phasing signal 2
TABLE Ilia TABLE Illb
Identification E quivalent C heck-sum C heck-sum signal num ber num ber signal (IS) • (N ) ■ (C N ) (CK)
A 19 0 V B 11 1 X C 6 2 Q D 18 3 K E 13 4 M F 8 5 P I 15 6 C K 3 7 Y M 4 8 F O 14 9 S P 5 10 T Q 2 11 B R 16 12 U S 9 13 E T . 10 14 0 U 12 15 I V 0 16 R X 1 17 Z Y 7 18 D Z 17. 19 A
2.5 Checksum signal derivation
These identification signals IS1, IS2, IS3, IS4, IS5, IS6 and IS7 are converted into their equivalent numbers N l, N2, N3, N4, N5, N6 and N7 respectively, in accordance with Table Ilia. The three numbers Nl, N2 and N3 are added and the sum is translated into one check-sum number CN1 using modulo 20-addition. This process is repeated for the numbers N3, N4 and N5 resulting in a check-sum number CN2 and for the numbers N5, N6 and N7 resulting in a check-sum number CN3, as follows: N l © N2 © N3 = CN1 N3 © N4 © N5 = CN2 N5 © N6 © N7 = CN3 where © denotes modulo 20-addition. The last conversion is from check-sum numbers CN1, CN2 and CN3 into “check-sum signal 1”, “check-sum signal 2” and “check-sum signal 3” respectively, in accordance with Table Illb. Rec. 625-1 47
Example: The seven idenfication signals of station 364775427 are: P E A R D B Y (see Recommendation 491). The check sum derivation will be as follows: P E A R D B Y -*► 5 13 19 16 18 11 5 © 13 © 19 17 (37-20) 19 © 16 © 18 = 13 (53-20-20) 18 © 11 © 7 16 (36-20) 17 13 16 —► Z E R where © denotes modulo 20-addition.
Result: CK1 becomes “Z” (combination No. 26, see Table I) CK2 becomes “E” (combination No. 5, see Table I) CK3 becomes “R” (combination No. 18, see Table I)
3. Characteristics, mode A (ARQ)
3.1 General The system operates in a synchronous mode transmitting blocks of three signals from an information sending station (ISS) towards an information receiving station (IRS). A control signal is transmitted from the IRS to the ISS after reception of each block indicating correct reception or requesting retransmission of the block. These stations can interchange their functions.
3.2 Master and slave arrangements
3.2.1 The station that initiates the establishment of the radio circuit (the calling station) becomes the “master” station, and the station being called will be the “slave” station. This situation remains unchanged during the entire time that the established radio circuit is maintained, regardless of which station, at any given time, is the information sending station (ISS) or the information receiving station (IRS). 3.2.2 The clock in the master station controls the timing of the entire circuit (see circuit timing diagram. Fig. 1). This clock should have an accuracy of 30 parts in 106 or better. 3.2.3 The basic timing cycle is 450 ms and consists for each station of a transmission period followed by a transmission pause during which reception is effected. 3.2.4 The master station transmit timing is controlled by the clock in the master station. 3.2.5 The clock controlling the timing of the slave station is phase-locked to the signal received from the master station, i.e. the time interval between the end of the received signal and the start of the transmitted signal'(t£ in Fig. 1) is constant (see also § 1.7). 3.2.6 The master station receive timing is phase-locked to the signal received from the slave station.
3.3 The information sending station (ISS)
3.3.1 The ISS groups the information to be transmitted into blocks of three signals (3x7 signal elements). 3.3.2 The ISS sends a block in 210 ms (3 x 70 ms) after which a transmission pause of 240 ms becomes effective.
3.4 The information receiving station (IRS)
3.4.1 After the reception of each block the IRS sends one signal of 70 ms duration (7-signal elements), after which a transmission pause of 380 ms becomes effective.
3.5 Phasing procedure
3.5.1 When no circuit is established, both stations are in the “stand-by” condition. In this condition neither Of the stations is designated master, slave, ISS or IRS. 3.5.2 The “calf signal” contains either four or seven identification signals as applicable. The identifica tion signals are listed in Table Ilia. The composition of these “call signals” should be in accordance with Recommendation 491. 3.5.2.1 The equipment should be capable of operating with both 4-signal and 7-signal identity procedures and automatically employing the appropriate procedure for either, as indicated by the composition of the “call signal” received from a calling station or by the number of digits (4, 5 or 9) supplied to the. equipment of a calling station to identify the station to be called. 48 Rec. 625-1
Master station Slave station
J L ' k E o Master station ISS, *— Information block CM, f Slave station IRS
Control signal
Information block
*!/>▲ 1 j i E *
Control signal Slave station ISS, Master station IRS
Information block
FIGURE 1 - Basic tim ing diagram
tp : (one-way) propagation time tj? : equipment delay (see also § 1.7)
3.5.3 The “call signal” contains: — in “call block 1”: in the first, second and third character places respectively: the first identification signal, the service information signal “signal repetition” and the second identification signal of the called station; — in “call block 2”: in the first, second and third character places respectively, either: - in the case of a 4-signal call identity: the third and the fourth identification signals of the called station and “signal repetition”; or - in the case of a 7-signal call identity: “signal repetition”, and the third and fourth identification signals of the called station; • — in the case of a 7-signal call identity in “call block 3”: (he last three identification signals of the called station. 3.5.4 The station required to establish the circuit becomes the master station and sends the “call signal” until it receives an appropriate control signal; however, if the circuit has not been established within 128 cycles (128 x 450 ms), the station changes into the “stand-by” condition and waits for a time of at least 128 cycles before sending the same “call signal” again. 3.5.5 The called station becomes the slave station and changes from the “stand-by” to the IRS condition: — in the case of a 4-signal call identity following the consecutive reception of “call block 1” and “call block 2”, after which it sends ‘‘Control signal 1” until the first information block has been received;
— in the case of a 7-signal call identity following the reception of the three call blocks in succession after which it sends “control signal 4” until “identification block 1 ” has been received. \ Rec. 625-1 49
3.5.6 On receipt of two consecutive identical signals “control signal 1” or “control signal 2” the calling station changes to the ISS condition and proceeds directly with the transmission of traffic information (see - § 3.7) without automatic identification. Note. — Equipment built in accordance with Recommendation 476 sends “control signal 1” or “control signal 2” on receipt of the appropriate “call signal”. 3.5.7 On receipt of “control signal 3” during the phasing procedure, the calling station immediately changes to the “stand-by” condition, and waits 128 cycles before sending the same “call signal” again. Note. — Equipment built in accordance with Recommendation 476 may send “control signal 3” on receipt of the appropriate “call signal”, if the called station is rephasing and was in the ISS condition at the moment of interruption. 3.5.8 On receipt of “control signal 5” during the phasing procedure, the calling station starts the “end-of-communication” procedure in accordance With § 3.7.14, and waits at least 128 cycles before sending the same “call signal” again. During this waiting time the station is in the “stand-by” condition.
3.6 Automatic identification
Only applicable in the case of a 7-signal call identity. 3.6.1 On receipt of “control signal 4” the calling station changes to the ISS condition and starts the identification procedure. During the identification cycle, information is exchanged about the identities of both stations; the ISS transmits its identification blocks and the IRS returns the check-sum signals derived from its identity in accordance with § 2.5. On receipt of each check-sum signal, the calling station compares this signal with the appropriate check-sum signal locally derived from the identification signals transmitted in the call blocks. If they are identical, the calling station continues with ,the following procedure, otherwise the procedure of § 3.6.12 is followed. 3.6.2 The ISS sends “identification block 1” containing its own first identification signal, “idle signal a” and its second identification signal in the first, second and third character places respectively. 3.6.3 On receipt of “identification block 1” the called station sends “check-sum signal 1”, derived from its identity. 3.6.4 On receipt of “check-sum signal 1” the calling station sends “identification block 2” containing the first, second and third character places respectively, “idle signal a”, its third identification signal and its fourth identification signal. 3.6.5 On receipt of “identification block 2” the called station sends “check-sum signal 2”, derived from its identity. 3.6.6 On receipt of “check-sum signal 2” the calling station sends “identification block 3” containing its fifth, sixth and seventh identification signals in the first, second and third character places respectively. 3.6.7 On receipt of “identification block 3” the called station sends “check-sum signal 3”, derived from its identity. 3.6.8 On receipt of the last check-sum signal the calling station sends the “end -of-identification block” containing three “signal repetition” signals. 3.6.9 On receipt of the “end-of-identification block” the called station sends, either: - “control signal 1”, thus starting the traffic flow in accordance with § 3.7; or - “control signal 3”, if the called station is required to start the traffic flow in the ISS condition (in accordance with § 3.7.11). 3.6.10 On receipt of “control signal 1” the calling station ends the identification cycle and starts the traffic flow by transmitting “information block 1” in accordance with § 3.7. 3.6.11 On receipt of “control signal 3” the calling station ends the identification cycle and starts the traffic flow with the change-over procedure in accordance with § 3.7.11. 3.6.12 If any received check-sum signal is not identical to the locally derived check-sum signal, the calling station retransmits the previous identification block. On receipt of this identification block, the called station sends the appropriate check-sum signal once more. On receipt of this check-sum signal the calling station compares again. If they are still not identical, and the received check-sum signal is the same as the previous one, the calling station initiates the “end of communication” procedure in accordance with § 3.7.14; otherwise the calling station transmits the previous identification block again. Any identification block should not be retransmitted more than four times due to reception of wrong check-sum signals, after which, if the required check-sum signal is still not received, the calling station reverts to the “stand-by” condition. 50 Rec. 625-1
3.6.13 If, due to mutilated reception, the calling station does not receive: — “control signal 4”, it continues transmitting the “call signal”; — “check-sum signal 1”, it retransmits “identification block 1”; — “check-sum signal 2”, it retransmits “identification block 2”; — “check-sum signal 3”, it retransmits “identification block 3”; — “control signal 1” or “control signal 3”, it retransmits the “end-of-identification block”, taking into account the time limit mentioned in § 3.6.18. 3.6.14 If, due to mutilated reception, the called station does not receive a block during the identification cycle, it transmits a “signal repetition”, taking into account the time limit mentioned in § 3.6.18. 3.6.15 If during the identification cycle the calling station receives a “signal repetition”, it retransmits the previous block. 3.6.16 If, due to retransmission of an identification block by the calling station, the identification signals as received by the called station are not identical, the called station sends “signal repetition” until two identical consecutive identification blocks are received after which the corresponding check-sum signal is transmitted, taking into account the time limit mentioned in § 3.6.18. 3.6.17 If during the identification cycle the called station receives the “end-of-communication block” (containing three “idle signals a”), it sends a “control signal 1” and reverts to the “stand-by” condition. 3.6.18 When reception of signals during the identification cycle is continuously mutilated, both stations revert to the “stand-by” condition after 32 cycles of continuous repetition. 3.6.19 Each station should retain the identity of the other station for the duration of the connection (see § 3.7.1) and this information should be accessible locally, e.g. by means of a display or on a separate output circuit for external use. However, this identity information should not appear on the output line to the network.
3.7 Traffic flow
3.7.1 At all times after the start of the traffic flow and until the station reverts to the “stand-by” condition, the station should retain the following information: — whether it is in the master or slave condition; — the identity of the other station (when applicable); — whether it is in the ISS or IRS condition; — whether the traffic flow is in the letter case or figure case condition. 3.7.2 The ISS transmits the traffic information in blocks, each block consisting of three signals. If necessary, “idle signals P” are used to complete or to fill information blocks when no traffic information is available. 3.7.3 The ISS retains the, transmitted information block in memory until the appropriate control signal confirming correct reception by the IRS has been received. 3.7.4 For internal use, the IRS numbers the received information blocks alternately “information block 1” and “information block 2” dependent on the first transmitted control signal. The numbering is interrupted at the reception of, either: — an information block in which one or more signals are mutilated; or — an information block containing at least one “signal repetition”. 3.7.5 The IRS sends “control signal 1” at the reception of, either: — an unmutilated “information block 2” ; or — a mutilated “information block 1” ; or — an “information block 1” containing at least one “signal repetition”. 3.7.6 The IRS sends “control signal 2” at the reception of, either: — an unmutilated “information block 1” ; or — a. mutilated “information block 2”; or — an “information block 2” containing at least one “signal repetition”. 3.7.7 For internal use, the ISS numbers successive information blocks alternately “information block 1” and “information block 2”. The first block should be numbered “information block 1” or “information block 2” dependent on whether the received control signal is a “control signal 1” or a “control signal 2”. The numbering is interrupted at the reception of, either: — a request for repetition; or — a mutilated control signal; or — a “control signal 3”. Rec. 625-1 51
3.7.8 On receipt of “control signal 1” the ISS sends “information block 1”. 3.7.9 On receipt of “control signal 2” the ISS sends “information block 2”. 3.7.10 On receipt of a mutilated control signal the ISS sends a block containing three “signal repetitions”.
3.7.11 Change-over procedure
3.7.11.1 If the ISS is required to initiate a change in the direction of the traffic flow, the station sends the signal sequence (“f” combination No. 30), “ + ” (combination No. 26), “?” (combination No. 2)followed, if necessary, by one or more “idle signals P” to complete the information block. 3.7.11.2 On receipt of the signal sequence (“ + ”, “?” (combination No. 26 and combination No. 2)) with the traffic flow in the figure case condition, the IRS sends “control signal 3” until an information block containing the signals “idle signal P”, “idle signal a ”, idle signal P” has been received. Note. — The presence of “idle signals P” between the signals “ + ” and “?” should not inhibit the response of the IRS. 3.7.11.3 If the IRS is required to initiate a change in the direction of the traffic flow, it sends “control signal 3”. , 3.7.11.4 On receipt of “control signal 3” the ISS sends an information block containing “idle signal P”, idle signal a ” and “idle signal P” in the first, second and third character places respectively. 3.7.11.5 On receipt of the information block containing the service information signals “idle signal P”, “idle signal a ” and “idle signal P”, the IRS changes to ISS and sends, either: — an information block containing three “signal repetitions”, if it is the slave station; or — one “signal repetition”, if it is the master station, until either “control signal 1 ” or “control signal 2” is received, taking into account the time limit mentioned in § 3.7.12.1. 3.7.11.6 The ISS changes to IRS after the reception of, either: — an information block containing three “signal repetitions” if it is the master station; or — one “signal repetition” if it is the slave station, and sends either “control signal 1” or “control signal 2” depending on whether the preceding control signal was “control signal 2” or “control signal 1”, respectively, after, which the traffic flow starts in the appropriate direction. 1
3.7.12 Time-out procedure
3.7.1211 When reception of information blocks or of control signals is continuously mutilated, both stations revert to the “rephase” condition after 32 cycles of continuous repetition, in accordance with § 3.8.
3.7.13. Answer-back procedure
3.7.13.1 If the ISS is required to request terminal identification, the station sends the signals “f” (combination No. 30) and “El” (combination No. 4) followed, if necessary, by one or more “idle signals p” to complete the information block. 3.7.13.2 On receipt of an information block containing the traffic information signal “E ” (combination No. 4) with the traffic flow in the figure case condition, the IRS: — changes the direction of the traffic flow in accordance with § 3.7.11; — transmits the traffic information signals derived from the teleprinter answer-back code generator; — transmits, after completion of the answer-back code, or in the absence of an answer-back code, two information blocks of three “idle signals P”; — changes the direction of the traffic flow in accordance with § 3.7.11, and reverts to IRS.
3.7.14 End-of-communication procedure
3.7.14.1 If the ISS is required to terminate the established circuit, it sends the “end-of-communication block” containing three “idle signals a”, until the appropriate “control signal 1” or “control signal 2” has been received; however, the number of transmissions of the “end-of-communication block” is limited to four, after which the ISS reverts to the “stand-by” condition. 3.7.14.2 On receipt of the “end-of-communication block” the IRS sends the appropriate control signal indicating correct reception of this block, and reverts to the “stand-by” condition. 3.7.14.3 On receipt of the control signal that confirms the unmutilated reception of the “end-of-communi cation block”, the ISS reverts to the “stand-by” condition. 3.7.14.4 If the IRS is required to terminate the established circuit, it has first to change over to the ISS condition, in accordance with § 3.7.11, before the termination can take place. 52 Rec. 625-1
3 .8 Rephasing procedure
3.8.1 If during the traffic flow, reception of information blocks or control signals is continuously mutilated, both stations change to the “rephase” condition after 32 cycles of continuous repetition. Rephasing is the automatic re-establishment of the previous circuit immediately following interruption of that circuit as a result of continuous repetition (see § 3.7.12). Note. — Some coast stations do not provide for rephasing. Therefore, it should be possible to disable the rephasing procedure. 3.8.2 After changing to the “rephase” condition the master station immediately initiates the rephasing procedure. This procedure is the same as the phasing procedure; however, in the case of a 7-signal call identity, instead of “control signal 4” the rephasing slave station will transmit “control signal 5” after the reception of the appropriate “call signal” transmitted by the rephasing master station. 3.8.3 When “control signal 5” is received by the master station, automatic identification takes place along the same lines as laid down in § 3.6. However, on receipt of the “end-of-identification block”, containing three “signal repetitions”: 3.8.3.1 If, at the time of interruption, the slave station was in the IRS condition, it sends either: — “control signal 1” if the last correctly received block before the interruption occured as an “information block 2”; or — “control signal 2” if the last correctly received block before the interruption occured was an “information block 1”. 3.8.3.2 If, at the time of interruption, the slave station was in the ISS condition, it sends “control signal 3”, to initiate change-over , to the IRS condition. When the change-over is completed, i.e. after correct reception of the block containing three “signal repetitions” by the master station, the master station sends either: — “control signal 1” if the last correptly received block before the interruption occurred was an “information block 2” ; or — “control signal 2” if the last correctly received block before the interruption occurred was an “information block 1”. 3.8.4 On receipt of “control signal 4”, during the rephasing procedure the master station sends one “end-of-communication block” containing three “idle signals a ” after which it continues with the rephasing attempt. 3.8.5 On receipt of each identification block, the slave station compares the received identification signals with the previously stored identity of the master station and: — if the signals are identical, the slave station continues with the procedure by sending the appropriate check-sum signal; — if the signals are not identical, the slave station initiates the “end-of-communication” procedure in accordance with § 3.7.14 and remains in the “rephase” condition. 3.8.6 On receipt of a block containing three “idle signals a”, the slave station sends one “control signal 1” and remains in the “rephase” condition. 3.8.7 In the case of a 4-signal call identity, the rephasing master station: — upon receipt of two consecutive signals “control signal 1 ” or “control signal 2” resumes directly with the transmission of traffic information if the slave station was in the IRS condition, or initiates the change-over procedure in accordance with § 3.7.11.1 if the slave station was in the ISS condition; — upon receipt of two consecutive signals “control signal 3” proceeds directly with the change-over procedure in accordance with § 3.7.11.4 if the slave station was in the ISS condition. 3.8.8 In the case of a 4-signal call identity, the slave station on receipt of the appropriate “call signal” sends: — if, at the time of interruption, the slave station was in the IRS condition, either: — “control signal 1” if it had correctly received “information block 2” before the interruption occurred; or — “control signal 2” if it had correctly received “information block 1” before the interruption occurred; — if, at the time of interruption, the slave station was in the ISS condition, “control signal 3” to initiate change-over to the ISS condition. 3.8.9 If rephasing has not been accomplished within the time-out interval of 32 cycles, both stations revert to the “stand-by” condition and no further rephasing attempts are made. Rec. 625-1 53
3.9 Summary o f service blocks and service information signals 3.9.1 Service blocks Xj - RQ - X2 : “Call block 1” containing the 1st and 2nd identification signals. X3 - X4 - RQ : “Call block 2” for a 4-signal call identity containing the 3rd and 4th identification signals. RQ - X3 - X4 : “Call block 2” for a 7-signal call identity containing the 3rd and 4th identification signals. x 5 - x 6 - X7 : “Call block 3” for a 7-signal call identity containing the 5th, 6th and 7th identification signals. Yi - a - Y2 : “Identification block 1” containing self-identification signals 1 and 2 and request for the 1st check-sum signal. a - Y3 - Y4 : “Identification block 2” containing self-identification signals 3 and 4 and request for the 2nd check-sum signal. Y5-Y 6 -Y7: “Identification block 3” containing self-identification signals 5, 6 and 7 and request for the 3rd check-sum signal. RQ - RQ - RQ : If occurring within the automatic identification procedure, indicates the end of that procedure and requests the appropriate control signal. During the traffic flow, indicates request for repetition of the last control signal or in the change-over procedure response to p-a-p. (3 - a - P : Block to change the direction' of the traffic flow. a - a - a : Block to initiate the end-of-communication procedure. 3.9.2 Service information signals CS1 : Request for “information block 1” or “call signal” has been correctly received during phasing/rephasing (only in the case of a 4-signal call identity). CS2 : Request for “information block 2”, CS3 : IRS requests change of traffic flow direction. CS4 : “Call signal” has been correctly received during phasing. CS5 : “Call signal” has been correctly received during rephasing. RQ : Request for retransmission of the last identification or information block or in the change-over procedure, response to P-a-p.
4. Characteristics, mode B (FEC)
4.1 General The system operates in a synchronous mode, transmitting an uninterrupted stream of signals from a station-sending in the collective B-mode (CBSS) to a number of station receving in the collective B-mode (CBRS), or from a station sending in the selective B-mode (SBSS) to one or more selected stations receiving in the selective B-mode (SBRS). 4.2 The sending station (CBSS and SBSS) The sending station, both in collective and in selective B-mode, sends each signal twice: the first transmission (DX) of a specific signal is followed by the transmission of four other signals, after which the retransmission (RX) of the first signal takes place, allowing for time-diversity reception at 280 ms (4 x 70 ms) time space (see Fig' 2).
DX position • M E S S A G E • • • •
RX position •• • M E S S A G E •
280 ms t
FIGURE 2 - Time-diversity transmission
4.3 The receiving station (CBRS and SBRS) The receiving station, both in collective and selective B-mode, checks both signals (DX and RX), and uses the unmutilated one. When both signals appear as unmutilated but different, then both signals should be considered as mutilated. 54 Rec. 625-1
4.4 Phasing procedure
4.4.1 When no circuit is established, both stations are in the “stand-by” condition and no sending or receiving condition is assigned to either of the stations. 4.4.2 The station required to transmit information becomes the sending station and sends alternately “phasing signal 2” and “phasing signal 1”, whereby “phasing signal 2” is transmitted in the DX position and “phasing signal 1” in the RX position. At least sixteen of these signal pairs should be transmitted. 4.4.3 On receipt of the signal sequence “phasing signal l”-“phasing signal2”, or of the signal sequence “phasing signal 2”-“phasing signal 1”, in which “phasing signal 2” determines the DX position and “phasing signal 1” determines the RX position, and at least two further phasing signals in the appropriate position, the station changes to the CBRS condition and offers continuous stop-polarity to the line output terminal until either the traffic information signal “ (combination No. 27) or “ = ” (combination No. 28) is received.
4.5 Selecting calling procedure (selective B-mode)
4.5.1 After the transmission of the required number of phasing signals, the SBSS sends the “call signal”, which consists of six transmissions of a sequence, each consisting of the identification signals of the station to be selected followed by an “idle signal P”. This transmission takes place using time-diversity in accordance with § 4.2. 4.5.2 The SBSS sends the “call signal” and all further information signals in a 3B/4Y ratio, i.e. inverted with respect to the information signals in Tables I and II and the identification signals in Table Ilia. 4.5.3 The “call signal” contains either four, or seven identification signals as applicable. The identifica tion signals are listed in Table Ilia. The composition of these “call signals” should be in accordance with Recommendation 491. 4.5.4 Following unmutilated reception of one complete signal sequence representing its inverted identifi cation signals, the CBRS changes to the SBRS condition and continues offering stop-polarity to the line output terminal until either the traffic information signal; (combination No. 27) or “==” (combination No. 28) is received. 4.5.5 The station in the SBRS condition accepts the subsequent information signals received with the 3B/4Y ratio, all other stations reverting to the “stand-by” condition.
4.6 Traffic flow
4.6.1 Immediately prior to the transmission of the first traffic signals the sending station transmits the information signals “ (combination No. 27) and “ = ” (combination No. 28), and starts transmitting traffic. 4.6.2 A CBSS sends, during breaks in the information flow, “phasing signals 1” and “phasing signals 2” in the RX and DX positions respectively. At least one sequence of four consecutive phasing signal pairs should occur for every 100 signals sent in the DX position during traffic flow. 4.6.3 A SBSS sends, during breaks in the information flow, “idle signals p”. 4.6.4 On receipt of either the traffic combination signal “ (combination No. 27) or “ = ” (combination No. 28), the receiving station starts printing the received traffic information signals. . Note. — The term “printing” is used in § 4.6.4 and 4.6.5 to denpte the transfer of traffic signals to the output device. 4.6.5 The receiving station checks both signals received in the DX and RX position: — printing an unmutilated DX or RX signal; or — printing a “A” (combination No. 31), or alternatively an “error character” (to be user-defined) if both DX and RX signals are mutilated or appear unmutilated but are different. 4.6.6 A receiving station reverts to the “stand-by” condition if, during a predetermined time, the percentage of mutilated signals received has reached a predetermined value.
4.6.7 End-of-transmission
4.6.7.1 A station sending in the B-mode (CBSS or SBSS) should terminate the transmission by sending at least 2 s of consecutive “idle signals a”, immediately after the last transmitted traffic information signals after which the station reverts to the “stand-by” condition. 4.6.7.2 The receiving station reverts to the “stand-by” condition not less than 210 ms after receipt of at least two consecutive “idle signals a” in the DX position. Rec. 625-1 55
'Station I Station II Master slave
FIGURE 3 - Phasing procedure with automatic identification in the case o f a 7-signal call identity (mode A) 56 Rec. 625-1
S ta tio n I S ta tio n II Master Slave
Identity: 179311383 Identity: I98542S93
FIGURE 4 - Rephasing procedure with automatic identification in the case o f a 7-signal call identity (station II was ISS) Rec. 625-1 57
S to p p olarity
Stop polarity
Stand-by Stand-by
FIGURE 5 - Traffic flow with change-over procedure and' end-of-communication Rec. 625-1
Station I S tation li Master Slave
Call block 2
Call block 3
CS4
Call block 1
ID block 1
CS4
ID block 2
ID block 2
ID block 2 v E
ID block 3
End-of-lD
Block 1
FIGURE 6 - Phasing procedure with automatic identification in the condition of mutilated reception in the case of a 7-signal call identity
* detected error Rec. 625-1 59
Station I Station II Master Slave Transmitter Transmitter
IRS
Printing
Stop polarity
Stop polarity
FIGURE 7 - Traffic flow in the condition of mutilated reception
' ' , * Detected error Rec. 625-1
Station I Station II Master Slave
Transmitter Transmitter
FIGURE 8 - Phasing procedure in the case o f a 4-signal call identity
(*) With somejequipment built in accordance with Recommendation 476 this could be GS2. Rec. 625-1
Station I Station II Master Slave
Transmitter Transmitter
IRS
FIGURE 9 - Phasing procedure in the condition o f mutilated reception in the case o f a 4-signdl call identity .
* Detected error
(*) With some equipment built in accordance with Recommendation 476 this could be CS2. 62 Rec. 625-1
Station I Station II DX I RX CBSS ’ Stand-by
ua,
Error sym bol
FIGURE 10 - Collective B-mode operation
1 : phasing signal 1 2 : phasing signal 2 * : Detected error Rec. 625-1
S ta tio n II Selective call No.: 67890 CBSS Z F S T S ta n d -b y
CBRS
h 2 | h SBSS |1 2 1 zT M H Z| FI h h F| SI h |z S | T| Iz If T| 3l Is 3 1 TT |S Zl f L ^ SBRS :fl * 'If is I zl Is It Z.I FI I f "f I 13 3, S | 13 o |z S| ' Cl. T| |Z IF Tl 1 If IS 31 ~ i |a i S ta n d -b y FIGURE 11 - Selective B-mode operation in the case o f a 4-signal call identity 1 : phasing signal 1 2: phasing signal 2 Over lined symbols (e.g. M) are in the 3B/4Y ratio J 64 Rec. 625-1 Station I Station II FIGURE 12 - Selective B-mode operation in the case o f a 7-signal call identity 1: phasing signal 1 2: phasing signal 2 Overlined symbols (e.g. M) are in the 3B/4Y ratio Rec. 625-1 65 APPENDICES TO ANNEX I APPENDIX I SDL DIAGRAMS (MODE A) 1. General The specification and. description language (SDL) is described in CCITT Recommendations Z.101 to Z.104. The following graphical symbols have been used: State — A “state” is a condition in which the action of a process is suspended awaiting an input. External input Internal input An “input” is an incoming signal which is recognized by a process. External output Internal output An “output” is an action which generates a signal which in turn acts as an input elsewhere. Decision A “decision” is an action which asks a question to which the answer can be obtained at that instant and chooses one of several paths to continue the sequence. Task — A “task” is any action which is neither a decision nor an output. 66 Rec. 625-1 2. Phasing procedure with automatic identification in the case of a 7-signal call identity (calling station) 2.1 The SDL diagrams are given in Appendix II. 2.2 The following supervisory counters are used in the diagrams: Counter Time-out State Sheet n0 128 cycles 02, 03, 04 1 n'i 128 cycles 00 1 n2 32 cycles 05, 06, 07, 08 2, 3 3. Rephasing procedure with automatic identification in the case of a 4-signal call identity (calling station) 3.1 The SDL diagrams are given in Appendix Ifl. 3.2 The following supervisory counters are used in the diagrams: Counter Time-out State Sheet n5 32 cycles 00, 02, 03, 04 s 1 05, 06, 07, 08 2, 3 ni 128 cycles 1 n2 32 cycles 05, 06, 07, 08 2, 3 4. Phasing procedure without automatic identification in the case of a 4-signal call identity (calling station) 4.1 The SDL diagrams are given in Appendix IV. 4.2 The following supervisory counters are used in the diagrams: Counter Time-out State Sheet n0 128 cycles 02, 03 1 nj 128 cycles 00 1 5. Rephasing procedure without automatic identification in the case of a 4-signal call identity (calling station) 5.1 The SDL diagrams are given in Appendix V. 5.2 The following supervisory counters are used in the diagrams: Counter Time-out State Sheet n5 32 cycles 00, 02, 03 1 ni 128 cycles 1 6. Phasing procedure with automatic identification in the case of a 7-signal call identity (called station) 6.1 The SDL diagrams are given in Appendix VI. 6.2 The following supervisory counters are used in the diagrams: Counter Time-out State Sheet n2 32 cycles 05, 06, 07, 08 2, 3 Rec. 625-1 67 7. Rephasing procedure with automatic identification in the case of a 7-signal call identity (called station) 7.1 The SDL diagrams are given in Appendix VII. 7.2 The following supervisory counters are used in the diagrams: Counter Time-out State Sheet n5 32 cycles 00, 01, 02, 03, 04 1 05, 06, 07, 08 2, 3 n2 32 cycles 05, 06, 07, 08 2, 3 8. Phasing procedure without automatic identification in the case of 4-signal call identity (called station) ✓ 8.1 The SDL diagrams are given in Appendix VIII. 9. Rephasing procedure without automatic identification in the case of a 4-signal call identity (called station) 9.1 The SDL diagrams are given in Appendix IX. 9.2 The following supervisory counters are used in the diagrams: Counter Time-out State Sheet n5 32 cycles 00, 01, 03 1 10. Traffic flow in the case of a 4-signal call identity and in the case of a 7-signal call identity (station is in the ISS position) 10.1 The SDL diagrams are given in Appendix X. 10.2 The following supervisory counters are used in the diagrams: Counter Time-out State Sheet n3 32 cycles 09, 10, 13 1, 3 n4 4 cycles 11, 12 2 nt 128 cycles 12 . 2 n5 32 Cycles 11,12,13,14 2,3 11. Traffic flow in the case of a 4-signal call identity and in the case of a 7-signal call identity (station is in the IRS position) 11.1 The SDL diagrams are given in the Appendix XI. 11.2 The following supervisory counters are used in the diagrams: Counter Time-out State Sheet n3 32 cycles 09,10,11 1,2 n5 32 cycles 09,10,11,12 1,2 68 Rec. 625-1 APPENDIX II PHASING PROCEDURE WITH AUTOMATIC IDENTIFICATION IN THE CASE OF A 7-SIGNAL CALL IDENTITY Connector (CALLING STATION) reference Sheet 1 (of 3) 00 M7 Idle Data / [9 digit number input \ I traffic data identification + Stand-by check-sum signals 128 cycles CS4 / CS5 ■ < 1 1 1 Stop Stop Start CB1 -£n, = 128 cycles counter n 0 ? counter n„ ? counter n, 03 Wait 2 ,1 6 Stand-by for CS4 '2-X C S 4 \ CSS ■ < 1 1 Stop Stop N. Start CB2 -jn, =128 cycles counter n 0 ? counter n 0 ? counter n, 04 Wait 2 ,1 6 for CS4 Stand-by 2-X c s 4 \ CS5 / Stop Stop N . Start -fn, = 128 cycles counter n 0 / counter n 0 ' / counter n, 2 ,1 6 Stand-by '2-X t, : call identity the same as the one before and nj > 0? * Detected error or no signal at all Rec. 625-1 69 C o n n e c to r re fe re n c e APPENDIX II Sheet 2 (of 3) 2 3 3 4 3,17 4 5 4.17 5 6 *16 fourth reception of a wrong check-sum signal? *3 same wrong check-sum signal one cycle before? CKn* wrong check-sum signal * Detected error or no signal at all APPENDIX II Sheet 3 (of 3) Connector reference * Detected error or no signal at all Rec. 625-1 71 APPENDIX III PHASING PROCEDURE WITH AUTOMATIC IDENTIFICATION IN THE CASE OF A 7-SIGNAL CALL IDENTITY (CALLING STATION) Connected Sheet 1 (of 3) reference 00- MR7 Idle CB1 CB2 © ; CB3 /o2 Wait for CS5 CS5 CS4 Start CB1 counter = 128 cycles EOC 03 00 Wait Stand-by MR7 for CS5 idle CSS CS4 Start CB2 128 cycles EOC 0 counter 04 r00 MR7 Wait Stand-by for CSS Idle CS5 CS4 Start 1.2 counter 128 cycles EOC 6 , © 00 Stand-by MR7 Idle * Detected error or no signal at all 72 Rec. 625-1 APPENDIX III Sheet 2 (o f 3) t16 : fourth reception of a wrong check-sum signal? t3 : same wrong check-sum signal one cycle before? CKn* : wrong check-sum signal * Detected error or no signal at all Rec. 625-1 73 APPENDIX III Sheet 3 (o f 3) C on nector reference 6 ) 2 ; 3 (2 X ) EOI 08 W ait for CS1 1 1 1 1 1 CS1 R Q < / CS3 C S 2 • < 5: < Stop Stop Stop Stand-by co u n ter n 2 counter n2 cou n ter n2 22 Stop S top 3-X cou n ter n 5 7.11 1-X 1-X * Detected error or no signal at all 74 Rec. 625-1 APPENDIX IV PHASING PROCEDURE WITHOUT AUTOMATIC IDENTIFICATION IN THE CASE C onnector OF A 4-SIGNAL CALL IDENTITY reference (CALLING STATION) ^n, =128 cycli 7,11 -£n, =128 cycle 1.7,11 tj : call identity the same as the one before and nt > 0? t2 : same control signal one cycle before? * Detected error or no signal at all Rec. 625-1 75 APPENDIX V REPHASING PROCEDURE WITHOUT AUTOMATIC IDENTIFICATION IN THE CASE OF A 4-SIGNAL CALL IDENTITY (CALLING STATION) Sheet 1 (of 1) C on nector reference -jnj = 128 cycles -£nj =128 cycles t2 : same control signal one cycle before? * Detected error or no signal at all 76 Rec. 625-1 APPENDIX VI PHASING PROCEDURE WITH AUTOMATIC IDENTIFICATION IN THE CASE OF A 7-SIGNAL CALL IDENTITY (CALLED STATION) Sheet 1 (of 3) * Detected error or no signal at all Rec. 625-1 77 APPENDIX VI Sheet 2 (of 3) C o n n e cto r referen ce © 1 (2 X ) c o u n te r n2 > - - { > 2 =32 cycles © C S 4 0 8 W ait fo r ID 1 ID1 EOC n2 ' R e-set C S l S ta n d -b y c o u n te r n 2 0 © S to p C K 1 co u n te r n2 © 0 9 W ait S ta n d -b y fo r ID 2 ID 2 EOC n2 R e-set C S l S ta n d -b y c o u n te r n2 5 S to p 3 , 4 C K 2 c o u n te r n , 6 10 W ait S ta n d -b y fo r 1D3 ID3 EOC R e-set c o u n te r n 2 C S l S ta n d -b y 5 ,6 ,7 S to p 0 : c o u n te r n2 S ta n d -b y t8 : same ID-block one cycle before? * Detected error or no signal at all 78 Rec. 625-1 APPENDIX VI Sheet 3 (of 3) Connector reference tg : same ID-block one cycle before? * Detected error or no signal at all Rec. 625-1 79 APPENDIX VII REPHASING PROCEDURE WITH AUTOMATIC IDENTIFICATION IN THE CASE OF A 7-SIGNAL CALL IDENTITY (CALLED STATION) Sheet 1 (of 3) C onnector reference * D etected error or no signal at all 80 Rec. 625-1 APPENDIX VII Sheet 2 (o f 3) Connector ' reference 1 ) 1(2X ) CS5 2 / 0 8 Wait for ID1 ID1 ID1" EOC R e-set RQ C S l Stand-by counter n2 0 Stop Stop CK1 counter n2 counter n . ■009 00 Wait SR 7 for ID 2 idle 2-XI ID 2 ID 2* ID1 EOC n2 Re-set 3 counter n2 RQ C S l Stand-by 5 0 Stop 4 CK2 Stop counter n2 counter n2 6 © 1 ^ 3 (10 00 13 Wait SR 7 for ID3 2-XI idle ID3 ID3* ID2 EOC n2 < Stop RQ Stand-by counter n2 C S l 6.7 Stop Stop counter n2 counter n2 00 13 SR7 2-XI idle IDn*: wrong identification signal(s) * Detected error or no signal at all APPENDIX VII Sheet 3 (of 3) Connector reference tu : block 2 was the last received block at the moment the interruption occurred? * Detected error or no signal at all 82 Rec. 625-1 APPENDIX VIII PHASING PROCEDURE WITHOUT AUTOMATIC IDENTIFICATION IN THE CASE OF A 4-SIGNAL CALL IDENTITY (CALLED STATION) Sheet 1 (of 1) '• * Detected error or no signal at all Rec. 625-1 83 APPENDIX IX REPHASING PROCEDURE WITHOUT AUTOMATIC IDENTIFICATION IN THE CASE OF A 4-SIGNAL CALL IDENTITY (CALLED STATION) Sheet 1 (of 1) C o n n e c to r r e fe r e n c e tn : block 2 was the last received block at the moment the interruption occurred? * Detected error or no signal at all 84 Rec. 625-1 APPENDIX X TRAFFIC FLOW IN THE CASE OF A 4-SIGNAL CALL IDENTITY AND IN THE CASE OF A 7-SIGNAL CALL IDENTITY (STATION IS IN THE ISS POSITION) Sheet 1 (of 3) C o n n e c to r referen ce 1-IV(2X); 7 1-V(2X); ( 7 3-II; 3-III n3 = 32 cycles 8 J Read next 3 signals from 26 | traffic data buffer 9 10,14 11 CS3 &3 9,20 RQ RQ RQ ISS 10,23 J" Read next 3 signals 1 from traffic data buffer 12 13 ' 17 CS3 n3 12,20 RQ RQ RQ> ISS 8,13,23 ts : data block contains message “end-of-communication”? ISS: notice: station is ISS at the moment the interruption occurred * Detected error or no signal at all Rec. 625-1 85 APPENDIX X C onnector reference Sheet 2 (of 3) 1 4 15 15 25 16 17 19 19 25 * Detected error or no signal at all 86 Rec. 625-1 APPENDIX X Sheet 3 (of 3) C onnector reference 22 20 21 20 23 21 25 18 t6 : station is master station? t7 : station working in the case of a 4-position call identity? ISS : notice: station is ISS at the moment the interruption occurred COl: if ISS is: - master then “RQ RQ RQ”, - slave then “RQ” * Detected error or no signal at all Rec. 625-1 87 APPENDIX XI TRAFFIC FLOW IN THE CASE OF A 4-SIGNAL CALL IDENTITY AND IN THE CASE OF A 7-SIGNAL CALL IDENTITY (STATION IS IN THE IRS POSITION) tu : block 2 was the last received block? IRS1: notice: station is IRS at the moment the interruption occurred, last received block 1 t13 : the emitting control signal is CS3? IRS2: notice: station is IRS at the moment the t14 : block 1 with or without the previous block 2 interruption occurred, last received block 2 contains the sequence “+ ?”?■ * Detected error or no signal at all t15 : block 2 with or without the previous block 1 contains the sequence “+ ?”? 88 Rec. 625-1 APPENDIX XI Sheet 2 (of 2) C on n ector referen ce t6 : station is master station? t7 : station working in the case of a 4-signal call identity? C 0 2 : if IRS is: — master then “RQ”; - slave then “RQ RQ RQ” * Detected error or no. signal at all Rec. 625-1 89 APPENDIX XII PHASING PROCEDURE WITH AUTOMATIC IDENTIFICATION IN THE CASE OF A 7-SIGNAL CALL IDENTITY (CALLING STATION) AND TRAFFIC FLOW IF THE STATION IS IN THE ISS POSITION (STATE OVERVIEW DIAGRAM) Sheet 1 (of 8) Stand-by Rephasing num ber State description Sheet reference Counters running 00 M7 idle MI n i 02 Wait for CS4 l-II n 0 03 Wait for CS4 l-II no Supervisory counters 04 Wait for CS4 l-II no 05 Wait for CK1 2-II n2 na = 128 cycles 06 . Wait for CK2 2-11 • n2 n, = 128 cycles 07 Wait for CK3 2-11 n2 n2 = 32 cycles 08 Wait for CSl n2 3-II n3 = 32 cycles 09 Wait for CS2 1-X n 3 n4 = 4 cycles 10 Wait for C Sl 1-X n 3 - 11 Wait for CS2 2-X n4 12 Wait for CSl 2-X n ,.,n 4 13 Wait for change-over 3-X n3 90 Rec. 625-1 APPENDIX XII REPHASING PROCEDURE WITH AUTOMATIC IDENTIFICATION IN THE CASE OF A 7-SIGNAL CALL IDENTITY (CALLING STATION) AND TRAFFIC FLOW IF THE STATION IS IN THE ISS POSITION (STATE OVERVIEW DIAGRAM) Sheet 2 (o f 8) Stand-by Rephasing Rephasing State number State description Sheet reference Counters running ‘ 00 MR7 idle l-III ris 02 Wait for CSS l-III n5 03 Wait for CS5 l-III n, -o'. 04 Wait for CSS l-III ns Supervisory counters 05 Wait for CK1 2-III n2, ns n, = 128 cycles 06 Wait for CK2 2-III n2, n5 . n2 = 32 cycles 07 Wait for CK3 2-III n2,ns n3 = 32 cycles 08 Wait for CSl ' 3-III n2>ns n4 = 4 cycles 09 Wait for CS2 1-X n3,ns n s = 32 cycles 10 Wait for CSl 1-X n3,ns 11 Wait for CS2 2-X n4,n, 12 Wait for CSl 2-X nj,n4,.ns 13 Wait for change-over 3-X n3>n5 Rec. 625-1 91 APPENDIX XII PHASING PROCEDURE WITHOUT AUTOMATIC IDENTIFICATION IN THE CASE OF A 4-SIGNAL CALL IDENTITY (CALLING STATION) AND TRAFFIC FLOW IF THE STATION IS IN THE ISS POSITION (STATE OVERVIEW DIAGRAM) Sheet 3 (of 8) Stand-by State number State description Sheet reference Counters running M4 idle 1-IV 00 *1 Supervisory counters 02 Wait for CSl 1-IV no 03 Wait for CSl 1-IV n o n0 = 128 cycles 09 Wait for CS2 1-X n3 nj = 128 cycles 10 Wait for CSl 1-X n3 n3 = 32 cycles 11 Wait for CS2 2-X n4 = 4 cycles 12 Wait for CSl 2-X «i. n4 13 Wait for change-over 3-X n . 92 Rec. 625-1 APPENDIX XII REPHASING PROCEDURE WITHOUT AUTOMATIC IDENTIFICATION IN THE CASE OF A 4-SIGNAL CALL IDENTITY (CALLING STATION) AND TRAFFIC FLOW IF THE STATION IS IN THE ISS POSITION (STATE OVERVIEW DIAGRAM) Sheet 4 (of 8) Stand-by Rephasing ■ num ber State description S h eet reference Counters running 00 MR4 idle 1-V n5 Supervisory counters 02 Wait for CSl 1-V ns 03 Wait for CSl 1-V n 5 nj = 128 cycles 09 Wait for CS2 1-X n! n3 = 32 cycles 10 Wait for CSl 1-X n 3 n4 = 4 cycles 11 Wait for CS2 2-X n4 n, = 32 cycles 12 ' Wait for CSl 2-X n , , n 4 13 - Wait for change-over 3-X n 3 Rec. 625-1 93 APPENDIX XII PHASING PROCEDURE WITH AUTOMATIC IDENTIFICATION IN THE CASE OF A 7-SIGNAL CALL IDENTITY (CALLED STATION) AND TRAFFIC FLOW IF THE STATION IS IN THE IRS POSITION (STATE OVERVIEW DIAGRAM) Sheet 5 (of 8) ' Stand-by State number. State description Sheet reference Counters running 00 S7 idle 1-VI 01 Wait for CB2 1-VI 02 Wait for CB3 1-VI 03 Wait for CB3 1-VI Supervisory counters 04 Wait for CB1 1-VI = 32 cycles 08 Wait for ID 1 2-VI = 32 cycles 09 Wait for ID 2 2-VI 10 Wait for ID3 2-VI 11 Wait for EOI 3-VI 12 Wait for block 1 1-XI 13 Wait for block 2 1-Xl 14 _ Wait for /3a/3 2-XI 94 Rec. 625-1 APPENDIX XII REPHASING PROCEDURE WITH AUTOMATIC IDENTIFICATION IN THE CASE OF A 7-SIGNAL CALL IDENTITY (CALLED STATION)'AND TRAFFIC FLOW IF THE STATION IS IN THE IRS POSITION (STATE OVERVIEW DIAGRAM) Sheet 6 (of 8) Stand-by Rephasing State number State description Sheet reference Counters running 00 SR7 idle 1-VII n 5 01 Wait for CB2 1-VII n s 02 Wait for CB3 1-VII n 5 Supervisory counters 03 Wait for CB3 1-VII n5 04 Wait for CB1 1-VII n5 n3 = 32 cycles 08 Wait for ID1 2-VII n2 » ns n3 = 32 cycles 09 Wait for ID 2 2-VII : , n 5 n5 = 32 cycles 10 Wait for ID 3 2-VII n2 > n5 11 Wait for EOI 3 -VII n2, n s 12 Wait for block 1 1-XI n3 > n 5 13 Wait for block 2 1-XI n3, n 5 14 Wait for /3a/3 2-XI n 3, n 5 Rec. 625-1 95 APPENDIX XII PHASING PROCEDURE WITHOUT AUTOMATIC IDENTIFICATION IN THE CASE OF A 4-SIGNAL CALL IDENTITY (CALLED STATION) AND TRAFFIC FLOW IF THE STATION IS IN THE IRS POSITION (STATE OVERVIEW DIAGRAM) - ' Sheet 7 (o f 8) Stand-by State number State description Sheet reference Counters running 00 S4 idle 1-VIIi Supervisory counters 01 Wait for CB2 1-VIII 03 Wait for CB1 1-VIII n3 = 32 cycles 12 Wait for block 1 1-XI 13 Wait for block 2 1-XI 14 Wait for (3a(3 2-XI 96 Rec. 625-1 APPENDIX XII REPHASING PROCEDURE WITHOUT AUTOMATIC IDENTIFICATION IN THE CASE OF A 4-SIGNAL CALL IDENTITY (CALLED STATION) AND TRAFFIC FLOW IF THE STATION IS IN THE IRS POSITION " (STATE OVERVIEW DIAGRAM) Sheet 8 (o f 8) Stand-by Rephasing State number State description Sheet reference Counters running 00 SR4 idle ' l-ix n s Supervisory counters 01 Wait for CB2 1-IX ns 03 Wait for CB1 1-IX ' n, n* _ 32 cycles 12 Wait for block 1 1-XI n3, ns n3 = 32 cycles 13 Wait for block 2 1-XI n3,n5 ns = 32 cycles 14 Wait for /3a0 2-XI n3,n5 Rec. 476-4 97 RECOMMENDATION 476-4* DIRECT-PRINTING TELEGRAPH EQUIPMENT IN THE MARITIME MOBILE SERVICE** (Question 5/8) (1970-1974-1978-1982-1986) The CCIR, CONSIDERING (a) that there is a requirement to interconnect mobile stations, or mobile stations and coast stations, equipped with start-stop apparatus employing the International Telegraph Alphabet No. 2, by means of radiotelegraph circuits; (b) that direct-printing telegraphy communications in the maritime mobile service can be listed in the following categories: b.a telegraph service between a ship and a coast station; b.b telegraph service between a ship and an extended station (ship’s owner) via a coast station; b.c telex service between a ship and a subscriber of the (international) telex network; b.d broadcast telegraph service from a coast station to one or more ships; b.e telegraph service between two ships or between one ship and a number of other ships; (c) that those categories are different in nature and that consequently different degrees of transmission quality may be required; (d) that the categories given in b.a, b.b and b.c above may require a higher transmission quality than categories b.d and b.e for the reason that data could be handled through the services in the categories b.a, b.b and b.c, while the messages passed through the service of category b.d, and via the broadcast service of category b.e are normally plain language, allowing a lower transmission quality than that required for coded information; (e) that the service in category b.d and the broadcast service in category b.e cannot take advantage of an ARQ method, as there is in principle no return path; . (f) that for these categories of service which by their nature do not allow the use of ARQ, another mode, i.e. the forward error-correcting (FEC) mode should be used; (g) that the period for synchronization and phasing should be as short as possible and should not exceed 5 seconds; . (h) that most of the ship stations do not readily permit simultaneous use of the radio transmitter and radio receiver; (j) that the equipment on board ships should be neither unduly complex nor expensive; (k) that provision is made in Appendix 38 of the Radio Regulations for direct-printing telegraph operation, UNANIMOUSLY RECOMMENDS 1. that when an error-detecting and correcting system is used for direct-printing telegraphy in the maritime mobile service, a 7-unit ARQ system or a 7-unit forward acting, error-correcting and indicating time-diversity system, using the same code, should be employed; 2. that equipment designed in accordance with § 1 should meet the characteristics laid down in Annex I. ANNEX I 1. General (Mode A, ARQ and Mode B, FEC) 1.1 , The system is a single-channel synchronous system using the 7-unit error-detecting code as listed in § 2 of this Annex. * The Director, CCIR is requested to bring this Recommendation to the attention of the CCITT. ** This Recommendation is retained in order to provide information concerning existing equipment, but will. probably be deleted at a later date. New equipment should conform to Recommendation 625 which provides for the exchange of identification signals, for the use of 9 digit maritime mobile service identification signals and for compatibility with existing equipment built in accordance with this Recommendation. 98 Rec. 476-4 1.2 The modulation rate on the radio link is 100 bauds. The equipment clocks controlling the modulation rate should have an accuracy of better than 30 parts in 106. Note. — Some existing equipments may not conform to this requirement. 1.3 The terminal input must be able to accept the 5-unit start-stop CCITT International Telegraph Alphabet No. 2 at a modulation rate of 50 bauds. > 1.4 The frequency shift on the radio link is 170 Hz. When frequency shift is effected by applying audio signals to the input of a transmitter, the centre frequency of the audio spectrum offered to the transmitter should be 1700 Hz. Note. — A number of equipments are presently in service, using a centre frequency of 1500 Hz. These may require special measures to achieve compatibility. ' v 1.5 The radio frequency tolerance of the transmitter and the receiver should be in accordance with Appendix 38 of the Radio Regulations. It is desirable that the receiver employs the minimum practicable bandwidth (see also Report 585). Note. — The receiver bandwidth should preferably be between 270 and 340 Hz. 2. Table of conversion 2.1 Traffic information signals TABLE I International C om bi Em itted Letter- Figure- Telegraph nation 7-unit case case Alphabet No. 2 N o. signal (') C ode 1 1 A ZZAAA BBBYYYB 2 B ? ZAAZZ YBYYBBB 3 C AZZZA BYBBBYY 4 D B ( 3) ZAAZA BBYYBYB 5 E 3 ZAAAA YBBYBYB 6 F (2) ZAZZA B B Y B B Y Y , 7 G ( 2) AZAZZ BYBYBBY 8 H (2) AAZAZ BYYBYBB 9 I 8 AZZAA BYBBYYB 10 J Audible signal ZZAZA BBBYBYY 11 K ( ZZZZA YBBBBYY 12 L ) AZAAZ BYBYYBB 13 M AAZZZ BYYBBBY 14 N AAZZA BYYBBYB 15 O 9 AAAZZ BYYYBBB 16 P 0 AZZAZ BYBBYBY 17 Q 1 ZZZAZ YBBBYBY 18 R 4 AZAZA BYBYBYB 19 S 9 ZAZAA BBYBYYB 20 T 5 AAAAZ YYBYBBB 21 U 7 ZZZAA YBBBYYB 22 V = AZZZZ YYBBBBY 23 w 2 ZZAAZ BBBYYBY 24 X / ZAZZZ YBYBBBY 25 Y 6 ZAZAZ BBYBYBY 26 Z + ZAAAZ BBYYYBB 27 - (Carriage return) AAAZA YYYBBBB 28 = (Line feed) AZAAA YYBBYBB 29 l (Letter shift) ZZZZZ YBYBBYB 30 f (Figure shift) ZZAZZ YBBYBBY 31 Snar.p. AAZAA YYBBBYB 32 Unperforated tape AAAAA YBYBYBB (‘) B represents the higher emitted frequency and Y the lower. (2) At present unassigned (see CCITT Rec. F.l C8). Reception of these signals, however, should not initiate a request for repetition. (3) The pictorial representation shown is a schematic of (j 2.2 Service information signals TABLE II Mode A (ARQ) Emitted signal Mode B (FEC) Control signal 1 (CSl) BYBYYBB Control signal 2 (CS2) YBYBYBB Control signal 3 (CS3) BYYBBYB Idle signal p BBYYBBY Idle signal a BBBBYYY Phasing signal 1 Signal repetition YBBYYBB Phasing signal 2 3. Characteristics 3.1 Mode A (ARQ) (see Figs. 1 and 2) ' A synchronous system, transmitting blocks of three characters from an information sending station (ISS) towards an information receiving station (IRS), which stations can, controlled by the control signal 3 (see § 2.2), interchange their functions. 3.1.1 Master and slave arrangements 3.1.1.1 The station that initiates the establishment of the circuit (the calling station) becomes the “master” station, and the station that has been called will be the “slave” station; this situation remains unchanged during the entire time in which the established circuit is maintained, regardless of which station, at any given time, is the Information Sending Station (ISS) or Information Receiving Station (IRS); 3.1.1.2 the clock in the master station controls the entire circuit (see circuit timing diagram, Fig. 1); 3.1.1.3 the basic timing cycle is 450 ms, and for each station consists of a transmission period followed by a transmission pause during which reception is effected; 3.1.1.4 the master station transmitting time distributor is controlled by the clock in the master station; 3.1.1.5 the slave station receiving time distributor is controlled by the received signal; 3.1.1.6 the slave station transmitting time distributor is phase-locked to the slave station receiving time distributor; i.e. the time interval between the end of the received signal and the start of the transmitted signal (tE in Fig. 1) is constant; 3.1.1.7 the master station receiving time distributor is controlled by the received signal. 3.1.2 The Information Sending Station (ISS) 3.1.2.1 Groups the information to be transmitted into blocks of three characters (3x7 signal elements), including, if necessary, “idle signals P” to complete or to fill blocks when no traffic information is available; 3.1.2.2 emits a “block” in 210 ms after which a transmission pause of 240 ms becomes effective, retaining the emitted block in memory until the appropriate control signal confirming correct reception by the Information Receiving Station (IRS) has been received; 3.1.2.3 numbers successive blocks alternately “Block 1” and “Block 2” by means of a local numbering device. The first block should be numbered “Block 1” or “Block 2” dependent on whether the received control signal (see § 3.1.4.5) is a control signal 1 or a control signal 2. The numbering of successive blocks is interrupted at the reception of : — a request for repetition; or — a mutilated signal; or — a control signal 3 (see § 2.2); 3.1.2.4 emits the information of Block 1 on receipt of control signal 1 (see § 2.2); 3.1.2.5 emits the information of Block 2 on receipt of control signal 2 (see § 2.2); 3.1.2.6 emits a block of three “signal repetitions” on receipt of a mutilated signal (see § 2.2). 100 Rec. 476-4 Selective call No. 32610 transmitted as Station I S tation II (see Rec. 491 § 2 ,3) 1 Q(RQ)C | [xt(RQ)1 Transmitter Receiver Transmitter Receiver M aster S 3.1.4.1 Standby Standby- station s 3.1.3.1 j 53.1.4.2 ( Call block 1 Master station Call block 2 j 53.1.4.4 I IRS M aster statio n ISS Information block Slave Slave statio n IRS I Sj- rnntrol signal. "I? Call block 1 r q ______c 5 3.1.4.51 Information block CS1 ISS I C S l , Call block 2 £ ------RQ - p - * - Slave station ISS o — • R L T Control sianqj 70ms M aster statio n IRS B lock 1 l Information block ______M -- : - Control sipnal m s 210 B lock 2 Basic timing cycle B lock 1 B lock 2 jj ______fl g 3.1.6.1 Block “over” a 153.1.6.2 I ISS 53.1.6.2 RQ 5 3.1.6 .1 j IRS ! r q Change of diredt ion ^ RQ______CSl ,k B lock 1 S B lock 2 i __ ? Block 1 B _ 5 3.1.6.21 ot Block “over” ISS i B______153.1.6.1 RQ i IRS FIGURE 1 - A-Mode operation a) Start of communication Block 1 r .______s b) Change of the direction of the traffic flow c) End of communication CS: Control signal of communication g ------of ISS: Information sending station IRS: Information receiving station Standby Standby RQ: Signal repetition information signal t: Figure shift tp: (One way) propagation time *The transmission of these signals may be omitted. tE: (Fixed) equipment delay Rec. 476-4 101 S tatio n I Station II M aster S lave Transmitter Receiver Receiver Transmitter * Detected error Symbol. FIGURE 2 - Mode A under error receiving conditions 3.1.3 The Information Receiving Station (IRS) 3i 1.3.1 Numbers the received blocks of three characters alternately “Block 1” and “Block 2” by a local numbering device, the numbering being interrupted at the reception of: — a block in which one or more characters are mutilated; or — a block containing at least one “signal repetition”; (3.1.2.6) 3.1.3.2 after the reception of each block, emits one of the control signals of 70 ms duration after which a transmission pause of 380 ms becomes effective; 3.1.3.3 emits the control signal 1 at the reception of: — an unmutilated “Block 2”, or — a mutilated “Block 1”, or — Block 1” containing at least one “signal repetition”; 3.1.3.4 emits the control signal 2 at reception of: — an unmutilated “Block 1”, or — a mutilated “Block 2”, or — a “Block 2” containing at least one “signal repetition”. r u .i.t . *) X ^ _ | n5 z 102 Rec. 476-4 3 .1 .4 Phasing 3.1.4.1 When no circuit is established, both stations are in the “stand-by” position. In this stand-by position no ISS or IRS and no master or slave position is assigned to either of the stations; 3.1.4.2 the station desiring to establish the circuit emits the “call” signal. This “call” signal is formed by two blocks of three signals; 3.1.4.3 the call signal contains: — in the first block: “signal repetition” in the second character place and any combination of information signals * in the first and third character place, — in the second block: “signal repetition” in the third character place preceded by any combination of the 32 information signals’" in the first and second character place; 3.1.4.4 on receipt of the appropriate call signal the called station changes from stand-by to the IRS position and emits the control signal 1 or the control signal 2; 3.1.4.5 on receipt of two consecutive identical control signals, the calling station changes into ISS and operates in accordance with § 3.1.2.4 and 3.1.2.5. 3.1.5 Rephasing** 3.1.5.1 When reception of information blocks or of control signals is continuously mutilated, the system reverts to the “stand-by” position after a predetermined time (a preferable predetermined time would be the duration of 32 cycles of 450 ms), to be decided by the user, of continuous repetition; the station that is master station at the time of interruption immediately initiates rephasing along the same lines as laid down in § 3.1.4; 3.1.5.2 if, at the time of interruption, the slave station was in the IRS position, the control signal to be returned after phasing should be the same as that last sent before the interruption to avoid the loss of an information block upon resumption of the communication. (Some existing equipments may not conform to this requirement); 3.1.5.3 however, if, at the time of interruption, the slave station was in the ISS position, it .emits, after having received the appropriate call blocks, either: — the control signal 3; or — the control signal 1 or 2 in conformity with § 3.1.4.4, after which control signal 3 is emitted to initiate changeover to the ISS position; 3.1.5.4 if rephasing has not been accomplished within the time-out interval of § 3.1.9.1, the system reverts to the stand-by position and no further rephasing attempts are made. 3.1.6 Change-over 3.1.6.1 The Information Sending Station (ISS) — Emits, to initiate a change in the direction of the traffic flow, the information signal sequence “Figure shift” — “Plus” (“figure case of Z”) — “Question Mark” (“figure case of B ”)*** followed, if necessary, by one or more “Idle Signals P” to complete a block; — emits, on receipt of a control signal 3, a block containing the signals “Idle Signal P” — “Idle Signal a ” — “Idle Signal p”; — changes subsequently to IRS after the reception of a “signal repetition”. 3.1.6.2 The Information Receiving Station (IRS) — Emits the control signal 3: (a) when the station wishes to change over to ISS, (b)on receipt of a block in which the signal information sequence “Figure shift” — “Plus” — (figure-case of Z) — “Question Mark” (figure-case of B) terminates *** or upon receipt of the following block. In the latter case, the IRS shall ignore whether or not one or more characters in the last block are mutilated: — changes subsequently to ISS after reception of a block containing the signal sequence “Idle signal P” — “Idle signal a” “Idle signal P”; — emits one “signal repetition” as a master station, or a block of three “signal repetitions” as a slave station, after being changed into ISS; * The composition of these signals and their assignment to individual ships require international agreement (see Recommen dation 491). ** Some coast stations do not provide rephasing (see also Recommendation 492). *** In the Telex network, the signal sequence combination No. 26 — combination No. 2, sent whilst the teleprinters are in the figure case condition, is used to initiate a reverasl of the flow of information. The IRS is, therefore, required to keep track of whether the traffic information flow is in the letter-case or figure-case mode to ensure proper end-to-end operation of the system . Rec. 476-4 103 3.1.7 Output to line 3.1.7.1 the signal offered to the line output terminal is a 5-unit start-stop signal at a modulation rate of 50 bauds. 3.1.8 Answerback 3.1.8.1 The WRU (Who are you?) sequence, which consists of combination Nos. 30 and 4 in the International Telegraph Alphabet No. 2, is used to request terminal identification! 3.1.8.2 The Information Receiver Station (IRS), on receipt of a block containing the WRU sequence, which will actuate the the teleprinter answerback code generator: — changes the direction of traffic flow in accordance with § 3.1.6.2; — transmits the signal information characters derived from the teleprinter answerback code generator; — after transmission of 2 blocks of “Idle signals fT (after completion of the answerback code, or in the absence of an answerback code), changes the direction of traffic flow in accordance with § 3.1.6.1. Note. — Some existing equipments may not conform to this requirement. 3.1.9 End o f communication 3.1.9.1 When reception of information blocks or of control signals is continuously mutilated, the system reverts to the “stand-by” position after a predetermined time of continuous repetition, which causes the termination of the established circuit, (a preferable predetermined time would be the duration of 64 cycles of 450 ms); 3.1.9.2 the station that wishes to terminate the established circuit transmits an “end of communication signal”; 3.1.9.3 the “end of communication signal” consists of a block containing three “Idle Signal a”: 3.1.9.4 the “end of communication signal” is transmitted by the ISS; 3.1.9.5 if an IRS wishes to terminate the established circuit it has to change over to ISS in accordance with § 3.1.6.2; 3.1.9.6 ihe IRS that receives an “end of communication signal” emits the appropriate control signal and reverts to the “stand-by” position; 3.1.9.7 on receipt of a control signal that confirms the unmutilated reception of the “end of communica tion signal”, the ISS reverts to the “stand-by” position; 3.1.9.8 when after a predetermined number of transmissions* of the “end of communication signal” no control signal has been received confirming the unmutilated reception of the “end of communication signal”, the ISS reverts to the stand-by position and the IRS times out in accordance with § 3.1.9.1. 3.2 Mode B, forward error correction (FEC) (see Figs. 3 and 4) A synchronous system, transmitting an uninterrupted stream of characters from a station sending in the collective B-mode (CBSS) to a number of stations .receiving in the collective B-mode (CBRS), or from a station sending in the selective B-mode (SBSS) to one selected station receiving in the selective B-mode (SBRS). 3.2.1 The station sending in the collective or in the selective B-mode (CBSS or SBSS) 3.2.1.1 Emits each character twice: the first transmission (DX) of a specific character is followed by the transmission of four other characters, after which the retransmission (RX) of the first character takes place, allowing for time-diversity reception at 280 ms time space; 3.2.1.2 emits as a preamble to messages or to the call sign, alternately the phasing signal 1 (see § 2.2) and the phasing signal 2 (see § 2.2) whereby phasing signal 1 is transmitted in the RX, and phasing signal 2 in the DX position. At least four of these signal pairs (phasing signal 1 and phasing signal 2) should be transmitted. 3.2.2 The station sending in the collective B-mode (CBSS). 3.2.2.1 Emits during the breaks between two messages in the same transmission the phasing signals 1 and the phasing signals 2 in the RX and the DX position, respectively. 3.2.3 The station sending in the selective B-mode (SBSS) 3.2.3.1 Emits after the transmission of the required number of phasing signals (see § 3.2.1.2) the call sign of the station to be selected. This call sigii is a sequence of four characters that represents the number code of the called station. This transmission takes place in the time diversity mode according to § 3.2.1.1; A preferable predetermined number would be four transmissions of the “end of communication signal”. Rec. 476-4 3.2.3.2 emits the call sign and all further signals in a 3B/4Y ratio, i.e. inverted with respect to the signals in Table I of § 2 in the column “emitted 7-unit signal”. Consequently, all signals, i.e. both traffic information signals and service information signals, following the phasing signals are transmitted in the 3B/4Y ratio; 3.2.3.3 emits the service information signal “Idle signal |3” during the idle time between the messages consisting of traffic information signals. 3.2.4 The station(s) receiving in the collective or in the selective B-mode (CBRS or SBRS) 3.2.4.1 Checks both characters (DX and RX), printing an unmutilated DX or RX character, or printing an error symbol or space, if both are mutilated. 3.2.5 Phasing 3.2.5.1 When no reception takes place, the system is in the “stand-by” position as laid down in § 3.1.4.1; 3.2.5.2 on receipt of the sequence “phasing signal 1” — “phasing signal 2”, or of the sequence “phasing signal 2” — “phasing signal 1”, in which phasing signal 2 determines the DX and phasing signal! determines the RX position, and at least one further phasing signal in the appropriate position, the system changes from “stand-by” to the CBRS position; 3.2.5.3 when started as CBRS the system changes to the SBRS (selectively called receiving station) position on receipt of the inverted characters representing its selective call number; 3.2.5.4 having been changed into the CBRS or into the SBRS position the system offers continuous stop-polarity to the line output terminal until either the signal “carriage return” or “line feed” is received; 3.2.5.5 when started as SBRS, the decoder re-inverts all the following signals received to the 3Y/4B ratio, so that these signals are offered to the SBRS in the correct ratio, but they remain inverted for all other stations; 3.2.5.6 both the CBRS and the SBRS revert to the stand-by position if, during a predetermined time, the percentage of mutilated signals received has reached a predetermined value. 3.2.6 Output to line 3.2.6.1 The signal offered to the line output terminal is a 5-unit start-stop CCITT International Telegraph Alphabet No. 2 signal at a modulation rate of 50 bauds. 3.2.7 End o f emission 3.2.7.1 The station sending in the B-mode (CBSS or SBSS) that wishes to terminate the emission transmits the “end of emission signal”; \ 3.2.7.2 the “end of emission signal” consists of three consecutive “idle signals a ” (see § 2.2) transmitted in the DX position only, immediately after the last transmitted traffic information signal in the DX position, after which the station terminates its emission and reverts to the “stand-by” position; "end of emission signal” M. E.S.S.A .G.E .a.a a DX-position RX-position revert to “stand-by” 3.2.7.3 the CBRS or the SBRS reverts to the “stand-by” position not less than 210 ms after receipt of at least two consecutive “idle signals a” in the DX position. Rec. 476-4 Station I Station II Station I Station II F IG U R E 3 - B-mode operation Collectively Selectively 1: Phasing signaM CBSS: B-mode - Sending collectively 2: Phasing signal 2 CBRS: B-mode - Receiving collectively <: Carriage return (CR) SBSS: B-mode - Sending selectively = : Line feed (LF) SBRS: B-mode - Receiving selectively * Detected error symbol Overlined symbols (e.g. M) are transmitted in the 3B/4Y ratio 106 Rec. 476-4 FIGURE 4 - Flow chart showing processes in B-Mode operation Rec. 490 107 RECOMMENDATION 490 THE INTRODUCTION OF DIRECT-PRINTING TELEGRAPH EQUIPMENT IN THE MARITIME MOBILE SERVICE Equivalence of terms (Question 5/8) (1974) The CCIR, CONSIDERING (a) that the use of direct-printing telegraphy by ship and coast stations is rapidly expanding; (b) that there is a need for standardizing the designation of the higher and lower FIB frequencies to ensure compatible world-wide operation when using the direct-printing telegraphy system; 1 V UNANIMOUSLY RECOMMENDS that the equivalence of terms as shown in the following table shall be adhered to (this Recommendation is in accordance with CCITT Recommendations U.l and V.I.): TABLE! Circuits using teleprinter or punched tape equipment Frequency o f em ission Em itted International Telegraph Alphabet No. 2 Telex 7-unit signal Higher Free line Space Start N o perforation AO BO frequency con dition I Lower Idle circuit M ark Stop Perforation z o YO frequency con dition I1) on a wire circuit. (2) on a radio channel. 108 Rec. 491-1 RECOMMENDATION 491-1 TRANSLATION BETWEEN AN IDENTITY NUMBER AND IDENTITIES FOR DIRECT-PRINTING TELEGRAPHY IN THE MARITIME MOBILE SERVICE (Question 5/8) (1974-1986) The CCIR, CONSIDERING (a) that, according to Article 25 of the Radio Regulations, a station shall be identified either by a call sign or by other recognized means of identification, such as a ship station selective call number or signal, or coast station selective call number or signal; (b) that the call signals described in Recommendations 476 and 625 effectively provide for selective-calling numbers for use with direct-printing telegraph equipment; (c) that this signal is unique for each station and may therefore be used as its identification; (d) that the use of this signal makes unattended operation of direct-printing equipment possible; (e) that it would be convenient if the numbers assigned in accordance with Article 25, Sections V and VI of the Radio Regulations were used in the phasing procedure; (f) that there is a need for a conversion scheme from numerical identification to the identification signals used in the call signal, UNANIMOUSLY RECOMMENDS 1. that, in direct-printing telegraphy systems, the call signals described in Recommendations 476 and 625 may be used as identification of a radio station; 2. that the conversion from the numerical identification to the identification signals used in the call signal should be performed according to the Tables in Annexes I and II. Rec. 491-1 109 ANNEX I TRANSLATION BETWEEN A 5- OR 4-DIGIT IDENTITY NUMBER AND A 4-SIGNAL IDENTITY To translate a number, proceed as follows: For a 5-digit number let the first digit determine which vertical column in Table I to use. Translate the last four digits to four alphabetic characters as indicated for each digit in the column selected in accordance with the table of conversion as given in Table I. For a 4-digit number Table II should be used. Examples: The 5-digit number 32610 is transmitted as: Q (RQ) c X T (RQ) The 4-digit number 1234 is transmitted as: X (RQ) Q K M (RQ) T able I T able II 5-digit numbers 4-digit numbers 1st digit 0 1 2 3 4 5 6 7 8 9 0 T V . V V T T T V V V 0 V 1 B X X X B B B X X X 1 X 2 U Q Q Q U U U Q Q Q 2 Q 3 E K K K E E E K K K 3 K 2nd digit 4 O M M M O O O M M M 1st digit 4 M 5 I P P P I I I P P P 5 P 6 R C C C R R R C C C 6 C 7 Z Y Y Y Z Z Z Y Y Y 7 Y 8 D F F F D D D F F F 8 F 9 A S S S A A A S S S 9 S 0 V T V V T V V T T V 0 V 1 X B X X B X X B B X 1 X 2 Q U Q Q U Q Q U U Q 2 Q 3 K E K K E K K E E K 3 K 3rd digit 4 M O M M 0 M M O O M 2nd digit 4 M 5 P I P P I P P I I P 5 P 6 C R C C R C C R R C 6 C 7 Y Z Y Y Z Y Y Z Z Y 7 Y 8 F D F F D F F D D F 8 F 9 S A S S A s S A A S 9 S 0 V V T V -v T V T V T 0 V 1 X X B X X B X B X B 1 X 2 Q Q U Q Q U Q U Q U 2 Q 3 K K E K K E K E K E 3 K 4th digit 4 M M O M M O M O M O 3rd digit 4 M 5 P P I P P I P I P I 5 P 6 C C R C C R C R C R 6 C 7 Y Y Z Y Y Z Y Z Y Z 7 Y 8 F F D F F D F D F D 8 F 9 S S A S S A S A S A 9 S 0 V V V T V V T V T T 0 V 1 X X X B X X B X B B 1 X 2 Q Q Q U Q Q U Q U U 2 Q 3 K K K E K K E K E E 3 K 5th digit 4 M M M 0 M M O M O O 4th digit 4 M 5 P P P I P P I P I I 5 P 6 C C C R C C R C R R 6 C 7 Y Y Y Z Y Y Z Y Z Z 7 Y 8 F F F D F F D F D D 8 F 9 S S S A S S A S A A 9 S 110 Rec. 491-1 ANNEX. II TRANSLATION BETWEEN A 9-DIGIT IDENTITY NUMBER AND A 7-SIGNAL IDENTITY A 9-digit identity number is translated into a 7-signal identity by following the procedure described below: Step 1 : Divide the 9-digit number by 20 resulting in an integer I 1 and a remainder Rl; Step 2 : If the resulting integer is unequal to zero, divide the integer again by 20 resulting in a new integer (I 2) and a new remainder (R2); Step 3 : Repeat Step 2 until the resulting integer becomes zero; this will require up to seven divisions; Step 4 : If the integer becomes zero before seven divisions have been carried out, the remainders yet to be obtained shall be set to zero (e.g. if I 4 is the first integer which is zero, then R5, R6 and R7 will all be zero); Step 5 : Translate the remainders R l, R2, R3, R4, R5, R6 and R7, into the identification signals IS7, IS6, IS5, IS4, IS3, IS2 and IS1, respectively, in accordance with Table III. A 7-signal identity is converted into a 9-digit identity number by following the procedure described below: Step 1 : Convert IS1-IS7 to the numerical values R7-R1 respectively using Table III. Step 2 : The 9-digit identity number is then given by the following formula: 9-digit No. = 20°R1 + 20R2 + 202R3 + 203R4 + 204R5 + 205R6 -I- 206R7. Rec. 491-1 111 T A B L E III Identification R em ainder signal (R) (IS) 0 V l X 2 Q 3 K 4 M 5 P 6 C 7 Y 8 F 9 S 10 T 11 B 12 U 13 E 14 0 15 I 16 R 17 Z 18 D 19 A Exam ple: The 9-digit number 364775427 is transmitted as: Call block 1: P (RQ) E Call block 2: (RQ) A R Call block 3: D B Y 364775427 divided by 20 results in I 1 = 18238771 and R l = 7 -*• IS7 = Y 18238771 divided by 20 results in I 2 = 911938 and R 2 = 11 -► IS6 = B 911938 divided by 20 results in I 3 = 45596 and R3 = 18 IS5 = D 45596 divided by 20 results in I 4 = 2279 and R 4 = 16 -► IS4 = R 2279 divided by 20 results in I 5 = 113 and R5 = 19 -+ IS3 = A 113 divided by 20 results in I 6 = 5 and R 6 = 13 -► IS2 = E 5 divided by 20 results in I 7 - 0 and R7 = 5 IS1 = P 112 Rec. 492-4 RECOMMENDATION 492-4* OPERATIONAL PROCEDURES FOR THE USE OF DIRECT-PRINTING TELEGRAPH EQUIPMENT IN THE MARITIME MOBILE SERVICE (Question 5/8) (1974-1978-1982-1986-1990) The CCIR, CONSIDERING (a) that narrow-band direct-printing telegraph services are in operation using equipment as described in Recommendations 476 and 625; (b) that an improved narrow-band direct-printing telegraph system providing automatic identification and capable of using the 9-digit ship station identity is described in Recommendation 625; (c) that the operational procedures necessary for such services should be agreed upon; (d) that, as far as possible, these procedures should be similar for all services and for all frequency bands (different operational procedures may be required in the frequency bands other than the HF and MF bands); (e) that a large number of equipments complying with Recommendation 476 exist; '(f) that interworking between equipments in accordance with Recommendations 476 and 625 is required, at least for a transitionary period, UNANIMOUSLY RECOMMENDS that the following operational procedures in the MF and HF bands for 'the use of narrow-band direct-printing telegraph equipment in accordance with either Recommendation 476 or 625 in the maritime mobile service should be observed: 1. Mode A (ARQ) 1.1 Methods used for setting up narrow-band direct-printing telegraph communications between a ship station and a coast station in the ARQ-mode should be on a fully automatic or semi-automatic basis, insofar that a ship station should have direct access to a coast station on a coast station receiving frequency and a coast station should have direct access to a ship station on a coast station transmitting frequency; 1.2 however, where necessary, prior contact by Morse telegraphy, radiotelephony or other means is not precluded; 1.3 through connection to a remote teleprinter station over a dedicated circuit or to a subscriber of the international telex network may be achieved by manual, semi-automatic or automatic means; Note 1 — Before an international automatic service can be introduced, agreement has to he reached on a numbering plan, traffic routing and charging. This should be considered by both the CCITT and the CCIR. Note 2 — Recommendations 476 (see § 3.1.5) and 625 (see § 3.8) make provision for automatic re-establishment of radio circuits by rephasing in the event of interruption. However, it has been reported that this procedure has, in some countries, resulted in technical and operational problems when radio circuits are extended into the public switched network or to certain types of automated switching or store-and-forward equipments. For this reason, some coast stations do not accept messages if the rephasing procedure is used. Note 3 — When a connection is set up in the ARQ mode with the international telex network via a coast station, where practicable the general requirements specified in CCITT Recommendation U.63 should be met. * The Director, CCIR, is requested to bring this Recommendation to the attention of the IMO, CCITT and the Secretary-General, ITU. Rec. 492-4 113 1.4 when, by prior arrangement, unattended operation is required for communication from a coast station to a ship station, or between two ship stations, the receiving ship station should have a receiver tuned to the other station’s transmitting frequency and a transmitter tuned or a transmitter capable of being tuned automatically to the appropriate frequency and ready to transmit on this frequency; 1.5 for unattended operation a ship station should be called selectively by the initiating coast or ship station as provided for by Recommendations 476 and 625. The ship station cqncerned could have available traffic stored ready for automatic transmission on demand of the calling station; 1.6 at the “over” signal, initiated by the calling station, any available traffic in the ship’s traffic store could be transmitted; 1.7 at the end of the communication, an “end of communication” signal should be transmitted, whereupon the ship’s equipment should automatically revert to the “stand-by” condition; 1.8 a “free channel” signal may be transmitted by a coast station where necessary to indicate when a channel is open for traffic. The “free channel” signals should preferably be restricted to only one channel per HF band and their duration should be kept as short as possible. In accordance with Article 18 of the Radio Regulations arid recognizing the heavy loading of the frequencies available for narrow-band direct printing in the HF bands, “free channel” signals should not be used in future planned systems; 1.9 the format of the “free channel” signal should be composed of signals in the 7-unit error detecting code as listed in § 2 of Annex I to Recommendation 476 and § 2 of Annex I to Recommendation 625. Three of these signals should be grouped into a block, the middle signal being the “signal repetition” (RQ), the first signal of the block being any of the signals VXKMCF TBOZA and the third signal of the block being any of the signals VM PCYFS OIRZDA (see Recommendation 491). These signals should be indicated in the ITU List of Coast Stations. Selections of new signals should preferably be chosen to correspond to the First two digits of that coast station’s 4-digit identification number. If this is not possible because the characters needed are not listed above, or if this is not desired because this combination is already in use by another coast station, it is preferred that a combination of characters be selected from those listed above in the second part of each row, i.e. TBOZA for the first signal and OIRZDA for the third signal of the free channel block. The signals in the block are transmitted at a modulation rate of 100 Bd and the blocks are separated by pauses of 240 ms. For manual systems this “free channel” signal should be interrupted either by a period of no signal or by a signal or signals, that would enable an operator to recognize the “free channel” condition by ear. An aurally recognizable signal, e.g. a Morse signal, may be used alone as the “free channel” signal in manual systems. At least 8 blocks of the 7-unit signal should be transmitted before interruption; 1.10 in the case of single frequency operation, the free channel signal should be interrupted by listening periods of at least 3 s; 1.11 general operational procedures for setting up calls between ship stations and coast stations are given in Annex I; 2. Mode B (FEC) 2.1 Messages could, by prior arrangement, be sent in the B mode from a coast station or ship to a number of ships or to a single ship, preceded if desired by the selective call code of the ship(s) concerned where: 2.1.1 a receiving ship station is not permitted or not able to use its transmitter, or 2.1.2 communications are intended for more than one ship, or 2.1.3 unattended reception of the B mode is required and automatic acknowledgement is not necessary; in such cases, the ship station receivers should be tuned to the appropriate coast or ship station transmitting frequency; 114 Rec. 492-4 2.2 all B mode messages should start with “carriage return” and “line feed” signals; 2.3 when the ship station receives phasing signals in the B mode, its teleprinter should start automatically and should stop automatically when reception of the emission ceases. 3. Inter-working between equipments in accordance with Recommendations 476 and 625 Recommendation 625 provides for automatic inter-working with equipment which is in accordance with Recommendation 476. The criteria for determining whether one or both stations are of the Recommendation 476 type are the length of the call signal and the composition of the call blocks. If both stations have equipment in accordance with Recommendation 625, automatic station identification is a part of the automatic call set-up procedures. However, if one or both stations have equipment in accordance with Recommendation 476, no automatic station identification takes place. For this reason, and because Recom mendation 625 accommodates the use of the 9-digit ship station identity for the direct-printing equipment call signal, it is desirable that all new equipment be in accordance with Recommendation 625 at the earliest practicable time. _ In order to attain full compatibility with the large number of existing equipment, it will be necessary to assign both a 9-digit and a 5- (or 4-) digit identity (i.e. 7- and 4-signal call signals) to such new stations. Ship and coast station lists should contain both signals. Rec. 492-4 115 ANNEX I 1. Procedure for setting up a call in the ship-to-coast station direction Coast station Step Ship station I \ i 1 Ship initiates the call Exchange answer-backs (') < s i GA t +? (’) < = MSG r + (*•») or < = TLX t xy + (2-2) or < = DIRTLX t xy + (J-3) or < = TGM t + (*•«) or URG t + (*•») or < = RTLt + 0 ;‘) or < = OPR t + (2-2) or < = wx t + (2 «) or < = NAV t + (2-») or < = STA t + (2-10) or < = POS t + 3 (2u )or FREQ T + | (2-12) or < = SVC T + " (213) or MAN t + I (2,u) or MED t + (2-ls) or < = OBS T + (21S) or < = HELPt + (2-” )or < = HELP... t + (21*) or < = AMV r + (2-19) or < = BRKt + (2 2°) or 1 MULT LX t xy/xy/xy + (221)o r . < = STS t x + (2-22) or < = INF r + (2-23) or < = VBTLX t xy + (2 M) or < = FAX t xy + (2 2S) or < = TEL t xy + (2,2‘) or < = DATA T xy + (**"> ?(3) < s jQRC t +? ship transmits its AAIC, followed by + ?(3) (4) < = I MSG t + ? ( s) Message procedure (6) 10 < = i k k k k ( 7) 11 Exchange answer-backs (*) 12 < = “Message reference charged time, etc.” (*) 13 < S 4. GA t +? ______ 14 Go to step 4 or end of communication 116 Rec. 492-4 2. Procedure for setting up a call in the coast-to-ship station direction Operation in the direction coast station to. ship may need to be in the store-and-forward mode owing to the fact that radio propagation conditions may not allow the setting up of a call at the intended time. Coast station Step Ship station ! i _ ! Coast station initiates ^ , call . | _ _ 2 . Exchange answer-backs (') ______3 ______Message procedure (6 ) 4 ______Exchange answer-backs (!) Go to step 3 __ :______® or = 1 GA t + ? ______6 . • ______7 ______If ship has traffic for coast station go to step 4 of Part 1 or end of communication FIGURE 1 - Algorithm for ship stations working with coast stations operating in automatic mode Notes relative to Fig. 1: 0) a) In automatic operation the answer-back exchange is initiated and controlled by the coast station. For calls set up by the ship station the answer-back exchange in manual operation may be initiated by the ship station. For calls set up by the coast station the answer-back exchange in manual operation is initiated by the coast station, thereby defining the order in which the exchange takes place. b) Answer-back code as defined in CCITT Recommendations F.l30 for ship stations and F.60 for coast stations. (2) A coast station need not provide all of the facilities indicated. However, where specific facilities are provided, the facility codes indicated should be used. The facility “HELP” should always be available. (21) MSG indicates that the ship station needs to immediately receive any messages held for it at the coast station. (22) TLXfxy indicates that the following message is for immediate connection to a store-and-forward facility located at the coast station. y indicates the subscriber’s national telex number. x is used where applicable to indicate the country code (CCITT Recommendation F.69) preceded by 0 (when applicable). (Where the store-and-forward system is remote from the coast station, TLX alone may be used.) TLXA may optionally be used instead of TLX which indicates that ship wishes to be advised (using the normal shore-to-ship procedures) when the message has been delivered to the indicated telex number. Rec. 492-4 117 DIRTLXfxy indicates that a direct telex connection is required, y indicates the subscriber’s national telex number. x is used where applicable to indicate the country code (CCITT Recommendation F.69) preceded by 0 (when applicable). RDL+ may optionally be used to indicate that the last DIRTLXfxy telex number should be redialled. TGM indicates that the following message is a radio telegram. URG indicates that the ship station needs to be connected immediately to a manual assistance operator and an audible alarm may be activated. This code should only be used in case of emergency. RTL indicates that the following message is a radio telex letter. OPR indicates that connection to a manual assistance operator is required. WX indicates that the ship station needs to immediately receive weather information. NAV indicates that the ship station needs to immediately receive navigational warnings. STA indicates that the ship station needs to immediately receive a status report of all store-and-forward messages which have been sent by that ship station, but which the ship station has not already received on retransmitted or non-delivered information (see also (6)). STAfx may also be used where the ship station needs to immediately receive a status report of such a message where x indicates the message reference provided by the coast station. POS indicates that the following message contains the ship’s position. Some administrations use this information to assist in the subsequent automatic transmission or reception of messages (e.g. for calculating the optimum traffic frequency and/or the appropriate directional antennas to use). FREQ indicates that the following message indicates the frequency on which the ship is keeping watch. SVC indicates that the following message is a service message (for subsequent manual attention). MAN indicates that the following message is to be stored and manually forwarded to a country which cannot be accessed automatically. MED indicates that an urgent medical message follows. OBS indicates that the following message is to be sent to the meteorological organization. HELP indicates that the ship station needs to immediately receive a list of available facilities within the system. If information is needed on the application of procedures for individual facilities at a coast station, request for further details concerning the specific procedure can be obtained by the facility code HELP followed by the appropriate facility code for which the information is needed, e.g.: < =|.HELP DIRTLXf + indicates that the ship station needs information on the procedures (action by ship operator) for ordering a dialogue-mode connection with a telex network subscriber via the coast station. AMV indicates that the following message is to be sent to the AMVER organization. BRK indicates that the use of the radio path is to be immediately discontinued (for use where the ship’s operator can only use a teleprinter for controlling the ARQ equipment). M ULTLX|xy/xy/xy+ indicates that the following message is a multiple address message for immediate connection to a store-and-forward facility located at the coast station. y indicates the subscriber’s national telex umber. x is used where applicable to indicate the country code (CCITT Recommendation F.69) preceded by 0 (when applicable). Each separate xy indicates a different telex number to which the same message should be forwarded. At least two separate telex numbers should be included. MULTLXA may optionally be used instead of MULTLX which indicates that the ship wishes to be advised (using the normal shore-to-ship procedures) when the messages have been delivered to the indicated telex numbers. STSjx+ indicates that the following message is for transmission to a ship using a store-and-forward facility located at the coast station, x indicates the addressed ship’s 5- or 9-digit identity number. INF indicates that the ship station needs to immediately receive information from the coast station’s database. Some administrations provide a variety of different database information in which case INF returns a directory listing and a subsequent facility code is used to select the desired information. VBTLXjxy indicates that the following message should be dictated, by the coast station, to a voicebank (voice messaging) telephone number for subsequent retrieval by the addressee, and that a copy of the message should be forwarded to telex number xy. The voicebank telephone number should be included in the first line of the message text. FAXfxy indicates that the following message should be forwarded, via the PSTN, by facsimile to the telephone number xy. 118 Rec. 492-4 (226) TELfxy indicates that the following message should be telephoned, by the coast station, to the telephone number xy. (227) DATAfxy indicates that the following message should be forwarded by the coast station using data facilities to the subscriber number xy (via the PSTN). (3) The symbol “?” is not necessary where the coast station is automatic. It is normally required only for manual systems. (4) In cases where the coast station requires information about the relevant Accounting Authority Identification Code (AAIC), this information should be provided by the ship operator on receipt of the combination < = JQRCf + from the coast station. Some coast stations may request additional information, e.g. ship’s name, call sign, etc. (5) This sequence may be preceded where necessary by suitable prompts or facility selection information and, if appropriate, any consequent ship station reply, or may be deleted where not applicable (e.g. where facility codes WX, NAV, STA, MSG or HELP are input at step 4). Where facility code DIRTLXfxy was input at step 4, this sequence may be replaced by the distant end answer-back or by any service signal (e.g. NC, OCC, etc.) received from the telex network. (6) Message procedures depends on which facility is used: For TLX where the store-and-forward system is remote from the coast station, CCITT Recommendation F.72 may apply. Where the store-and-forward system is located at the coast station, the complete information content of the message sent at this step will be forwarded to the subscriber whose telex number is given by xy. For DIRTLX see CCITT Recommendation F.60. For TGM see CCITT Recommendations F.l and F.31. For SVC and MED the message will normally be plain text and no specific message procedure is required. For RTL the message will be plain text but should include the postal address of the addressee. For STA the appropriate status information is returned to the ship in accordance with CCITT Recommendation F.72, § 11.3 and § 11.4. For POS and FREQ specific national procedures may apply. (7) This sequence of 4 K’s “KKKK” (4 combination No. 11 signals in the letter case) indicates that any network connection should be cleared but that the radio path should be maintained and that the procedure should immediately proceed to step 11. This sequence may be used elsewhere in the procedure in which case the procedure reverts to step 3. (8) This step is optional and may not apply to all facilities. Rec. 540-2 119 RECOMMENDATION 540-2* OPERATIONAL AND TECHNICAL CHARACTERISTICS FOR AN AUTOMATED DIRECT-PRINTING TELEGRAPH SYSTEM FOR PROMULGATION OF NAVIGATIONAL AND METEOROLOGICAL WARNINGS AND URGENT INFORMATION TO SHIPS (Question 5/8) (1978-1982-1990) The CCIR, CONSIDERING (a) that the availability of navigational and meteorological warnings and urgent information on board ships is of great importance for safety; (b) that the existing radiocommunication system for promulgation of navigational and meteorological warn ings and urgent information to ships can be improved by use of modern techniques; (c) that the IMO has etablished the following definitions on the promulgation of maritime safety information: — “NAVTEX” means the system for the broadcast and automatic reception of maritime safety information by means of narrow-band direct-printing telegraphy ; — “international NAVTEX service” means the coordinated broadcast and automatic reception on 518 kHz of maritime safety information by means of narrow-band direct-printing telegraphy using the English language, as set out in the NAVTEX manual, published by the IMO; — “national NAVTEX service” means the broadcast and automatic reception of maritime safety information by means of narrow-band direct-printing telegraphy using frequencies and languages as decided by the adminis trations concerned; (d) that the 1988 Amendments to the International Convention for the Safety of Life at Sea, 1974, require that every ship to which the Convention applies shall be provided with a receiver capable of receiving international NAVTEX service broadcasts; (e) that several countries are operating a coordinated international NAVTEX service, based on narrowband direct-printing in accordance with Article 14A of the Radio Regulations; (f) that the system should be applicable to the maritime mobile service (both international and national); (g) that it is desirable that the service fulfils the requirements of all types of ships desiring to use it; .(h) that although each area may need specific guidance, the use of standard technical and operational characteristics would facilitate the extension of the service, UNANIMOUSLY RECOMMENDS 1. that the operational characteristics for the promulgation of navigational and meteorological warnings and urgent information using NBDP should be in accordance with Annex I; 2. that the technical characteristics for the promulgation of navigational and meteorological warnings and urgent information using NBDP should be in accordance with Annex II. The Director, CCIR, is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO), the International Hydrographical Organization (IHO), the World Meteorological Organization (WMO) and to the International Association of Lighthouse Authorities (IALA). 120 Rec. 540-2 ANNEX I OPERATIONAL CHARACTERISTICS 1. Narrowband direct-printing techniques should be used for an automated telegraph system for promulga tion of navigational and meteorological warnings and urgent information to ships. Common frequencies for such transmissions should be internationally agreed upon and the frequency 518 kHz has been designated for world-wide use in the international NAVTEX service (see Radio Regulations Nos. 474, 2971B and N2971B). 1.1 For national NAVTEX services administrations should also utilize the format of this Recommendation on the appropriate frequencies as defined in the Radio Regulations. 2. The radiated power from the coast station transmitter should only be that sufficient to cover the intended service area of that coast station. The range extension occurring during night hours should also be considered. 3. The information transmitted should primarily be of the type used for coastal waters preferably using a single frequency (Resolution No. 324 (Mob-87)). 4. The transmission time allocated to each station should be restricted to that which is adequate for the anticipated messages to be broadcast to the area concerned. 5. Scheduled broadcasts should take place at intervals not exceeding eight hours and be coordinated, to avoid interference with broadcasts from other stations. 6. Message priorities 6.1 Three message priorities are used to dictate the timing of the first broadcast of a new warning in the NAVTEX service. In descending order of urgency they are: — VITAL: for immediate broadcast, subject to avoiding interference to ongoing transmissions; — IMPORTANT: for broadcast at the next available period when the frequency is unused; — ROUTINE: for broadcast at the next scheduled transmission period. Note — Both VITAL and IMPORTANT warnings will normally need to be repeated, if still valid, at the next scheduled transmission period. 6.2 In order to avoid unnecessary disruption to the service, the priority marking VITAL is to be used only in cases of extreme urgency, such' as some distress alerts. In addition, VITAL messages are to be kept as brief as possible. 6.3 Periods should be scheduled between the regular transmission periods permitting immediate/early trans mission of VITAL messages. 6.4 By use of the message serial number 00 in the preamble of a message (see also Annex II § 6) it is possible to override any exclusion of coast stations or of message types which might have been made in the receiving equipment. 7. Initial shore-to-ship distress-related messages should first be broadcast on the appropriate distress frequency by coast stations in' whose SAR area distress cases are handled. 8. Participating transmitting stations should be provided with monitoring facilities to enable them to: — monitor their own transmissions as to signal quality and transmission format; — confirm that the channel is not occupied. 9. In case a message is repeated by more than one transmitting station within the same NAVTEX region (e.g. for better coverage) the original preamble Br B4 (see Annex II) should be used. 10. In order to avoid overloading of the channel it is desirable to use a single language and where a single language is used it shall be English. 11. Dedicated on-board equipment is recommended. 12. Other operational characteristics and detailed guidance are given in the NAVTEX Manual developed by the International Maritime Organization. Rec. 540-2 121 ANNEX II TECHNICAL CHARACTERISTICS 2. The signals transmitted should be in conformity with the collective B-mode of the direct-printing system specified in Recommendations 476 and 625. 3. The technical format of the transmission should be as follows: Carriage Carriage return Phasing signals One 1 2 3 4 return >10 s ZCZC space B B B B + Message NNNN 4- line feed 2 line feeds -/A “ I 7 ” “ [ “ 1 Carriage J ~ ” T T Carriage return ind of emissions Phasing signals Idle signals ZCZC I space I » W W j r e tr I Message I NNNN I + a a ...a > 5s 2 line feeds > 2 s _ L I______L L J______/ / - in which ZCZC defines the end of the phasing period, the Bi character is a letter (A-Z) identifying the transmitter coverage area, the B2 character is a letter (A-Z) for each type of message. 2.1 Both the Bt characters identifying the different transmitter coverage areas and the B2 characters identifying the different types of messages are defined by IMO and chosen from Table I of Recommendations 476 and 625, combination numbers 1-26. 2.1.1 Ship equipment should be capable of automatically rejecting unwanted information using char acter Bj. 2.1.2 Ship equipment should be capable of disabling print-out of selected types of messages using character B2 with the exception of messages with B2 characters A, B and D (see also § 2.1). 2.1.3 If any facility is rejected or disabled as described in § 2.1.1 and 2.1.2 above, the extent of any such limitation must be clearly indicated to the user. 2.2 B3B4 is a two-character serial number for each B2, starting with 01 except in special cases where the serial number 00 is used (see § 6 below). 2.3 The characters ZCZC BiB2B3B4 need not be printed. 3. The printer should only be activated if the preamble Br B4 is received without errors. 4. Facilities should be provided to avoid printing of the same message several times on the same ship, when such a message has already been satisfactorily received. 5. The necessary information for the measures under § 4 above should be deduced from the sequence BiB2B3B4 and from the message. 6. A message should always be printed if B3B4 = 00. 7. Extra (redundant) letter and figure shifts should be used in the message to reduce garbling. 8. In case a message is repeated by another transmitting station (e.g.for better coverage) the original preamble Br B4 should be used. 9. The equipment on board ships should be neither unduly complex nor expensive. 10. The transmitter frequency tolerance for the mark and the space signals should be better than ± 10 Hz. 122 Rec. 688 RECOMMENDATION 688* TECHNICAL CHARACTERISTICS FOR A HIGH FREQUENCY DIRECT-PRINTING TELEGRAPH SYSTEM FOR PROMULGATION OF HIGH SEAS AND NAVTEX-TYPE MARITIME SAFETY INFORMATION ^Question 5/8) (1990) The CCIR, CONSIDERING , ' (a) the 1988 amendments to the International Convention for the Safety of Life at Sea, 1974, which permits ships, engaged exclusively on voyages in areas where an HF direct-printing telegraphy maritime safety information service is provided and which are fitted with equipment capable of receiving such service, to be exempted from the requirement to carry a radio facility for the reception of maritime safety information by the INMARSAT enhanced group calling systems; (b) that the World Administrative Radio Conference for Mobile Services, Geneva, 1987, allocated an exclusive narrow-band direct-printing channel on the frequencies 4210 kHz, 6314 kHz; 8416.5 kHz, 12 579 kHz, 16 806.5 kHz, 19 680.5 kHz, 22 376 kHz and 26 100.5 kHz, which could meet this requirement; (c) that the World Administrative Radio Conference for Mobile Services, Geneva, 1987, also allocated an exclusive narrow-band direct-printing channel on the frequency 4209.5 kHz for NAVTEX-type transmissions; (d) Recommendation 540 — Operational and technical characteristics for an automated direct-printing telegraph system for promulgation of navigational and meteorological warnings and urgent information to ships, i.e. the international NAVTEX system, operating on 518 kHz, UNANIMOUSLY RECOMMENDS that both the technical characteristics for transmitting high seas maritime safety information using HF NBDP on the frequencies of CONSIDERING (b), and the technical characteristics for transmitting NAVTEX- type navigational and meteorological warnings and urgent information to ships using 4209.5 kHz should be in accordance with Annex II of Recommendation 540. * The Director of CCIR is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO). Rec. 692 123 RECOMMENDATION 692 NARROW-BAND DIRECT-PRINTING TELEGRAPH EQUIPMENT USING A SINGLE-FREQUENCY CHANNEL (Question 5/8) (1990) The CCIR, CONSIDERING (a) that single-frequency channel operation is possible using the operating algorithm for narrow-band direct-printing telegraph equipment described in Recommendations 476 and 625; (b) that a changeover to single-frequency operation could make available additional radio channels in the MF and HF bands; (c) that investigations carried out in a number of countries have demonstrated that there is a real possibility of using narrow-band direct-printing equipment using single-frequency radio channels; (d) that no specific frequencies are allocated for NBDP single-frequency non-distress operation between ship and coast stations, but under the provisions of Article 9 (No. 961) of the Radio Regulations, coast station frequencies could be used for this purpose *, UNANIMOUSLY RECOMMENDS 1. that where possible and as an alternative to using two frequencies, use should be made in the maritime-mobile service of narrow-band direct-printing telegraph equipment operating in the ARQ mode on a single frequency, under the condition that no harmful interference is caused to other stations (see Article 9, No. 961 of the Radio Regulations) ; 2. that, in the case of single-frequency operation with narrow-band direct-printing equipment, the provisions and operating procedures indicated in Annex I should be applied. ANNEX I 1. Channels to be used for single-frequency operation between coast stations and ship stations should be indicated as such in the List of Coast Stations. 2. Also in the case of single-frequency operation, the procedures set forth in Recommendation 492 should be followed. 3. In ship-to-shore and shore-to-ship communications operations should be carried out on one of the coast station frequencies allocated for single-frequency operations. 4. In ship-to-ship communications operations should be carried out on one of the unpaired frequencies' allocated to ship stations for such operations. 5. The input circuits of a ship’s radio receiver used for single-frequency operations should effectively be protected against excessive HF voltages induced by the ship’s associated transmiter. 6. The radio receiver used at the master station (see Recommendation 625) (normally the ship) should have regained its full sensitivity sufficiently soon after the transmission period of the associated transmitter so as to be able to accommodate short distances between master and slave stations (see Recommendation 625, § 1.7). 7. The radio receiver used at the slave station (see Recommendation 625) (normally the coast station) should have regained its full sensitivity sufficiently soon after the transmission period of the associated transmitter. 8. The (noise) output from each transmitter used for this single-frequency operation should be sufficiently suppressed during transmission pauses to a level which ensures that the effective sensitivity of the associated radio receiver is not degraded. 9. The narrow-band direct-printing equipment should preferably be sensitive to input signals only during the time period when signals are expected to be received from the other station. * Administrations should take CONSIDERING (d) into account to the extent necessary when preparing their proposals for the next competent WARC. 124 Rec. 493-4 RECOMMENDATION 493-4* DIGITAL SELECTIVE-CALLING SYSTEM FOR USE IN THE MARITIME MOBILE SERVICE (Question 9/8) (1974-1978-1982-1986-1990) The CCIR, CONSIDERING (a) that selective calling in the shore-to-ship, ship-to-ship and ship-to-shore directions would expedite the handling of traffic in the maritime mobile service ; (b) that the International Maritime Organization (IMO) has listed a number of operational requirements that should be taken into account when designing a general purpose selective-calling system; (c) that chapter IV of the International Convention for the Safety of Life at Sea, 1974, as amended in 1988, requires the use of digital selective-calling for distress alerting and safety calling in the Global Maritime Distress and Safety System; (d) that neither the selective-calling system described in Recommendation 257, nor that forming part of the systems described in Recommendations 476 and 625 can fully meet the IMO recommended performance stan dards; (e) that several administrations have indicated an urgent need for a general purpose selective-calling system; (f) that several administrations have been developing different systems; (g) that the system should be applicable to the maritime mobile service, both for international and national needs; (h) that it is desirable that the selective-calling system fulfil the requirements of all types of vessels desiring to use it; (j) that Appendix 43 adopted by the World Administrative Radio Conference (Geneva, 1983) has provided for the use of maritime mobile service identities by all administrations, UNANIMOUSLY RECOMMENDS 1. that, where there is a need for a general purpose digital selective-calling system, the system should be designed in accordance with the characteristics given in Annex I; 2. that, where there is a need for simplified versions of DSC equipment, they should be designed in accordance with Annex II. * The Director, CCIR, is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO). ^ - Rec. 493-4 125 ANNEX I GENERAL PURPOSE EQUIPMENT CHARACTERISTICS 1. General 1.1 The system is a synchronous system using characters composed from a ten-bit error-detecting code as listed in Table I of this Annex. 1.1.1 The first seven bits of the ten-bit code of Table I of this Annex are information bits. Bits 8, 9 and 10 indicate, in the form of a binary number, the number of B elements' that occur in the seven information bits, a Y element being binary number 1 and a B element a binary number zero. For example, a BYY sequence for bits 8, 9 and 10 indicates 3(0 x 4 + 1 x 2 + 1 x 1) B elements in the associated seven information bit sequence; and a YYB sequence indicates 6(1 x 4 + 1 x 2 + 0 x 1)B elements in the associated seven information bit sequence. The order of transmission for the information bits is least significant bit first but for the check bits it is most significant bit first. 1.2 Time diversity is provided in the call sequence as follows: 1.2.1 Apart from the phasing characters, each character is transmitted twice in a time-spread mode; the first transmission (DX) of a specific character is followed by the transmission of four other characters before the re-transmission (RX) of that specific character takes place, allowing for a time-diversity reception interval of: 1.2.1.1 400 ms for HF and MF channels, and ' • 1.2.1.2 33 1/3 ms for VHF radio-telephone channels. 1.2.2 For a call which includes repetition(s) of the call sequence (see § 11.1), Fig. lc shows the transition between the end of one call sequence and the start of the following call sequence. 1.3 The classes of emission, frequency shifts and modulation rates are as follows: 1.3.1 FIB or J2B 170 Hz and 100 Bd for use on HF and MF channels. When frequency-shift keying is effected by applying audio signals to the input of single-sideband transmitters (J2B), the centre of the audio-frequency spectrum offered to the transmitter is 1700 Hz. 1.3.2 Frequency modulation with a pre-emphasis of 6 dB/octave (phase modulation) with frequency-shift of the modulating sub-carrier for use on VHF channels: — frequency-shift between 1300 Hz and 2100 Hz; the sub-carrier being at 1700 Hz; — the frequency tolerance of the 1300 Hz and 2100 Hz tones is ± 10 Hz; — the modulation rate is 1200 Bd; — the index of modulation is 2.0 ± 10%. 1.3.3 The radio-frequency tolerances of new designs of both transmitters and receivers in the MF and HF bands should be: — Coast station ± 10 Hz — Ship station ± 10 Hz — Receiver bandwidth should not exceed 300 Hz. Initially the following tolerances could apply (to permit the use of existing equipment to improve reliability, special measures may need to be taken at coast stations (see Report 501)): — Coast station ±15 Hz — Ship station ± 40 Hz — Receiver bandwidth should not exceed 340 Hz. X 1.4 The higher frequency corresponds to the B-state and the lower frequency corresponds to the Y-state of the signal elements. 126 Rec. 493-4 1.5 The information in the call is presented as a sequence of seven-bit combinations constituting a primary code. 1.5.1 The seven information bits of the primary code express a symbol number from 00 to 127, as shown in Table I, and where: 1.5.1.1 the symbols from 00 to 99 are used to code two decimal figures according to Table II; 1.5.1.2 the symbols from 100 to 127 are used to code service commands (see Table III). 1.6 The receiver decoder should provide maximum utilization of the received signal, including use of the error-check character. 1.7 Where the call repetitions described in § 11.1 apply, the following conditions are considered necessary: 1.7.1 the transmitter encoder must provide repetitive transmission of the call sequence in accordance with § 11.1; and 1.7.2 the receiver decoder should provide maximum utilization of the received signal, including use of the error-check character and by using an iterative decoding process with adequate memory provision. 2. Technical format of a call sequence 2.1 The technical format of the call sequence is: Dot pattern Phasing sequence Format specifier Address Category Self-identification Error-check Message 1 Message 2 Message 3 Message 4 * • • • End of sequence character * Distress calls only. 2.2 Examples of typical call sequences and the construction of the transmission format are given in Tables IV, V, VI and VII, and in Figs. 1, 2, 3 and 4. 2.3 The flow-charts illustrating the operation of the digital selective-calling system are shown in Figs. 5a and 5b. 3. Dot pattern and phasing 3.1 The phasing sequence provides information to the receiver to permit correct bit phasing and unambiguous determination of the positions of the characters within a call sequence. Note — Acquisition of character synchronization should be achieved by means of character recognition rather than, for example, by recognizing a change in the dot pattern, in order to reduce false synchronization caused by a bit error in the dot pattern. 3.2 The phasing sequence consists of specific characters in the DX and RX positions transmitted alternatively. Six DX characters are transmitted. 3.2.1 The phasing character in the DX position is symbol No. 125 of Table I. 3.2.2 The phasing characters in the RX position specify the start of the information sequence (i.e. the format specifier) and consist of the symbol Nos. Ill, 110, 109, 108, 107, 106, 105 and 104 of the Table I, consecutively. 3.3 Phasing is considered to be achieved when two DXs and one RX, or two RXs and one DX, or, if practical three RXs in the appropriate DX or RX positions, respectively, are successfully received. Rec. 493-4 127 3.4 To provide appropriate conditions for earlier bit synchronization and to allow for scanning methods to monitor several HF and MF frequencies by ship stations, the phasing sequence should be preceded by a dot pattern (i.e. alternating B-Y sequence bit synchronization signals) with duration of: 3.4.1 200 bits At HF and MF, for “distress”, “distress acknowledgement”, “distress relay” and “distress relay acknowledgement” calls and for all calling sequences to ship stations. 3.4.2 20 bits At HF and MF, for all acknowledgement sequences (except distress acknowledgements and distress relay acknowledgements — see § 3.4.1) and for all calling sequences to coast stations (except distress relay calls — see § 3.4.1). At VHF for all calls. Note — In exceptional circumstances and only on national working frequencies the 200 bit dot pattern could also be included in acknowledgement sequences to ship stations. 4. Format specifier 4.1 The format specifier characters which are transmitted twice in both the DX and RX positions (see Fig. 1) are: 4.1.1 symbol No. 112 for a “distress” call (Radio Regulation No. 3086); or 4.1.2 symbol No. 116 for an “all ships” call; or 4.1.3 symbol No. 114 for a selective call to a group of ships having a common interest (e.g. belonging to one particular country, or to a single shipowner, etc.); or 4.1.4 symbol No. 120 for a selective call to a particular individual station; or 4.1.5 symbol No. 102 for a selective call to a group of ships in a particular geographic area; or 4.1.6 symbol No. 123 for a selective call to a particular individual station using the semi-automatic/auto matic service. 4.2 It is considered that receiver decoders must detect the format specifier character twice for “distress” calls and. “all ships” calls to effectively eliminate false alerting. For other calls, the address, characters provide additional protection against false alerting and, therefore, single detection of the format specifier character is considered satisfactory (see Table VIII). 5. Address 5.1 “Distress” calls and “all ships” calls do not have addresses since these calls are implicitly addressed to all stations (ship stations and coast stations). 5.2 For a selective call directed to an individual ship, to a coast station or to a group of stations having a common interest, the address consists of the characters corresponding to the station’s maritime mobile service identity, the sequence consisting of characters coded in accordance with Table II. Note — According to Appendix 43 to the Radio Regulations, maritime mobile service identities are formed of a series of nine digits, consisting of three digits of the Maritime Identification Digits (MID) and six more digits. These identifications are included in the address and self-identification parts of the call sequence and are transmitted as five characters C 5 C 4 C 3 C 2 C 1 , comprising the ten digits of: (X\, X2) (X3, X4) (X5, X6) (X7, X8) and (X9, X10) respectively, whereas digit Xi0 is always the figure 0 and reserved for future use. 128 Rec. 493-4 Example: MID X4 X5 X6 X7 X8 X9 being the ship station identity is transmitted by the digital selective calling equipment as: (M, I) (D, X4) (X5, X6) (X7, X8) (X9, 0) 5.3 For a selective call directed to a group of ships in a particular geographic area a numerical geographic coordinates address consisting of 10 digits (i.e. 5 characters), is constructed as follows (see Fig. 6): Note — In order to comply with commonly accepted practice, the order of entry and read-out should be: first latitude and then longitude. 5.3.1 the designated geographic area will be a rectangle in Mercator projection; 5.3.2 the upper left-hand (i.e. north-west) corner of the rectangle is the reference point for the area; 5.3.3 the first digit indicates the azimuth sector in which the reference point is located, as follows: 5.3.3.1 quadrant NE is indicated by the digit “0”, 5.3.3.2 quadrant NW is indicated by the digit “1”, 5.3.3.3 quadrant SE is indicated by the digit “2”, 5.3.3.4 quadrant SW is indicated by the digit “3”; 5.3.4 the second and third digits indicate the latitude of the reference point in tens and units of degrees; 5.3.5 the fourth, fifth and sixth digits indicate the longitude of the reference points in hundreds, tens and units of degrees; 5.3.6 the seventh and eighth digits indicate the vertical (i.e. north-to-south) side of the rectangle, A 6. Category 6.1 The “category” information is coded as shown in Table IX and defines the degree of priority of the call sequence. 6.2 For a “distress” call the priority is defined by the format specifier and no category information is included in the call sequence. 6.3 For safety related calls, the “category” information specifies: 6.3.1 distress (Radio Regulation No. 3134); or 6.3.2 urgency; or 6.3.3 safety. 6.4 For other calls, the “category” information specifies: J 6.4.1 ship’s business; to cater for shore-to-ship communications having priority category 6 as defined in No. 4441 of the Radio Regulations. Some coast stations do not use the ship’s business priority category; 6.4.2 routine. 7. Self-identification 7.1 The maritime mobile service identity assigned to the calling station, coded as indicated in § 5.2, is used for self-identification. Rec. 493-4 129 8. Messages The messages that are included in a call sequence contain the following message elements, which are listed in the order in which they would appear in each message: 8.1 For a “distress” call (see Table IV and Fig. 4a)) the distress information is contained in four messages in the following order: 8.1.1 message 1 is the “nature of distress” message, coded as shown in Table X, i.e.: 8.1.1.1 fire, explosion; 8.1.1.2 flooding; 8.1.1.3 collision; 8.1.1.4 grounding; 8.1.1.5 listing, in danger of capsizing; 8.1.1.6 sinking; 8.1.1.7 disabled and adrift; 8.1.1.8 undesignated distress; 8.1.1.9 abandoning ship; 8.1.1.10 EPIRB emission; 8.1.2 message 2 is the “distress coordinates” message, consisting of ten digits indicating the location of the vessel in distress, coded on the principles described in Table II, in pairs starting from the first and second digits: Note — In order to comply with commonly accepted practice, the order of entry and read-out should be: first latitude and then longitude. 8.1.2.1 The first digit indicates the quadrant in which the incident has occurred, as follows: 8.1.2.1.1 quadrant NE is indicated by the digit “0”, 8.1.2.1.2 quadrant NW is indicated by the digit “1”, 8.1.2.1.3 quadrant SE is indicated by the digit “2”, 8.1.2.1.4 quadrant SW is indicated by the digit “3”. 8.1.2.2 The next four figures indicate the latitude in degrees and minutes. 8.1.2.3 The next five figures indicate the longitude in degrees and minutes. 8.1.2.4 If “distress coordinates” cannot be included, the 10 digits following the “nature of distress” should be automatically transmitted as the digit 9 repeated 10 times. 8.1.3 Message 3 is the time indication (UTC) when the coordinates were valid consisting of four digits coded on the principles described in Table II, in pairs starting from the first and second digits. 8.1.3.1 The first two digits indicate the time in hours. 8.1.3.2 The third and fourth digits indicate the part of the hours in minutes. 8.1.3.3 If the time cannot be included the four time indicating digits should be transmitted automatically as “8 8 8 8”. 8.1.4 Message 4 is a single character to indicate the type of communication (telephone or teleprinter) which is preferred by the station in distress for subsequent exchange of distress traffic (Radio Regulation No. 3134). This character is coded as shown in Table XI. 130 Rec. 493-4 8.2 For other types of calls (see Table V and Figs. 2 and 3) except “distress relay”, “distress relay acknowledgement” and “distress acknowledgement” calls (see § 8.3), two messages are included in the following order: 8.2.1 message 1 is the “telecommand” information and consists of 2 characters (first and second telecommand) coded as shown in Tables XI and XII; 8.2.1.1 if no information additional to that conveyed by the first telecommand character is required, then the second telecommand signal should be symbol No. 126 (no information) — see Table XII; 8.2.1.2 if no telecommand information is used, symbol No. 126 is transmitted twice; 8.2.2 message 2 may contain two “channel or frequency message” elements, each of which always consists of three characters, “character 1”, “character 2” and “character 3”, indicating the proposed working frequency (in the F1B/J2B mode the assigned frequency should be used) in multiples of 100 Hz or the channel number coded in accordance with Table XIII or the ship’s position. Note — If only one channel or frequency message element is used, this indicates the called station receive channel or frequency or a two-frequency (paired) channel. A second channel or frequency message element may be used to designate the called station transmit channel or frequency. If the calling station indicates only the called station receive frequency (for broadcast mode transmissions) then the symbol No. 126 repeated 3 times should be transmitted instead of the called station transmit channel or frequency message element. If no “channel or frequency message” elements are used, the symbol No. 126 is transmitted six times. For calls using the semi-automatic/automatic VHF service (see Table VII) then only one “channel or frequency message” element is transmitted which indicates the paired channel number. In the absence of this element the symbol No. 126 should be transmitted three times. 8.2.2.1 Frequency information The frequency (in the F1B/J2B mode the assigned frequency should be used) in multiples of 100 Hz may only be indicated as such when the frequency is below 30 MHz. The three characters provide for the required six decimal digits. Character 1 represents the units (U) and tens (T) of 100 Hz, character 2 the hundreds (H) and thousands (M) and character 3 the tens of thousands (TM) and hundreds of thousands (HM) of 100 Hz. 8.2.2.2 Channel information 8.2.2.2.1 HF and MF channels If the HM digit is 3, this indicates that the number represented by the digits TM, M, H, T and U is the HF/MF working channel number (either single frequency or two frequency channels). 8.2.2.2.2 VHF channels If the HM digit is 9, this indicates that the number represented by the values of the digits M, H, T and U is the VHF working channel number. 8.2.2.3 Ship’s position information 8.2.2.3.1 Message 2 may contain the ship’s position, consisting of the digit 5 repeated two times and ten digits (five characters) indicating this position, coded in accordance with § 8.1.2 to 8.1.2.3 (see Table XIV). 8.2.2.3.2 If a reply to a calling sequence requesting ship’s position is required (see Fig. 3d) then message 2 consists of twelve digits (six symbols), the first of which should be coded in accordance with § 8.1.2 to 8.1.2.3 followed by one symbol No. 126. 8.2.2.3.3 Message 3 follows message 2 in this case and contains the time (UTC) when the coordinates were valid, coded as indicated in § 8.1.3 to'8.1.3.3. 8.2.3 Message 3 follows message 2 when using the DSC system for calls initiated by ship stations requiring a semi-automatic or automatic connection (see Table VII) and contains the public switched network number (e.g. telephone number). In this case the format specifier used is symbol No. 123. Rec. 493-4 131 8.2.3.1 This number is coded by up to nine symbols in a manner similar to that shown in Table II, except that the first character transmitted should be either symbol No. 105 Or No. 106 to indicate whether the network number contains an odd or even number of significant digits. As an example, the number 0012345 would be coded as symbol numbers 105 00 01 23 45 whereas the number 00123456 should be coded as symbol numbers 106 00 12 34 56. 8.3 For “distress relay” including shore-to-ship alerts, “distress relay acknowledgement” and “distress acknow ledgement” calls, the message formats are indicated in Figs. 4b) and 4c) respectively. 8.3.1 For a distress relay where the identity of the station in distress is unknown, the “identification of the station in distress” should be automatically transmitted as the symbol No. 126 five times. 8.4 For test calls on the exclusive distress and safety calling frequencies on MF and HF, the call sequence is given in Table VI (see also Recommendation 541, Annex I). Technical means should be included to prevent the transmission of this sequence on VHF. Furthermore, the first telecommand symbol No. 118 (see Table III) should only be capable of being inserted into the sequence given in Table VI. 9. End of sequence The “end of sequence” character is transmitted three times in the DX position and once in the RX position (see Fig. lb)). It is one of the three unique characters corresponding to symbol Nos. 117, 122 and 127 as follows: 9.1 symbol No. 117 if the call requires acknowledgement (Acknowledge RQ); 9.2 symbol No. 122 if the sequence is an answer to a call that requires acknowledgement (Acknowledge BQ); 9.3 symbol No. 127 for all other calls. 10. Error-check character 10.1 The error-check character is the final character transmitted and it serves to check the entire sequence for the presence of errors which are undetected by the ten-unit error-detecting code and the time diversity employed. 10.2 The seven information bits of the error-check character shall be equal to the least significant bit of the modulo-2 sums of the corresponding bits of all information characters (i.e. even vertical parity). The format specifier and the end of sequence characters are considered to be information characters. The phasing characters shall not be considered to be information characters. Only one format specifier character and one end of sequence character should be used in constructing the error-check character. The error-check character shall also be sent in the DX and RX positions. Automatic acknowledgement transmissions should not start unless the error-check character is received and decoded correctly. 11. Call repetitions 11.1 Normally a call attempt should consist of a single call sequence transmission (see Fig. lb)). However, in exceptional circumstances and only using national DSC frequencies (see Recommendation 541), up to five transmissions of the same call sequence may be transmitted in accordance with Fig. lc). 11.2 Distress calls must be transmitted as single calls preceded by a dot pattern. However, where a distress call attempt contains more than one consecutive distress call on the same frequency (see Recommendation 541, Annex I, § 3.1.3), these consecutive calls may be transmitted with no gap between the end of one call and the start of the dot pattern of the following call to enable bit synchronization to be maintained. 12. Audible alarm An audible alarm and visual indicator should be provided upon reception of a distress call or a call with category distress (see Recommendation 541, RECOMMENDS 3). DX/RX A B c D E F G H i Format Called party Category Self- Telecommand Frequency Frequency End of sequence Error-check Dot Phasing specifier address identification message message message character pattern sequence 3 identical DX characters 2 identical 5 characters 1 character 5 characters 2 characters 3 characters 3 characters 1 RX character 1 character characters a) Technical format of a typical routine message DX DX DX DX DX DX A A B1 B2 B3 B4 B5 C D1 D2 D3 D4 D5 E1 E2 FI F 2 F3 G1 G2 G3 H 1 H H Dot pattern RX RX RX RX RX RX RX RX A A B1 8 2 B3 B4 B5 c D1 D2 D3 D4 D5 E l E 2 FI F2 F3 G1 G2 G3 H 1 7 6 .5 4 3 2 1 0 b) Transmission sequence corresponding to Fig. la G3 DX G2 c) Transmission sequence for repetition of a call to the same address according to § 11.1 FIGURE 1 - Construction o f call sequence (a) Calling sequence Acknowledge RQ Format specifier D ot Phasing Telecommand (EOS) Error-check Address Category Self-identification 3 identical DX pattern sequence 2 identical and frequency character characters characters 8 characters 5 characters 1 character 5 characters 1 RX character 1 character (b) Reply sequence with confirmation Acknowledge BQ . D ot Phasing Telecommand (EOS) Error-check Format specifier Address Category Self-identification pattern sequence and frequency 3 identical DX character 2 identical 5 characters 1 character 5 characters 8 characters characters characters 1 RX character 1 character 1 i l •1.1 1 j j i Reply se(luence wRh new proposal Acknowledge BQ Format specifier New proposed D ot Phasing (EOS) Self-identification telecommand Error-check 2 identical Address Category 3 identical DX pattern sequence and/or frequency character characters characters 8 characters 5 characters 1 character 5 characters 1 RX character 1 character II 1 1 I j | | (d) Reply sequence with refusal Acknowledge BQ Telecommand Format specifier (EOS) D ot Phasing and frequency Error-check 2 identical Address Catetory, Self-identification 3 identical D X pattern sequence Unable to comply ■- character characters characters 5 characters 1 character 5 characters 8 characters 1 RX character 1 character FIGURE 2 - Examples o f a calling sequence and reply sequences for typical individual calls (a) Calling sequence polling Acknowledge RQ D ot Phasing Format specifier Telecommand (EOS) Error-check Address Category Self-identification * pattern sequence 2 identical polling 3 identical D X character characters 5 characters 1 character 5 characters 2 characters 6c characters 1 character 1 RX character (b) Reply sequence to polling Acknowledge BQ Format specifier D ot Phasing Telecommand (EOS) Error-check Address Category Self-identification * pattern sequence 2 identical polling 3 identical D X character characters characters 5 characters 1 character 5 characters 6c 1 character' 2 characters 1 RX character (c) Calling sequence to request ship’s position Tele Acknowledge RQ Dot Phasing Format specifier command (EOS) Error-check Address Category Self-identification * pattern sequence 2 identical ship’s 3 identical D X character characters 5 characters 1 character 5 characters position 6c characters 1 character 2 characters 1 RX character (d) Reply sequence to request for ship’s position Tele Acknowledge BQ Format specifier Co (EOS) D ot Phasing command Error-check Address Category Self-identification ordinates 3 identical D X pattern sequence 2 identical ship’s character characters characters ** Time *** 5 characters 1 character position 1 character 5 characters i RX character 2 characters 6 characters FIGURE 3 - Calling sequences and reply sequences for polling and ship's position * The symbol No. 126 repeated six times should be included, (see § 8.2.2, Note). ** See § 8.2.2.3.2 (6 characters). *** See § 8.2.2.3.3 (2 characters). ■ a) “Distress call” Format End of specifier sequence Dot Phasing Self- Nature of. Distress Tele 3 identical Error-check Time pattern sequence identification distress coordinates command* D X charac character 2 identical ters 1 R X 5 characters 1 character 5 characters 2 characters 1 character 1 character characters character b) Distress relay and distress relay acknowledgement End of Format sequence Identification *** Phasing specifier Address Category Self- Telecommand Nature o f Distress Tele Error-check Dot o f ship Time 3 identical sequence ** (distress) identification distress relay distress coordinates command* character 493-4 Rec. pattern 2 identical in distress D X charac 5 characters 2 characters 1 character ters 1 RX 1 character characters 5 characters 1 character 1 character 5 characters 1 character 5 characters character c) Distress acknowledgement - Format End of sequence specifier Telecommand Identification Dot Phasing Category Self- Nature o f Distress Tele Error-check distress acknow o f ship Time All ships distress coordinates command* , 3 identical character pattern sequence (distress) identification D X charac 2 identical ledgement in distress 2 characters 1 character ters 1 RX characters 1 character 5 characters 1 character 5 characters 1 character 5 characters 1 character ' character FIGURE 4 - Sequences o f “distress call”, distress relay call and distress acknowledgement and distress relay acknowledgement * Type of subsequent communication (radiotelephony or teleprinter - see Table X and § 8.1.4). ** Address is not included if the format specifier is “all ships”. *** If the format specifier is “all ships” then the “end of sequence” character is symbol No. 127. For a distress relay call addressed to an individual coast station, the “end of sequence” character is RQ (symbol No. 117). For a distress relay acknowledgement call transmitted by a coast station, the “ end of sequence” character is BQ (symbol No. 122). 136 Rec. 493-4 FIGURE 5a - Example o f operational flow-chart (’ ) This method may be used when either single channel receivers (without scanning) or multi-channel receivers are used. C ) This method is preferable when scanning receivers are used on DSC channels (see Report 908, Annex I). * Message composition flow-chart is shown in Fig. 5b. Rec. 493-4 137 For reply message, processor copies self-identification of received message. ** The self-identification of a calling sequence is automatically entered. *** This may be entered automatically. Rec. 493-4 a) = - 11° (South) A.a = 12° (East) A*P = 3° AA z 5° Format Category specifier 2 1 1 0 1 2 0 3 0 5 Sector A ip AX 10° (East) A Format 1 3 Category specifier 1 0 0 2 0 2 0 0 FIGURE 6 - Geographic coordinates Rec. 493-4 139 TA B L E I — Ten-bit error-detecting code Emitted signal and Emitted signal and Emitted signal and Sym bol S ym bol Sym bol bit position bit position bit position N o. N o. N o. 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 1 23456789 10 00 BBBBBBBYYY 43 YYBYBYBBYY 86 BYYBYBYBYY 01 YBBBBBBYYB 44 BBYYBYBYBB 87' YYYBYBYBYB 02 BYBBBBBYYB 45 YBYYBYBBYY 88 BBBYYBYYBB 03 YYBBBBBYBY 46 b y y y b y b b y y 89 YBBYYBYBYY 04 BBYBBBBYYB 47 YYYYBYBBYB 90 BYBYYBYBYY 05 YBYBBBBYBY 48 BBBBYYBYBY 91 YYBYYBYBYB 06 BYYBBBBYBY 49 YBBBYYBYBB 92 BBYYYBYBYY 07 YYYBBBBYBB 50 BYBBYYBYBB 93 YBYYYBYBYB 08 BBBYBBBYYB 51 YYBBYYBBYY 94 BYYYYBYBYB 09 YBBYBBBYBY 52 BBYBYYBYBB 95 YYYYYBYBBY 10 BYBYBBBYBY 53 YBYBYYBBYY 96 BBBBBYYYBY 11 YYBYBBBYBB 54 BYYBYYBBYY 97 YBBBBYYYBB 12 BBYYBBBYBY 55 YYYBYYBBYB 98 BYBBBYYYBB 13 YBYYBBBYBB 56 BBBYYYBYBB 99 YYBBBYYBYY 14 BYYYBBBYBB 57 YBBYYYBBYY 100 BBYBBYYYBB 15 YYYYBBBBYY 58 BYBYYYBBYY 101 YBYBBYYBYY 16 BBBBYBBYYB 59 YYBYYYBBYB 102 BYYBBYYBYY 17 YBBBYBBYBY 60 BBYYYYBBYY 103 YYYBBYYBYB 18 BYBBYBBYBY 61 YBYYYYBBYB 104 b B b y b y y Y b b 19 YYBBYBBYBB 62 BYYYYYBBYB 105 YBBYBYYBYY 20 BBYBYBBYBY 63 YYYYYYBBBY 106 BYBYBYYBYY 21 YBYBYBBYBB 64 BBBBBBVYYB 107 YYBYBYYBYB 22 BYYBYBBYBB 65 YBBBBBYYBY 108 BBYYBYYBYY 23 YYYBYBBBYY 66 BYBBBBYYBY 109 YBYYBYYBYB 24 BBBYYBBYBY 67 YYBBBBYYBB 110 BYYYBYYBYB 25 YBBYYBBYBB 68 BBYBBBYYBY 111 YYYYBYYBBY 26 BYBYYBBYBB 69 YBYBBBYYBB 112 BBBBYYYYBB 27 YYBYYBBBYY 70 BYYBBBYYBB 113 YBBBYYYBYY 28 BBYYYBBYBB 71 YYYBBBYBYY 114 BYBBYYYBYY 29 YBYYYBBBYY 72 BBBYBBYYBY 115 YYBBYYYBYB 30 BYYYYBBBYY 73 YBBYBBYYBB 116 BBYBYYYBYY . 31 YYYYYBBB YB 74 BYBYBBYYBB 117 YBYBYYYBYB . 32 BBBBBYBYYB 75 YYBYBBYBYY 118 BYYBYYYBYB 33 YBBBBYBYBY 76 BBYYBBYYBB 119 YYYBYYYBBY 34 BYBBBYBYBY 77 YBYYBBYBYY 120 BBBYYYYBYY 35 Y y b b b y b y b b 78 BYYYBBYBYY 121 YBBYYYYBYB 36 BBYBBYBYBY 79 YYYYBBYBYB 122 BYBYYYYBYB 37 YBYBBYBYBB 80 BBBBYBYYBY 123 YYBYYYYBBY 38 BYYBBYBYBB 81 YBBBYBYYBB 124 BBYYYYYBYB 39 YYYB BYB BYY 82 BYBBYBYYBB 125 YBYYYYYBBY 40 BBBYBYBYBY 83 YYBBYBYBYY 126 BYYYYYYBBY 41 YBBYBYBYBB 84 BBYBYBYYBB 127 YYYYYYYBBB 42 BYBYBYBYBB 85 YBYBYBYBYY B = 0 Order of bit transmission: bit 1 first. Y = 1 Rec. 493-4 TABLE II — Packing table for decimal numbers into ten-bit characters The digits for the TJG c3t/5 O3 X! O3 TJ X3 G v>cO 3 X3 *3 3 T3 O G G G O G JS 3 3 J3 ■ 3 G H DC $ s DC 1=5 H DC H D D2 D1 D2 Dl D2 Dl D2 Dl D2 Dl Character Character Character Character Character 5 4 ' ’ 3 2 1 Note — Character 1 is the last character transmitted The digit sequence D2-D1 varies from 00 to 99 inclusive in each character (character 1 to 5 inclusive). The character that represents a particular two-decimal figure is transmitted as the symbol number (see Table I) that is identical to that particular two-decimal figure. When the number consists of and odd number of decimal digits, a zero shall be added in front of the most significant position to provide an integral number of ten-bit characters. Rec. 493-4 141 TABLE III - Use o f symbol Nos. 100 to 127 Phasing and S y m b o l u n iq u e Format specifier C a te g o r y Nature of distress First telecommand Second telecommand N o . f u n c tio n s 1 0 0 R o u tin e Fire, explosion F3E/G3E simplex TP No reason given (') 10 1 F lo o d in g F3E/G3E duplex TP Congestion at maritime switching centre (’) 1 0 2 Geographical area C o llis io n ( 2) B u sy ( ') 103 G r o u n d in g P o llin g Queue indication (’) 104 Phasing RX-0 Listing, in danger Unable to comply Station barred (') p o s itio n of capsizing 105 Phasing RX-1 S in k in g End of call (3) No operator available (') p o s itio n 106 Phasing RX-2 S h ip ’s Disabled and adrift D a ta Operator temporarily p o s itio n b u sin e ss unavailable (')' 107 Phasing RX-3 Undesignated (2) Equipment disabled (') p o s itio n d istr e ss 108 Phasing RX-4 S a fe ty Abandoning ship ( 2) Unable to use proposed p o s itio n channel (') 109 Phasing RX-5 J 3 E T P Unable to use proposed p o s itio n m o d e (') 1 1 0 P h a sin g R X - 6 (V D is tr e s s Ships and aircraft according p o s itio n U r g e n c y acknowledgement to Resolution No. 18 fM o b -8 3 1 111 Phasing RX-7 H 3 E T P M edical transport p o s itio n 1 1 2 D istr e s s D istr e ss EPIRB emission Distress relay Pay-phone/public call office 113 F1B/J2B TTY-FEC (2) 114 Ships having common (2) (2) in te r e st 115 F1B/J2B TTY-ARQ D a t a V .21 116 A ll sh ip s F1B/J2B TTY D a t a V .2 2 117 Ack. RQ (EOS) ( 5) (5) 118 T e st (6) D a t a V .2 2 bis 119 . F1B/J2B TTY D a ta V .23 1 2 0 Individual stations A1A Morse TR D a t a V .2 6 bis 121 Reserved for national Ship position or D a t a V .2 6 ter non-calling purposes, location registration e.g. Report 1159 u p d a tin g 1 2 2 Ack. BQ (EOS) (5) (5). 123 Individual station A 1 A M o r se D a t a V .2 7 ter semi-automatic/auto- matic service 124 (4) F1C/F2C/F3C FAX D a t a V .3 2 125 P h a s in g D X (5) (5) p o s itio n 126 * N o information (7) No information (7) 127 EOS ( 5) <5> TR tape recorder Symbol transmitted in place of unused message information. TP t e le p h o n y TTY direct printing Currently unassigned when used with first telecommands other than symbol No. 104 — for future use. ARQ Rec. 476 or Rec. 625 equipment Currently unassigned — for future use. FAX f a c s i m i l e . EPIRB emergency position-indicating radio beacon Only used for semi-automatic/automatic service. Used in the automatic V H F/UH F service (Recommendation 586). Should EOS end of sequence not be used in any future expansion. (5) Should not be used in any future expansion. (6) S e e § 8.4. (7) See § 8.2.1.1 e't 8.2.I.2. 142 Rec, 493-4 TABLE IV — Call sequences of “distress call” and “all ships call” (2) (5) M essage (5) (1) (1 )* Form at Self- (1) Address C ategory EOS ECC specifier identification 1 2 3 4 (1) (5) . (2) (1) ** Distress call N ature Distress 127 ECC * 112 of distress coordinates Tim e 00-— — 99 100...... 124 00— ...... 99 D istress (2) (6) 112 Telecommand All ships call U rgency Frequency 00-— — 99 100...... 126 ECC 1 1 6 ’ 110 or channel except 00...... 99 ' . Safety 117, 122 not not EOS 108 and 125 used used 127 (): number of characters ECC: error-check character EOS: end of sequence * See § 9. ** Type of subsequent communication, see Table XI and § 8.1.4. T A B L E V — Call sequences of selective calls (2) ' (5) M essage (5) (1 )* F orm at (1) Self- (1) A ddress C ategory EOS ECC specifier identification 1 2 D istress (2) (6) EOS Geographical 112 127 area call 102 U rgency 00...... 99 110 Ack. RQ Safety Telecommand Frequency, Ships having 100 117 108 00------99 ...... 126 channel or ECC com m on sh ip ’s or interest call Ship’s business except See § 5 o f positiqn 114 106 117, 122 Ack. BQ A n nex I and 125 00...... 99 R ou tine 122 100 or Individual call 120 EOS ■ 127 ( ): number of characters ECC: error-Check character EOS: end of sequence * See § 9. Rec. 493-4 143 T A B LE VI — Call sequence of selective calls for testing the equipment used far distress and safety calls (2) (5) M essage (5) (1) (1) * (1) Form at Self- Address C ategory EOS ECC specifier identification 1 2 (2) (6) Ack. RQ First 117 telecommand Frequency Individual call Safety 00...... 99 00-...... 99 or channel or ECC 120 108 118; 126 second A ck. BQ transmitted telecommand 122 .126 six tim es (): number of characters ECC: error-check character EOS: end of sequence * See § 9. TA B LE VII — Call sequence of semi-automatic/automatic ship-to-shore call (2) (5) M essage (5) (1) Form at Self- (1 )* (1) Address Category EOS ECC specifier identification 1 2 3 (2) (6)** (2-9) VHF calls - first telecommand 100, 101, 104, 105, 106, A ck. RQ 121 or 124; Selection Frequency, 117 R outine M F/HF calls - information 105 123 0 0 - ...... 99 00------9 9 chann el or or ECC 100 first telecommand or 106 followed ship’s position 102 ... 124 except by 00-...... 99 Ack. BQ 00...... 99 110, 112, 117 or see § 8.2.3.1 122 122; second telecommand in accordance with Table X II (): number of characters ECC: error-check character EOS: end of sequence * See § 9. ** Only 3 for VHF calls. Rec. 493-4 TABLE VIII — Format specifier S ym bol Format specifier N o . '• 112 Distress call 116 All ships call Selective call to: 120 — Individual stations 102 — Ships in a particular geographic area 114 — Ships having a common interest 123 Semi-automatic/automatic service TABLE IX — C ategory Sym bol Category N o. Safety related: 112 D istress 110 U rgency 108 Safety O thers: 106 Ship’s business 100 R outine TA B LE X — Nature of distress Sym bol Nature of distress N o . 100 Fire, explosion 101 F lood in g 102 C ollision 103 G rou n ding 104 Listing, in danger of capsizing 105 Sinking 106 Disabled and adrift 107 Undesignated distress .108 Abandoning ship 112 EPIRB emission Rec. 493-4 145 TABLE XI — First telecommand character Sym bol Use and/or mode Terminal equipment N o . ( '). 100 F3E/G3E simplex T eleph on e 101 F3E/G3E duplex T eleph on e 102 (2) — 103 P olling - 104 Unable to comply (3) - 105 End of call (4) — 106 D ata (5) M odem 107 (2) ’ — 108 (2) ■ — 109 J3E T elep h on e > 110 Distress acknowledgement - 111 H 3E T eleph on e 112 Distress relay - 113 F1B/J2B FEC Teleprinter (6) 114 (2) - 115 F1B/J2B ARQ Telex/teleprinter (6) 116 FI B/J2B receive Teleprinter 118 Test (7) — ' 119 F 1B /J2B Teleprinter 120 A 1A M orse Tape recorder 121 Ship position or location registration updating - 123 A 1A M orse Morse key/head-set 124 F1C/F2C/F3C Facsimile machine 126 No information (8) — (’) Symbols 117, 122, 125 and 127 should not be used. (2) Currently unassigned — for future use. (3) One of second telecommand symbols 100-109 must follow (see Table XII). (4) Only used for semi-automatic/automatic service. (5) One of second telecommand symbols 115-124 should follow (see Table XII). (6) Equipment according to Recommendation 476 or 625. (7) See § 8.4. (8) See § 8.2.1.2. 146 Rec. 493-4 TABLE XII — Second telecommand character Sym bol For use with the following M eaning N o. ( 1) first telecommand signals 100 No reason given (2) 101 Congestion at maritime switching centre (2) 102 Busy (2) 103 Queue indication (2) 104 Station barred (2) 104 (Unable to comply) (3|) 105 No operator available (2) 106 Operator temporarily unavailable (2) / 107 Equipment disabled (2) 108 Unable to use proposed channel (2) 109 Unable to use proposed mode (2) 110 Ships and aircraft according to Resolution No. 18 (Mob-83) } Any except 104, 105, 106, 110, 112 or 118 111 Medical transport 112 Pay-phone public call office 100, 101, 109, 115 or 124 113 (4) — 114 (4) - 115 Data V.21 (5) 116 Data V.22 (5) 118 D ata V.22 b is(5) 119 Data V.23 (5) 106 (D ata) 120 D ata V.26 bis (?) 121 D ata V.26 ter(5) ' 123 D ata V.27 ter(5) 124 , Data V.32 (5) 126 No information (6) Any except 104, 110 or 112 (’) Symbols 117, 122, 125 and 127 should not be used. (2) Currently unassigned when used with first telecommands other than Symbol No. 104 — for future use. (3) When second telecommands 100 — 109 are given alternative assignments (see (2)) they may be used with first telecommands other than Symbol No. 104. (4) Currently unassigned — for future use. (5) Data communication in accordance with these CCITT Recommendations may require special provision at coast stations (see Report 584, § 5 and Report^ll58) and may not be practicable in all frequency bands. (6) See §8.2.1.1. Rec. 493-4 147 TABLE XIII — Frequency or channel information 0 X X X X X The frequency in multiples of 100 Hz as indicated by the 1 X X X X X figures for the digits HM, TM, M, H, T, U. 2 X X X X X Frequency 3 X X X X X The HF/MF working channel number indicated by the values of the digits TM, M, H, T and U. u 8 X X X X X cC Only used for Recommendation 586 equipment. u 9 0 X X X X The VHF working channel number indicated by the values of the digits M, H, T and U. HM TM M H T u Character Character Character 2 1 ’ N ote — Character 1 is the last character transmitted. TABLE XIV — Position information (Annex I, § 8.2.2.3) Quadrant Latitude L ongitude digit N E = 0 • N W = 1 H undreds T ens o f U n its o f Tens o f U nits o f T ens o f U nits o f T ens o f U nits o f SE = 2 o f degrees degrees m inutes m inutes degrees degrees m inutes m inutes SW = 3 degrees 55 X X X X X X X X X X Character Character Character Character Character Character 6 5 4 3 2 1 N o te — Character 1 is the last character transmitted. 148 Rec. 493-4 ANNEX II EQUIPMENT CLASSES 1. Class A equipment is that which is intended to meet the IMO GMDSS carriage requirements. Class B equipment may be applicable to small ships equipped only with VHF and/or MF. Class C equipment is intended as an add-on for VHF equipment to provide DSC alerting giving ship identification only. 2. Class A — including all facilities of Annex I of this Recommendation. 3. Class B — providing minimum facilities for equipment on ships not required to use Class A equipment. This equipment should provide for: — alerting, acknowledgement and relay facilities for distress purposes; — calling and acknowledgement for general communication purposes; and — calling in connection with semi-automatic/automatic services. 3.1 Transmit capabilities 3.1.1 Format specifier: Distress call All ships call Individual station call Semi-automatic/automatic service call 3.1.2 The numerical identification of the called station (address) 3.1.3 Self-identification (automatically inserted) 3.1.4 Category: Distress Urgency Safety Routine 3.1.5 Telecommands 3.1.5.1 For distress calls Telecommand: MF: H3E or J3E VHF: F3E/G3E, simplex 3.1.5.2 For distress relay calls First telecommand: MF/VHF: distress relay Second telecommand (type of subsequent communication): MF/VHF: either the telecommand contained in the received distress alert or H3E/J3E or F3E/G3E, as appropriate 3.1.5.3 For distress acknowledgement calls _ First telecommand: MF/VHF: distress acknowledgement Second telecommand (type of subsequent communication): MF/VHF: the telecommand contained in the received distress alert Rec. 493-4 149 3.1.5.4 For all other calls First telecommand: MF: for individual station calls H3E, J3E or “test” (see Annex I § 8.4) for calls using the semi-auto matic/automatic MF-services H3E, J3E or ‘‘end of call”. VHF: for individual station calls F3E/G3E simplex or duplex; for calls using the semi-automatic/auto matic VHF-services F3E/G3E simplex or duplex or “end of call”. Second telecommand: symbol No. 126 3.1.6 Distress calls: nature of distress: undesignated. 3.1.7 Distress coordinates and time (distress calls only): as defined in Annex I. 3.1.8 Frequency, channel or ship’s position information: as defined in Annex I. 3.1.9 Selection information: (semi-automatic/automatic service). Telephone number of public telephone subscriber. 3.1.10 End of sequence character: as defined in Annex I. 3.2 Receive capabilities 3.2.1 Receive and be capable of displaying all the information in calls listed in § 3.1 plus all distress relay calls having the format specifier “geographical area calls” and all “unable to comply” calls. 3.2.2 Audible alarm upon reception of any DSC call. 4. Class C — simple add-on for existing VHF transceivers. 4.1 The capability of transmitting a distress call with fixed content in accordance with Annex I Table IV. The “nature of distress” should be “undesignated distress” (symbol No. 107), “distress coordinates” and “time” should be the digit 9 repeated ten times and the digit 8 repeated four times and the type of subsequent communication should be “F3E/G3E simplex!’ (symbol No. 100). 150 Rec. 541-3 RECOMMENDATION 541-3* OPERATIONAL PROCEDURES FOR THE USE OF DIGITAL SELECTIVE-CALLING (DSC) EQUIPMENT IN THE MARITIME MOBILE SERVICE (Question 9/8) (1978-1982-1986-1990) The CCIR, CONSIDERING ' ' ■ . (a) that provisions for digital selective-calling (DSC) have been set out in Articles 60 and 62 of the Radio Regulations; (b) Resolution No. 311 and Recommendation No. 312 of the World Administrative Radio Conference, Geneva, 1979; (c) that digital selective-calling will be used as described in Recommendation 493; (d) that the requirements of Chapter IV of the 1988 amendements to the International Convention for the Safety of Life at Sea, 1974, for the Global Maritime Distress and Safety System are based on the use of digital selective-calling for distress alerting on terrestrial frequencies and that operational procedures are necessary for transition to, and implementation of that system; (e) . that, as far as is practicable, operational procedures in all frequency bands and for all types of communications should be similar; (f) that digital selective-calling may provide a useful supplementary means of transmitting a distress call in addition to the provisions of transmitting the distress call by existing methods and procedures in the Radio Regulations; (g) that conditions when alarms have to be actuated should be specified, UNANIMOUSLY RECOMMENDS 1. that the digital selective-calling system having technical and operational characteristics in accordance with Recommendation 493 should be used in the maritime mobile service; 2. that the operational procedures to be observed in the MF, HF and VHF bands for DSC calling should be in accordance with Annex I for distress and safety calls and Annex II for other calls; 3. that provisions should be made at stations equipped for DSC for: 3.1 the manual entry of address, type of call, category and various messages into a DSC sequence; 3.2 the verification and if necessary the correction of such manually formed sequences; 3.3 a specific aural alarm and visual indication to indicate receipt of a distress or urgency call or a call having distress category. It should not be possible to disable this alarm and indication. Provisions should be made to ensure that they can be reset only manually; 3.4 aural alarm(s) and visual indication for calls other than distress and urgency. The aural alarm(s) may be capable of being disabled; 3.5 such visual indicators to indicate: 3.5.1 ' type of received call address (to all stations, to a group of stations, geographical, individual); 3.5.2 category; 3.5.3 identity of calling station; 3.5.4 numerical or alphanumerical type of information, e.g. frequency information and telecommand; 3.5.5 type of “end of sequence” character; 3.5.6 detection of errors, if any; * The Director, CCIR, is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO) and the CCITT. Rec. 541-3 151 3.6 monitoring the VHF channel used for digital selective-calling purposes to determine the presence of a signal and, except for distress and safety calls, provide facilities for automatically preventing the transmission of a DSC call until the channel is free; 4. that the equipment should be simple to operate. Note — The following definitions are used throughout this Recommendation: a) single frequency: the Siame frequency is used for transmission and reception; b) paired frequencies: frequencies which are associated in pairs; each pair consisting of one transmitting and one receiving frequency; c) international DSC frequencies:...those frequencies designated in the Radio Regulations for exclusive use for DSC on an international basis; d) national DSC frequencies: those frequencies assigned to individual coast stations or group of stations on which DSC calling is permitted (this may include working frequencies as well as calling frequencies). The use of these frequencies must be in accordance with the Radio Regulations; e) automatic DSC operation at a ship station: a mode of operation employing automatic tunable transmitters and receivers, suitable for unattended operation which provide for automatic call acknowledgements upon reception of a DSC and automatic transfer to the appropriate working frequencies; f ) call attempt: one or a limited number of call sequences directed to the same stations on one or more frequencies and within a relatively short time period (e.g. a few minutes). A call attempt is considered unsuccessful if a calling sequence contains symbol RQ at the end of the sequence and no acknowledgement is received in this time interval. ANNEX I PROVISIONS AND PROCEDURES FOR DISTRESS AND SAFETY CALLS 1. Introduction The terrestrial elements of the Global Maritime Distress and Safety System adopted by the 1988 amendments to the International Convention for the Safety of Life at Sea, 1974, are based on the use of digital selective-calling (DSC) for a distress and safety communications. 2. DSC distress call and message The DSC “distress call” provides for alerting, self-identification, ship’s position including time, nature of distress and contains both the distress call (No. 3091 and 3092) and the distress message (No. 3093 and 3094) as defined in the Radio Regulations. 3. Procedures for DSC distress calls 3.1 Transmission by a mobile unit in distress 3.1.1 The DSC equipment should be capable of being preset to transmit the distress call on at least one distress alerting frequency. 3.1.2 The distress call shall be composed in accordance with Recommendation 493; the ship’s position information, the time at which it was taken and the nature of distress should be entered as appropriate. If the position of the ship cannot be entered, then the position information signals shall be transmitted automatically as the digit 9 repeated ten times. If the time cannot be included, then the time information signals shall be transmitted automatically as the digit 8 repeated four times. 152 Rec. 541-3 3.1.3 Distress call attempt At MF and HF a distress call attempt may be transmitted as a single frequency or a multi frequency call attempt. At VHF only single frequency call attempts are used. 3.1.3.1 Single frequency call attempt A distress call attempt should be transmitted as five consecutive calls on one frequency. To avoid call collision and the loss of acknowledgements, this call attempt may be transmitted on the same frequency again after a random delay of between 3>lA and 4lA min from the beginning of the initial call. This allows acknowledgements arriving randomly to be received without being blocked by retransmission. The random delay should be generated automatically for each repeated transmission, however it should be possible to override the automatic repeat manually. At MF and HF, single frequency call attempts may be repeated on different frequencies after a random delay of between VA and 4lA min from the beginning of the initial call. However, if a station is capable of receiving acknowledgements continuously on all distress frequencies except for the transmit frequency in use, then single frequency call attempts may be repeated on different frequencies without this delay. 3.1.3.2 Multi-frequency call attempt A distress call attempt may be transmitted as up to 6 consecutive (see Note) calls dispersed over a maximum of 6 distress frequencies (1 at MF and 5 at HF). Stations transmitting multi-frequency distress call attempts should be able to receive acknowledgements continuously on all frequencies except for the transmit frequency in use, or be able to complete the call attempt within 1 min. Multi-frequency call attempts may be repeated after a random delay of between 3 lA and 4Vi min from the beginning of the previous call attempt. Note — A VHF call may be transmitted simultaneously with an MF/HF call. 3.1.4 In the case of distress the operator should: 3.1.4.1 enter the desired mode of the subsequent communication and if time permits, enter the ship’s position and time (see Note) it was taken and the nature of distress (see Note); 3.1.4.2 select the distress frequency(ies) to be used (see Note); v 3.1.4.3 activate the “distress call” attempt by a simple action. Note — If these are not provided automatically. 3.2 Reception The DSC equipment should be capable of maintaining a reliable watch on a 24-hour basis on appropriate DSC distress alerting frequencies. 3.3 Acknowledgement o f distress calls Acknowledgements of distress calls should be initiated manually. Acknowledgements should be transmitted on the same frequency as the distress call was received. 3.3.1 Acknowledgements of DSC distress calls transmitted on MF or HF should be initiated with a minimum delay of 1 min after receipt of a distress call, and normally within a maximum delay of 23A min. This allows all calls within a single frequency or multi-frequency call attempt to be completed and should allow sufficient time for coast stations to respond to the distress call. Acknowledgements on VHF should be transmitted as soon as practicable. ' 3.3.2 The acknowledgement of a distress call consists of a single DSC acknowledgement call which should be addressed to “all ships” and include the identification (see Recommendation 493) of the ship whose distress call is being acknowledged. Rec. 541-3 153 3.3.3 Distress calls should normally be acknowledged by DSC only by appropriate coast stations. Coast stations should, in addition, set watch on radiotelephony and, if the “mode of subsequent communication” signal in the received distress call indicates teleprinter, also on narrow-band direct-printing (NBDP) (see Recommendation 493). In both cases, the radiotelephone and NBDP frequencies should be those asso ciated with the frequency on which the distress call was received. 3.3.4 Ship stations should, on receipt of a distress call, set watch on an associated radiotelephone distress and safety traffic frequency and acknowledge the call by radiotelephony. If a ship station continues to receive a DSC distress call on an MF or VHF channel, a DSC acknowledgement should be transmitted to terminate the call and should inform a coast station or coast earth station by any practicable means. 3.3.5 The automatic repetition of a distress call attempt should be terminated automatically on receipt of a DSC distress acknowledgement. 3.3.6 When distress and safety traffic cannot be successfully conducted using radiotelephony, an affected station may indicate its intention (using an “all ships” DSC call, with the category distress, and normally indicating the frequency of the associated NBDP channel) to conduct subsequent communications on the associated frequency for narrow-band direct-printing telegraphy. 3.4 Distress relays 3.4.1 A distress relay call should use the telecommand signal “distress relay” in accordance with Recommendation 493 and the calling attempt should follow the procedures described in § 3.1.3 to 3.1.3.2 above for distress calls. 3.4.2 Any ship, receiving a distress call on an HF channel which is not acknowledged by a coast station within 5 min, should transmit a distress relay call to the appropriate coast station. 3.4.3 Distress relay calls transmitted by coast stations, or by ship stations addressed to “all ships”, should be acknowledged by radiotelephony. Distress relay calls transmitted by ships should be acknow ledgement by a coast station transmitting a “distress relay acknowledgement” call in accordance with the procedures for distress acknowledgements given in § 3.3 to 3.3.3. 4. Procedures for DSC urgency and safety calls (see Note) 4.1 DSC, on the distress and safety calling frequencies, should be used to advise shipping on the impending transmission of urgency, vital navigational and safety messages, except when the transmissions take place at routine times. Where the subsequent transmission of an urgency, vital navigational or safety message takes place on a working frequency, the call should indicate the frequency which will be used. 4.2 The announcement and identification of medical transports should be carried out by digital selective calling techniques, using appropriate distress and safety calling frequencies. Such calls should use the category “urgency”, and telecommand “medical transport” and be addressed to “all ships”. Note — Use of the DSC distress and safety calling frequencies for urgency and safety calls is acceptable, technically, provided that the total channel loading is maintained below 0.1 erlang. 5. Testing the equipment used for distress and safety calls Testing on the exclusive DSC distress and safety calling frequencies should be avoided as far as possible by using other methods. There should be no test transmissions on the DSC calling channel on VHF. However, when testing on the exclusive DSC distress and safety calling frequencies on MF and HF is unavoidable, it should be indicated that these are test transmissions (see provision N3068 Mob-87 of the Radio Regulations). The test call should be composed in accordance with Recommendation 493 (see Annex I, Table VI) and the call should be acknowlegded by the called coast station. Normally there would be no further communication between the two stations involved. 154 Rec. 541-3 ANNEX II PROVISIONS AND PROCEDURES FOR CALLS OTHER THAN DISTRESS AND SAFETY 1. Frequency/channels 1.1 As a rule, paired frequencies should be used at HF and MF, but in exceptional cases for national purposes, a single frequency may be used. A single frequency channel should be used at VHF. 1.2 International calling The paired frequencies listed in Appendix 31 and Article 62 should be used for international DSC calling. 1.2.1 At HF and MF international DSC frequencies should only be used for shore-to-ship calls and for the associated call acknowledgements from ships fitted for automatic DSC operation where it is known that the ships concerned are not listening to the coast station’s national frequencies. 1.2.2 All ship-to-shore DSC calling at HF and MF should be done on the coast station’s national frequencies. - 1.3 National calling Coast stations should avoid using the international DSC frequencies for calls that may be placed using national frequencies. 1.3.1 Ship stations should keep watch on appropriate national and international channels. (Appropriate measures should be taken for an even loading of national and international channels.) 1.3.2 Administrations are urged to find methods and negotiate terms to improve the utilization of the DSC channels available, e.g.: — coordinated and/or joint use of coast station transmitters; — optimizing the probability of successful calls by providing information to ships on suitable frequencies (channels) to be watched and by information from ships to a selected number of coast stations on the channels watched on-board. 2. Operating procedures A typical DSC calling and acknowledgement sequence contains the following signals (see Recommenda tion 493). Composition o f a typical DSC calling and acknowledgement sequence Signal Method o f composition — format specifier selected — address entered — category selected — self-identification pre-programmed — telecommand, information , selected — frequency information (if appropriate) entered — telephone number (semi-automatic/auto- matic ship-to-shore connections only) entered — end of sequence signal selected (see Note) Note — If the calling sequence EOS signal incorporates a request for acknowledgement “RQ” (117) an acknowledgement is mandatory and shall incorporate the EOS signal “BQ” (122). The method of composing a DSC sequence is illustrated in the flow diagram of Fig. 5. Rec. 541-3 155 2.1 Coast station initiates call to ship o Figures 1 and 2 illustrate the procedures below in flow chart and by time sequence diagram respectively. 2.1.1 There are two categories of calls for commercial communications: — routine call; , — ship’s business call (see Recommendation 493, Annex I, § 6.4.1).' 2.1.2 If a direct connection exists between the calling subscriber and the coast station, the coast station asks the calling subscriber for the approximate position of ship. 2.1.3 If the ship’s position cannot be indicated by the caller, the coast station operator tries to find the location in the information available at the coast station. 2.1.4 The coast station checks to see whether the call would be more appropriate through another coast station (see § 1.3.2). 2.1.5 The coast station checks to see whether transmission of a digital selective call is inappropriate or restricted (e.g. ship not fitted with DSC or barred). 2.1.6 Assuming a DSC is appropriate the coast station composes the calling sequence as follows: — selects format specifier; — enters address of the ship; x — selects category; — selects telecommand information; — inserts working frequency information in the message part of the sequence, if appropriate; — usually selects “end of sequence” signal “RQ”. However, if the coast station knows that the ship station cannot respond or the call is to a group of ships the frequency is omitted and the end of sequence signal should be 127, in which case the following procedures (§2.1.13 to 2.1.15) relating to an acknowledgement are not applicable. 2.1.7 The coast station verifies the calling sequence. 2.1.8 The coast station operator chooses the calling frequencies which are most suitable for the ship’s location. 2.1.8.1 After checking as far as possible that there are no calls in progress, the coast station operator initiates the transmission of the sequence on one of the frequencies chosen. Transmission on any one frequency should be limited to no more than 2 call sequences separated by intervals of at least 45 s to allow for reception of an acknowledgement from the ship, or exceptionally (see Recommendation 493) to one “call attempt” consisting of up to five transmissions. 2.1.8.2 If appropriate, a “call attempt” may be transmitted, which may include the transmission of the same call sequence on other frequencies (if necessary with a change of working frequency information to correspond to the same band as the calling frequency) made in turn at intervals of not less than 5 min, following the same pattern as in § 2.1.8.1. 2.1.9 If an acknowledgement is received further transmission of the call sequence should not take place. 2.1.10 The acknowledgement of the received call should only be transmitted upon receipt of a calling sequence which terminates with an acknowledgement request. 2.1.11 When a station called does not reply, the call attempt should not normally be repeated until after an interval of at least 30 min. The same call attempt should not be repeated more than five times every 24 h. The aggregate of the times for which frequencies are occupied in one call attempt, should normally not exceed one minute. The following procedures apply at the ship: 2.1.12 Upon receipt of a calling sequence at the ship station, the received message is recorded and an appropriate indication is activated as to whether the call category is “routine” or “ship’s business”. The -category does not affect the DSC procedures at the ship. 2.1.13 When a received call sequence contains an end of sequence signal RQ, an acknowledgement sequence should be composed and transmitted in accordance with § 2. The format specifier and category information should be identical to that in the received calling sequence. 156 Rec. 541-3 2.1.13.1 If the ship station is not equipped for automatic DSC operation, the ship’s operator initiates an acknowledgement to the coast station after a delay of at least 5 s but no later than 4lA min of receiving the calling sequence, using the ship-to-shore calling procedures detailed in § 2.2. However the transmitted sequence should contain a “BQ” end of sequence signal in place of the “RQ” signal. If such an acknowledgement cannot be transmitted within 5 min of receiving the calling sequence then the ship station should instead transmit a calling sequence to the coast station using the ship-to-shore calling procedure detailed in § 2.2. 2.1.13.2 If the ship is equipped for automatic DSC operation, the ship station automatically transmits an acknowledgement with an end of sequence signal “BQ”. The start of the transmission of this acknowledge ment sequence should be within 30 s for HF and MF or within 3 s for VHF after the reception of the complete call sequence. 2.1.13.3 If the ship is able to comply immediately the acknowledgement sequence should include a telecommand signal which is identical to that received in the calling sequence indicating that it is able to comply. 2.1.13.4 If the ship is not able to comply immediately the acknowledgement sequence should include the telecommand signal 104 (unable to comply), with a second telecommand signal giving additional informa tion (see Recommendation 493). At some later time when the ship is able to accept the traffic being offered, the ship’s operator initiates a call to the coast station using the ship-to-shore calling procedures detailed in § 2.2. 2.1.14 If a call is acknowledged indicating ability to comply immediately and communication between coast station and ship station on the working channel agreed is established, the DSC call procedure is considered to be completed. 2.1.15 If the ship station transmits an acknowledgement which is not received by the coast station then this will result in the coast station repeating the call (in accordance with § 2.1.11). In this event the ship station should transmit a new acknowledgement. If no repeated call is received the ship station should transmit an acknowledgement or calling sequence in accordance with § 2.1.13.1. 2.2 Ship station initiates call to coast station * Figures 3 and 4 illustrate the procedures below in flow chart and by time sequence diagram respectively. This procedure should also be followed both as a delayed response to a call received earlier from the coast station (see §2.1.13.1) and to initiate traffic from the ship station. 2.2.1 The ship composes the calling sequence as follows: — selects the format specifier; — enters address; — selects the category; — selects the telecommand information; — inserts working frequency information in the message part of the sequence if appropriate; — inserts telephone number required (semi-automatic/automatic connections only); — selects the “end of sequence” signal RQ. 2.2.2 The ship verifies the calling sequence. 2.2.3 The ship selects the most appropriate calling frequency. 2.2.4 The ship initiates the transmission of the sequence on the frequency selected after checking as far as possible that there are no calls in progress on that frequency. * See Recommendation 689 and Report . 1161 for further details of procedures applicable only to the semi-automatic/auto matic services. Rec. 541-3 157 2.2.5 If a called station does not reply, the call sequence from the ship station should not normally be repeated until after an interval of at least 5 min for manual connections, or 5 s or 25 s in the case of semi-automatic/automatic VHF or MF/HF connections respectively. These repetitions may be made on alternative frequencies if appropriate. Any subsequent repetitions to the same coast station should not be made until at least 15 min have elapsed. 2.2.6 The coast station should transmit an acknowledgement sequence (after checking as far as possible that there are no calls in progress on the frequency selected), after a delay of at least 5 s but not later than 4/2 min for manual connections, or, within 3 s for semi-automatic/automatic connections, containing the format specifier, the address of the ship, the category, the coast station self-identification and: — if able to comply immediately on the working frequency suggested, the same telecommand and frequency information as in the call request; . - if no working frequency was suggested by the ship station then the acknowledgement sequence should include a channel/frequency proposal; — if not able to comply on the working frequency suggested but able to comply immediately on an alternative frequency, the same telecommand but an alternative working frequency; — if unable to comply immediately the telecommand signal 104 with a second telecommand signal giving additional information. For manual connections only, this second telecommand signal may include a queue indication. < The end of sequence signal BQ should also be included. 2.2.7 For manual connections, if a working frequency is proposed in accordance with § 2.2.6 but this is not acceptable to the ship station, then the ship station should immediately transmit a call to the coast station indicating (by the use of telecommand signals 104 and 108) that it cannot comply on that frequency. 2.2.7.1 The coast station should then transmit an acknowledgement in accordance with § 2.2.6 either accepting the ship station’s original suggested frequency or proposing a second alternative. 2.2.8 On receipt of an acknowledgement which indicates ability to comply the DSC procedures are complete and both coast station and ship station should communicate on the working frequencies agreed with no further exchange of DSC calls. 2.2.9 If the coast station transmits an acknowledgement which is not received at the ship station then the ship station should repeat the call in accordance with § 2.2.5. Rec. 541-3 FIGURE 1 - Flow chart o f operational procedures for calling in the shore-to-ship direction Rec. 541-3 159 Ship Working Coast station station frequencies TX RX RX TX f1 f1’ Contact on working frequencies _ F> A (s), c, 1(c), T l. T2. fl R n t1 — — t4 c M r.lC.lW .THlOa------tl - T2, t l , BQ t 2 tl t 5 F’ A(s)> c > 1(c), T l, T2. f l Rn Contact on ti - working frequencies ts - b) Automated transmitter (unable to comply) F> A'(s), c, 1(c), Tl, T2. f 1 R n F AfrVc'.lW ,Tl,T2tfltRQ. ------ ------i_ A ( s ) , C. IfcV T i T2 (103), fl, BQ Contact on working frequencies c) Ship transmitter not automated. Ship makes a delayed (> 5 min) response to coast station and encounters queue on working frequency FIGURE 2 - Examples o f timing diagrams for calling in shore-to-ship direction (See legend in Fig. 4) , 160 Rec. 541-3 FIGURE 3 - Flow chart o f operational procedures for calling in the ship-to-share direction Rec. 541-3 161 Ship Working Coast station station frequencies TX RX RX TX f1 f r tl — v Aid. C. I(s), T l, T2, fURQJ ts F>a ( s).C ,1 ( c).T 1 .T 7 | q Rn tl Contact on —- working t3 frequencies a) Able to comply immediately ti _ F Afc). C, I(s), T l, T2, fl, RQ ts — - tl — —’ A(s)’ c > Kc). Tl (104) Contact on t 3 — 12 (103), fl, BQ working frequencies - b) Queue exists on working frequency FIGURE 4 - Examples o f timing diagrams for calling in ship-to-shore direction The following symbols are used in Figs. 2 and 4: t, : transmission time of a DSC sequence t2 : interval between the DSC reception at the ship and transmission from the ship after the operator’s appearance in the radio room (from several minutes up to several hours) t3 : transition time from calling to working frequency including, if necessary, the time for working channel clearing (queue waiting time) t4 : as defined in § 2.1.13.2 ts i : time for coast station to prepare acknowledgement (see § 2.2,6) F : format specifier A : called station address I : calling station J suffix (c) or (s) indicate coast station self-identification I or ship station respectively C : category Tl : first telecommand signal, (104) indicates unable to comply T2 : second telecommand signal, (103) indicates queue fl, fl' : working frequencies RQ, BQ : end of sequence signals 162 Rec. 541-3 Acknowledgement 2.1.13 (Ship) 2.2.6 (Coast) 2.1.6 (Coast) 2.2.1 (Ship) >) S e le c t telecommand information FIGURE 5 - Composition procedures for calling and acknowledgement sequences (for calls other than distress and safety) 0 ) Normally. Ack. RQ m ay autom atically be selected as an EOS signal of a calling sequence to an individual station. (2) The form at specifier and the category are autom atically transferred from the received call. The self-ID in the received sequence is autom atically transferred into the address part of acknowledgem ent sequence by selecting Ack. BQ. (3) The frequency inform ation is autom atically transferred from the received call. (4) This procedure is only for coast stations. (s) When able to com ply, and no queue exists, then the telecom m and inform ation is autom atically transferred from the received call. Rec. 626 163 RECOMMENDATION 626 EVALUATION OF THE QUALITY OF DIGITAL CHANNELS IN THE MARITIME MOBILE SERVICE (Question 42/8) (1986) The CCIR, CONSIDERING (a) that the administrations of numerous countries are developing different types of equipment for the transmission of digital information on radio channels of the maritime mobile service ; (b) that specific technical Recommendations should be adopted on the basis of a comparative analysis of the overall final results of laboratory or field tests performed on the equipment offered by various administrations; (c) that, however, it is generally difficult to carry out joint tests on different types of equipment; (d) that owing to the variations in the probabilistic characteristics of radio channels in the maritime mobile service, the conditions of the various tests may differ considerably, which may make it difficult to provide a basis of comparison for the evaluation of the final results; (e) that equipment performance is seriously affected by inadequate radiocommunication conditions, CONSIDERING FURTHER: (f) the need to provide a standard method for the evaluation of the conditions and final results of tests conducted on equipment used in digital radio channels of the maritime mobile service, UNANIMOUSLY RECOMMENDS 1. that the main parameter adopted to characterize the effectiveness of equipment proposed by administra tions for use in digital maritime radio channels should be the gain in channel quality, relative to a reference system operated just before the start of each test; Note. — The reference system consists of a standard character generator, e.g. a pseudo-random generator connected to a modulator of the same type as used in the equipment to be tested, or a CCITT standard modem for the data speed to be tested where applicable. 2. that the most practical method of assessing the quality of such channels is based on the statistical (probabilistic) characteristics (parameters) obtained (or calculated) before and during the operation of the new equipment. These parameters may be applied for the comparative evaluation of different equipment without any joint tests; 3. that the main parameter adopted to characterize initial channel quality (before the operation of the equipment), i.e. the test conditions, should be the value of the character error probability. For test purposes, the range of variation in this value during the experiment may be from 10_1to l0 ~ 4; 4. that the duration of a single test period (session) should, as a rule, be 10 to 12 min; 5. that the number of test periods sufficient for the statistical (probabilistic) evaluation of the final results should be in the range from 100 to 150; 6. that the main parameter adopted to characterize channel quality during operation of the equipment should also be the character error probability; 7. that the mean character error probability obtained (or calculated) should, as a rule, be represented as its integral distribution; 8. that other indicators characterizing channel quality in the use of the equipment should be as follows; — mean link setting-up time; — operational information processing rate (mean information transmission rate); 9. that in principle, the difference between the final and initial character error probabilities should define the effectiveness of the equipment. However, for the analysis of performance to be complete, account must also be taken of the additional indicators given under § 8 of this Recommendation, as well as of the technical characteristics (power, selectivity, antenna losses, etc.) of other radiotechnical plant and systems contributing to the formation of the digital radio channel. 164 Rec. 627 RECOMMENDATION 627 TECHNICAL CHARACTERISTICS FOR HF MARITIME RADIO EQUIPMENT USING NARROW-BAND PHASE-SHIFT KEYING (NBPSK) TELEGRAPHY (Question 54/8) (1986) The CCIR, . CONSIDERING (a) the fact that direct printing communication modes are currently being widely introduced in the maritime mobile service; (b) that the frequency stability of ship radio receivers and transmitters has considerably improved; (c) that synchronous 7-unit signal codes with error detection are widely used in direct-printing links; (d) that the load on direct-printing channels in the HF maritime mobile service has increased; (e) that NBPSK signals are received with better noise immunity than FSK signals at the same transmitter power; - (f) that the use of NBPSK telegraphy allows two PSK channels to be accommodated in one standard channel of narrow-band telegraphy in the maritime mobile service at a modulation rate in each channel of 100 Bd or one PSK channel at a modulation rate of 200 Bd; (g) that the level of mutual channel interference in PSK mode does not exceed that of FSK mode; UNANIMOUSLY RECOMMENDS that when NBPSK telegraphy equipment is used in the HF maritime mobile service, the equipment characteristics should meet the requirements indicated in Annex I. ANNEX I 1. The modulation rate on the radio link should be i00 or 200 Bd. 2. The carrier wave phase modulation rule should be the following: Tn the transmission of signal element Y, the carrier wave phase changes by 180° relative to the phase of the preceding bit: but in the transmission of signal element B, the carrier wave phase remains the same as for the preceding bit. Note. — Signal elements B and Y are defined in Recommendations 625 and 490. 3. The deviation of the information sequence transmission rate from the nominal value must not exceed ± 0.01 bit/s. 4. The necessary transmission bandwidth should be: 4.1 not more than 110 Hz for a rate of 100 Bd; 4.2 not more than 210 Hz for a rate of 200 Bd. 5. The reduction of the mean transmitter output power at the maximum modulation rate compared with that of the unmodulated carrier should not exceed 4 dB. 6. The levels of the out-of-band emission at the transmitter output at a modulation rate of 100 Bdshould be: 6.1 —30 dB referred to unmodulated carrier for a bandwidth of not more than 260 Hz; 6.2 —40 dB referred to unmodulated carrier for a bandwidth of not more than 500 Hz; 6.3 —50 dB referred to unmodulated carrier for a bandwidth of not more than 700 Hz; 6.4 — 60 dB referred to unmodulated carrier for a bandwidth of not more than 900 Hz; Rec. 627 165 7. The levels of the out-of-band emission at the transmitter output at a modulation rate of 200 Bd should be: 7.1 —30 dB referred to unmodulated carrier for a bandwidth of not more than 520 Hz; 7.2 —40 dB referred to unmodulated carrier for a bandwidth of not more than 1000 Hz; 7.3 -50 dB referred to unmodulated carrier for a bandwidth of not more than 1400 Hz; 7.4 — 60 dB referred to unmodulated carrier for a bandwidth of not more than 1800 Hz. 8. The standard maritime mobile service narrow-band telegraphy channel may accommodate two PSK sub-channels at a maximum modulation rate of 100 Bd in each PSK sub-channel. The frequency of one PSK sub-channel should be 130 Hz lower than the assigned frequency of a standard narrow-band telegraphy channel, and the frequency of the second sub-channel should be 130 Hz higher than the assigned frequency. 9. The transmitter should use class of emission GIB or single-sideband classes J2B or J7B. 10. If class J2B is used, the frequency of the sub-carrier signal to the audio frequency input of the transmitter should be 1570, 1700 or 1830 Hz, while the frequency tolerance of the sub-carrier from the nominal value should not exceed ± 0.5 Hz. 11. If class J7B is used, the frequencies of the sub-carrier signals to the audio frequency input of the transmitter must be 1570 and 1830 Hz, while the tolerance of the sub-carrier frequency from the nominal value should not exceed ± 0.5 Hz. 12. The maximum transmitter frequency tolerance from the nominal value should not exceed ± 5 Hz. 13. The linearity of the amplitude characteristics of the transmitter information signal amplification channel should be such that the level of intermodulation components does not exceed —31 dB for the third order, —38 dB for the fifth order, and —43 dB for the seventh order. 14. The maximum frequency tolerance of the receiver tuning from the nominal value should not exceed ± 5 Hz. PAGE INTENTIONALLY LEFT BLANK PAGE LAISSEE EN BLANC INTENTIONNELLEMENT Rec. 219-1 167 SECTION 8C: MARITIME MOBILE SERVICE; TELEPHONY AND RELATED SUBJECTS RECOMMENDATION 219-1 ALARM SIGNAL FOR USE ON THE MARITIME RADIOTELEPHONY DISTRESS FREQUENCY OF 2182 kHz (1951-1953-1956-1966) The CCIR, CONSIDERING (a) that it is desirable and practicable to establish an internationally agreed alarm signal for use on the calling and distress frequency of 2182 kHz (see Art. 39 of the Radio Regulations); (b) that the alarm signal should be such as to : — provide reliable operation of automatic alarm equipment; — provide a distinctive signal, which is readily recognized aurally, when received on a loudspeaker or headphones; — be capable of being received through interference from speech transmissions, through other kinds of interference, and through noise; — avoid false responses when received either aurally or by automatic means; — be capable of being produced by a simple manual device, as well as by automatic means; (c) that the alarm signal should be such as to permit the construction of alarm equipment which is rugged, dependable, stable in performance, of low cost, of easy production, of long life with a minimum of maintenance, and which can be used with existing maritime radiotelephone equipment; (d) that to help in clearing the calling and distress frequency channel of emissions from other stations the alarm signal and detecting device should be effective beyond the range at which speech transmission is satisfactory; (e) that the automatic alarm equipment should be capable of operating, in as short a time as possible, consistent with the avoidance of false responses; (f) that the results of the further examination of this problem by the administrations which participated in Study Programme 29, Geneva, 1951, are sufficiently conclusive to determine the essential characteristics of the signal, including tolerances that should be recommended for international adoption; (g) that it is possible to specify the minimum performance standards for automatic alarm equipment, for both transmission and reception, to such an extent that future progress and development are not hampered; (h) that it is undesirable that the specification of performance standards for automatic alarm equipment should exceed in scope the requirements already established by international agreement for automatic alarm devices, intended for the reception of the international alarm signal or the international distress signal in radiotelegraphy, normally transmitted on the frequency 500 kHz (see Nos. 3281 and 3282, and Appendix 36, § 1 of the Radio Regulations; and Chapter IV, Regulation 11 of the International Convention for the Safety of Life at Sea, London, 1974), UNANIMOUSLY RECOMMENDS 1. that the alarm signal described below should be adopted internationally, for use on the maritime radiotelephony calling and distress frequency of 2182 kHz; 1.1 the alarm signal shall consist of two substantially sinusoidal audio-frequency tones, transmitted alternately. One tone shall have a frequency of 2200 Hz and the other a frequency of 1300 Hz. The duration of each tone shall be 250 ms; 1.2 the tolerance of the frequency of each tone shall be ± 1.5%; the tolerance on the duration of each tone shall be ± 50 ms; the interval between successive tones shall not exceed 50 ms; the ratio of the amplitude of the stronger tone to that of the weaker shall be within the range 1 to 1.2; 1.3 when generated by automatic means, the alarm signal shall be sent continuously for a period of at least 30 s but not exceeding one minute; when generated by other means, the signal shall be sent as continuously as is practicable over a period of approximately one minute; 168 Rec. 219-1 2. that the automatic devices, intended for the reception of the alarm signal in question, should fulfil the following conditions: 2.1 the frequencies of maximum response of the tuned circuits, and other tone selecting devices, shall be subject to a tolerance of ± 1.5% in each instance; and the response shall not fall below 50% of the maximum response for frequencies within 3% of the frequency of maximum response; 2.2 in the absence of noise and interference, the automatic receiving equipment shall be capable of operating from the alarm signal in a period of not less than four and not more than six seconds; 2.3' the automatic receiving equipment shall respond to the alarm signal, under conditions of intermittent interference caused by atmospheric and powerful signals other than the alarm signal, preferably without any manual adjustment being required during any period of watch maintained by the equipment; 2.4 the equipment shall not be actuated by atmospheric or by strong signals other than the alarm signal; 3. that the automatic alarm equipment for both transmission and reception, on the calling and distress frequency of 2182 kHz, shall fulfil the following conditions: 3.1 the equipment shall be effective beyond the range at which speech transmission is satisfactory; ■ ! 3.2 the equipment shall be capable of withstanding vibration, humidity, changes of temperature and variations in power supply voltage equivalent to the severe conditions experienced on board ships at sea, and shall continue to operate under such conditions; 3.3 the equipment should, as far as practicable, give warning of faults that would prevent the apparatus from performing its normal functions during watch hours; t ' 4. that, before any type of automatic alarm equipment for transmission and reception oh the calling and distress frequency of 2182 kHz is approved for use on ships, the administrations having jurisdiction over those ships should be satisfied by practical tests, made under operating conditions equivalent to those obtained in practice, that the equipment complies with the provisions of § 1,2 and 3 of this Recommendation. Rec. 257-2 169 RECOMMENDATION 257-2 SELECTIVE-CALLING SYSTEM FOR USE IN THE MARITIME MOBILE SERVICE (1959-1970-1978) The CCIR, CONSIDERING (a) that selective calling of ships by coast stations would expedite the handling of traffic in the maritime mobile service; (b) that a selective-calling system has the following advantages: — it is rapid and positive; — it overcomes the disadvantages of ships having to listen to all calls; — it reduces the difficulties caused by differences of language; — it reduces the time taken by coast stations to establish contact with ships and thus reduces congestion on the channels used for calling; — it increases operating efficiency generally; (c) that a number of administrations have an immediate requirement for selective-calling facilities; -(d) that ideally, a selective-calling system should be suitable for use in all maritime mobile bands; (e) that a selective-calling system should have sufficient capacity of code numbers to accommodate all ships that desire to use it; , (f) that the International Maritime Organization (IMO) has expressed in its letter of 2 November, 1966, the opinion that it would be desirable from the viewpoint of maritime safety, if selective-calling devices could include a facility for calling all ships; (g) that there may be a need for a facility to call predetermined groups of ships; (h) that it may be operationally desirable for a ship’s operator to be able to ascertain either the identity of the coast station which has called him, or the VHF channel on which he should reply; (j) that a selective-calling system should be suitable for use with normal types of radio equipment on ships, UNANIMOUSLY RECOMMENDS 1. that, where there is a need to fulfil immediate requirements for selective calling, the system to be used should have the following characteristics; 1.1 the selective call signal should consist of five figures representing the code number assigned to a ship for selective calling; 1.2 the audio-frequency signal applied to the input of the coast station transmitter should consist of consecutive audio-frequency pulses conforming to the following: , 1.2.1 the audio frequencies used to identify the figures of the code number assigned to a ship should conform to the following series: TABLE I Figure Figure 1 2 3 4 5 6 7 8 9 0 repetition Audio frequency (Hz) 1124 1197 1275 1358 1446 1540 1640 1747 1860 1981 2110 For example, the series of audio-frequency pulses corresponding to the selective call 12133 would be 1124-1197-1124-1275-2110 Hz, and the series corresponding to the code number 22222 would be 1197-2110-1197-2110-1197 Hz: 170 Rec. 257-2 1.2.2 if the series of numbers represented by the use of only two frequencies, chosen from those in § 1.2.1, are reserved for calling predetermined groups of ships, then 100 different groups of numbers are available for allocation, according to the needs of administrations; 1.2.3 the waveforms of the audio-frequency generators should be substantially sinusoidal, not exceeding 2% total harmonic distortion; 1.2.4 the audio-frequency pulses should be transmitted sequentially; 1.2.5 the difference between the maximum amplitude of any audio-frequency pulses should not exceed 1 dB; 1.2.6 the duration of each audio-frequency pulse, measured between the half-amplitude points, should be 100 ms ± 10 ms; 1.2.7 the time interval between consecutive pulses, measured between the half-amplitude points, should be 3 ms ± 2 ms; 1.2.8 the rise and the decay time of each audio-frequency pulse, measured between the 10% and 90% amplitude points, should be 1.5 ms ± 1 ms; 1.2.9 the frequency tolerance of the audio frequencies given in § 1.2.1 should be ± 4 Hz; 1.2.10 the selective call signal (ship’s code number) should be transmitted twice with an interval of 900 ms ± 100 ms between the end of the first signal and the beginning of the second signal (Fig. 1); 1.2.11 the interval between calls from a coast station to different ships should be at least 1 s (Fig. 1); but the interval between calls to the same ship, or the same group of ships, should be at least 5 s; Acoustic or optical call Acoustic or optical call signal energized if correctly signal energized if correctly received at ship A received at ship B 500 ms 900 ms 500 ms > 1 0 0 0 ms 500 ms etc. 1 1 1 1 1 1 1 1 1 1 1 1 Code Interval Repetition Interval between Code number of o f code calls to different number of ship A number of ships ship B ship A FIGURE 1 - Composition of selective call signals without additional information 2. that if additional information is added to the selective call signal it should be as follows: 2.1 to identify the calling coast station four figures should be transmitted; 2.2 to identify the VHF channel on which a reply is required two “zeros” followed by two “figures” should be transmitted; 2.3 the characteristics of the signals should conform to § 1.2.1 and 1.2.3 to 1.2.9 inclusive; 2.4 the composition of the signal should be as shown in the diagram (Fig. 2), the tolerance on the 350 ms interval being ± 30 ms; Rec. 257-2 171 Acoustic or optical call Coast station identification Acoustic or optical call signal energized if correctly displayed or recorded if signal energized if correctly received at ship A correctly received at ship A received at ship B t 1000 ms 500 ms 350 ms 400 ms 350 ms 500 ms 350 ms ■ 400 ms ^ 1000 ms 500 ms <■■ — »-etc. 1 I 1 1 1 1 1 1 1 1 1 1 1 1 M i l Code Interval Addi Interval Repetition Interval Repeti Interval between Code number of tional of code tion of calls to different number of ship A informa number of addi ships ship B tion ship A tional informa tion FIGURE 2 - Composition of selective call signals with additional information 3. that an “all ships call” to actuate the receiving selectors on all ships, regardless of their individual code numbers, should consist of a continuous sequential transmission of the eleven audio frequencies given in § 1.2.1. The parameters of the audio-frequency pulses should be in accordance with § 1.2.3, 1.2.4, 1.2.5 and 1.2.9. The duration of each audio-frequency pulse, measured between the half-amplitude points, should be 17 ms ± 1 ms and the interval between consecutive pulses, measured between half-amplitude points, should not exceed 1 ms (Fig. 3). The total duration of this “all ships call” signal should be at least 5 s; > 5s 20 0 ms 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 110|11 1|2|3|4|5|6|7|8| | 8 | 9 |10|11| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |1 0 |l l FIGURE 3 - Composition of the “all ships call” signal 4. that receiving selectors on ships should operate reliably in any radio conditions acceptable for satisfactory communication; 5. that the receiving selector should be designed to accept the signals as defined in § 1 and 3. However, bearing in mind that coast stations may transmit additional signals (e.g. coast station identification), it is important to ensure that during reception of a selective call the decoder should be re-set after 250 ± 40 ms if an incorrect digit or no digit is received; 172 Rec. 257-2 6. that the receiving selector should be so designed, constructed and maintained that it is resistant to atmospherics and other unwanted signals including selective-calling signals other than that for which the decoder has been set up; 7. that the receiving selector should include an audible or visual means of indicating the receipt of a call and, if required, an additional facility allowing the determination of the identity of the calling station or the VHF channel on which to reply according to the needs of administrations ; 8. in order to distinguish whether an incoming call is a normal selective call or an “all ships call”, the multiple actuation of the ship’s decoder by the “all ships call” signal (see § 3) can be used; 9. that the indicating means mentioned in § 7 should be actuated on correct reception of the calling signal, no matter whether the correct registration has occurred on the first, or the second, or both parts of the calling signal transmitted by the coast stations; 10. that the indicating means should remain actuated until re-set manually ; 11. that the receiving selector equipment should be as simple as is practicable, be capable of reliable operation over long periods with a minimum of maintenance, and could, with advantage, include facilities for self-testing. Note. — The Director, CCIR, is requested to bring the contents of this Recommendation to the attention of IMO. Rec. 428-3 173 RECOMMENDATION 428-3* DIRECTION-FINDING AND/OR HOMING** IN THE 2 MHz BAND ON BOARD SHIPS (1963-1966-1970-1990) The CCIR, CONSIDERING (a) that Regulation IV/7.3 of the 1988 Amendments to the International Convention for the Safety of Life at Sea, 1974, requires that until 1 February 1999 every passenger ship and cargo ship of 300 tons gross tonnage and upwards shall, unless the ship is engaged in sea area A1 only, be fitted with a device for generating the radiotelephone alarm signal on the frequency 2182 kHz; (b) that Regulation V/12(p) of the International Convention for the Safety of Life at Sea, 1974, requires that when engaged on international voyages, ships of 1600. tons gross tonnage and upwards shall be fitted with a radio direction-finding apparatus, and IMO Resolution A.223(VII) prescribes that such equipment should be capable of receiving signals in the frequency range 2167 kHz to 2197 kHz; (c) that Regulation V/10 of the International Convention for the Safety of Life at Sea, 1974, requires the master of a ship at sea on receiving a distress signal to proceed with all speed to the assistance of the persons in distress; n (d) that a large number of ships of more than 1600 tons gross tonnage (which are compulsorily fitted with medium frequency radiotelegraph equipment) are voluntarily fitted with medium frequency radiotelephone equipment and that the number of such ships is increasing; (e) that the majority of deep-sea fishing vessels are fitted voluntarily with medium frequency radiotelephone equipment; (f) that an increasing number of ships are being fitted with direction-finding equipment capable of taking bearings in the 2 MHz band; (g) that direction-finding and especially homing by ships is important in cases of distress; (h) that technical studies in several countries have shown: h.a that direction-finding, or at least homing, is usually possible in the 2 MHz band on many ships; h.b that compared with the problems of direction-finding by ships in the lower parts of the medium frequency band, the main cause of error in direction-finding in the 2 MHz band is re-radiation from various parts of the ship’s superstructures, masts, downleads, halyards, stays, derricks, etc., and from other antennas; h.c that errors caused by re-radiation effects, however, should be constant if the disposition and electrical conditions of the re-radiators are constant and that such errors can be taken into account by calibrating the direction-finder; h.d that direction-finding and homing is easier on board small ships than on larger ones, because an increase in the size of ships and their superstructures, masts, etc., as given in § h.b leads to an increase of disturbing resonance effects; h.e that a reliable direction-finder calibration can be more readily obtained if it is restricted to a specific frequency such as 2182 kHz, instead of a wide frequency band; h.f that even where omnidirectional direction-finding, even on a specific frequency, is difficult or impossible (such as on board large vessels with strong re-radiation effects), homing will nearly always be possible, * The Director CCIR is invited to bring this Recommendation to the attention of IMO. ** For the purpose of this Recommendation “homing” means the taking of direction-finding bearings without ambiguity of sense within an arc of 30° on either side of the bow. 174 Rec. 428-3 UNANIMOUSLY RECOMMENDS 1. that the following technical measures and precautions should be observed when installing direction-finders for taking bearings in the 2 MHz band, and in particular for homing on the frequency 2182 kHz: 1.1 the antenna system, including the sense antenna, of the direction-finder should be erected as far as possible away from any re-radiators; ' 1.2 the direction-finder antenna system should, preferably, be installed on the fore-and-aft line of the ship; 1.3 if the direction-finding antenna system is to be fitted on a mast it should preferably be installed symmetrically on top of the mast and not to one side of it; where a mast-head installation may require the use of longer cables, their possible influence on the bearing should be taken into consideration; 1.4 the mounting of the direction-finding antenna system may be considered satisfactory for homing purposes if the calibration in the sector ahead as in § 2.5 has proved to be possible; 1.5 if the resonance frequency of a mast and its rigging is within approximately ± 20% of the frequency used for direction-finding, then the antenna system of the direction-finder should not in general be mounted on or near the top of the mast, unless the antenna system is one which is not influenced by the mast resonance. The calculation or assessment of the resonance frequency should take into account the effect of the antenna system of the direction-finder; 1.6 that the sense antenna should be mounted on or as near as is practicable to the central axis of the antenna system of the direction-finder; 1.7 the effects caused by re-radiating antenna wires can be minimized by providing properly located isolating switches for the antennas; , 1.8 re-radiation from the rigging (e.g. stays, wire ropes, etc.) should be reduced by the insertion of insulators such that the resonance frequency of the longest portion is considerably above the highest frequency used for direction-finding or considerably above 2182 kHz where the installation is used for homing only; 1.9 the formation of “closed loops”, e.g. by the rigging, should be avoided by inserting insulators at appropriate points; 1.10 to avoid electrically doubtful connections, the connecting points of movable parts of the rigging and connections between masts and derricks, wire ropes, etc., should be short-circuited as far as possible; 2. that the following measures and precautions should be observed in the calibration of direction-finders for the 2 MHz band and in particular for homing on the frequency 2182 kHz; 2.1 the rigging, downleads, derricks, halyards, etc. should be in their sea-going positions; 2.2 any antennas that affect the direction-finder should preferably be isolated and other antennas which cannot be isolated (for example, because of operational requirements), should be in the same condition as they will be when bearings are being taken or when homing is being done at sea; the condition and electrical arrangement of all antennas should be noted on the direction-finder calibration charts; 2.3 calibration in the forward direction for the purpose of homing (or a more complete calibration if so desired) should be carried out in an area well clear of the shore and of other ships. If a shore-based transmitter is used, calibration should be carried out on a line passing through that station and crossing the coast-line approximately at right angles. The transmitting antenna should radiate vertically polarized waves from a single element, and care should be taken to avoid re-radiation from any object in the vicinity. The distance between the transmitting antenna and the direction-finder should be great enough to avoid the calibration being affected by the induction field of the transmitting antenna; 2.4 , care should be taken to ensure that the direction-finder gives the correct sense on all bearings and frequencies concerned and in particular for homing purposes on the frequency 2182 kHz, within a sector of 30° on both sides of the bow; 2.5 the calibration, if not complete, should at least cover a sector of 30° on both sides of the bow, and as far as possible should be made at sufficiently small bearing intervals (say, in steps of a few degrees) to detect any sudden changes (for example, re-entrant portions where two or more different corrections exist for the same indicated bearing); 2.6 calibration at 2182 kHz should be carried out at a frequency as near as possible to 2182 kHz, special attention being paid to No. 3023 of the Radio Regulations, and to the avoidance of interference to established operations in adjacent channels; Rec. 428-3 175 3. that the calibration should be checked periodically, especially if the condition of the rigging, etc. has been altered since the last calibration; 4. that on board ships equipped with a direction-finder, the frequency range of which includes the 2 MHz band, a calibration should be made to determine if the direction-finder could be used without modification for omnidirectional direction-finding, or at least for homing on the frequency 2182 kHz; 5. that when administrations encourage the use of direction-finders on board ship, capable of operating in the 2 MHz band, or at least on the international radiotelephony distress and calling frequency 2182 kHz, they should also encourage the provision of suitable facilities for the calibration of such direction-finder equipment; 6. that administrations should bring the above Recommendation to the attention of those responsible for the provision, installation and maintenance of direction-finders on ships. ANNEX I Under good conditions, when the above precautions and technical measures have been taken, an accuracy of about ± 2° can be attained in taking bearings in the 2 MHz band by reception of “ground” waves on board ships of less than about 800 tons gross tonnage. In unfavourable conditions, for example, when the ship is pitching and rolling, an accuracy of about ± 5° can be obtained. On larger ships, the accuracy may be worse, but in most cases it should usually be possible to use the direction-finder for homing purposes on 2182 kHz. Bearings taken by reception of sky-waves, although variable in azimuth and sharpness, are useful for homing into the ground-wave range by utilizing their average value. 176 Rec. 488-1 RECOMMENDATION 488-1 * EQUIVALENT POWERS OF DOUBLE-SIDEBAND AND SINGLE-SIDEBAND RADIOTELEPHONE EMISSIONS IN THE MARITIME MOBILE SERVICE (1974-1990) The CCIR, CONSIDERING , (a) that according to provisions in force prior to 1 February 1992 of the International Convention for the Safety of Life at Sea, London, 1974, in the 2 MHz band using A3E emissions, it may be assumed that clearly perceptible signals will be obtained by day and under normal conditions and circumstances at 150 nautical miles by a power in the antenna of 15 W (unmodulated carrier) with an antenna efficiency of 27%; (b) that clearly perceptible signals are assumed to be received when the r.m.s. value of the field strength produced at the receiver by the unmodulated carrier is at least 25 pV/m; (c) that in normal operation the transmitter shall have a depth of modulation of at least 70% at peak intensity ; (d) that in the interest of more efficient spectrum utilization Resolution No. 306, Geneva, 1979, of the Radio Regulations requires the conversion by 1 January 1982, of all maritime emissions in the 2 MHz band to SSB except those on 2182 kHz, which may be A3E or H3E; (e) that the Safety Convention requires that transmitters use the classes of emission assigned by the Radio Regulations; (f) that to further improve efficient spectrum utilization all stations are constrained by the Radio Regulations to radiate no more than such power as is necessary to ensure a satisfactory service; (g) that the International Maritime Organization Resolution A.610(15) requires that the transmitter should be capable of transmitting upper sideband signals, where appropriate, using class of emission J3E and H3E with a peak envelope power during normal modulation emission of at least 60 W; (h) that SSB transmitters utilize R3E, H3E and J3E emissions; (j) that there is consequently a need to specify for each of the types of SSB emission, the powers and field strengths equivalent to those in the DSB system at present employed; (k) that cross-system operation between SSB and DSB equipments will at times be utilized, UNANIMOUSLY RECOMMENDS 1. that the bases for the calculation of .the field strengths of H3E, R3E and J3E emissions equivalent to a reference signal, which is an A3E emission for which the unmodulated carrier produces a field strength of 25 pV/m at the receiver, are as follows: 1.1 the signal-to-noise ratios at the output of the demodulator of all cases considered, including the reference case, are equal; 1.2 for single-tone modulation, the signal-to-noise ratio to be considered is only that of the fundamental component of the modulating tone at the output of the demodulator; 1.3 for class of emission A3E, the carrier is modulated by a single modulating tone to depths of 70% or 100%; 1.4 for class of emission H3E, the sideband amplitude for a single modulating tone is 70% or 100% of the carrier amplitude for equivalent 70% or 100% respectively, depths of modulation; 1.5 for class of emission R3E, the amplitude of the sideband signal corresponding to 70% and 100% modulations is the same as that for H3E in § 1.4‘but the carrier level is reduced to 16 dB below peak envelope power corresponding to 100% modulation; 1.6 for class of emission J3E, the amplitude of the sideband signal corresponding to 70% and 100% modulations is the same as that for H3E in § 1.4, but the carrier level is reduced by at least 40 dB below peak power corresponding to 100% modulation; * This Recommendation terminates the study of Question 19/8, which has been deleted. Rec. 488-1 177 2. that under the above conditions the calculated equivalent r.m.s. field strengths for the various classes of emission and for different types of receiving systems, with the types of test signals indicated, are shown in Table I: , TABLE I r.m.s. field strength (pV/m) equivalent to the reference signal Class Type (see § 1) of Test signal with a modulation depth of: of emission receiver 70% 100% (2) A3E DSB carrier only 25.0 25.0 A3E SSB carrier only 35.4 35.4 H3E DSB carrier only(‘) 26.8 29.4 H3E SSB carrier only 17.7 17.7 R3E SSB carrier and sideband 12.8 18.0 J3E SSB sideband only 12.4 17.7 (') Envelope detection of the H3E emission is assumed and this requires the reference field strength of 25 pV/m to be increased by 7% and 18% at 70% and 100% modulation, respectively, to compensate for the reduction in the amplitude of the fundamental component due to harmonic distortion in the detection process. (2) The calculations for 100% modulation are based upon the reference carrier (unmodulated) field strength of 25 pV/m. 3. that the calculated equivalent peak envelope powers into the antenna to achieve the field strengths given in § 2 are as listed in Table II; these powers are in all cases based upon a modulated signal: TABLE II Peak envelope power (W) equivalent to the reference signal (see § 1) Class of emission Type of receiver with a modulation depth of: 70% 100% A3E DSB 43.4 60 A3E SSB 86.7 120 H3E DSB 49.7 83.2 H3E SSB 21.7 30.0 R3E SSB 5.9 10.6 J3E SSB 3.7 ' 7.5 Note - The values given in this Table are valid irrespective of the type of modulating signal (i.e. single-tone, two-tone, smoothly-read text, etc.), provided the same modulation is used for all classes of emission. Note — The Director, CCIR, is requested to bring this Recommendation to the attention of IMO. 178 Rec. 489-1 R ECOM M ENDATIO N 489-1 TECHNICAL CHARACTERISTICS OF VHF RADIOTELEPHONE EQUIPMENT OPERATING IN THE MARITIME MOBILE SERVICE IN CHANNELS SPACED BY 25 kHz (1974-1978) The CCIR, CONSIDERING (a) that Resolution No. 308 of the World Administrative Radio Conference, Geneva, 1979, stipulates that: — the channel spacing for maritime mobile VHF radiotelephone services is being reduced from 50 kHz to 25 kHz; — the technical characteristics of equipment for 25 kHz channel spacing in these services shall be in accordance with Appendix 19 to the Radio Regulations, and that all equipment shall conform to 25 kHz standards by 1 January 1983; (b) that it is desirable to supplement the list of technical characteristics given in Appendix 19 to the Radio Regulations in the interests of reduction of interference and of compatibility between equipments; (c) that Appendix 18 to the Radio Regulations gives a table of transmitting frequencies which is based upon the principle of 25 kHz channel separations for the maritime mobile service; (d) that many administrations have already prepared their national specifications for this type of equipment and consequently it is not possible at the present time to reach international agreement on the detailed specification and measurement of some equipment characteristics; (e) that in Opinion 42, the IEC has been invited to advise the CCIR of any methods of measurement applicable to radio equipment used in land mobile services; and that such methods of measurement may also be suitable for radio equipment used in maritime mobile services, UNANIMOUSLY RECOMMENDS 1. that the following characteristics should be met by VHF (metric) FM radiotelephone equipment used for the maritime mobile services operating on the frequencies specified in Appendix 18 to the Radio Regulations; 1.1 General characteristics 1.1.1 The class of emission should be F3E/G3E. * 1.1.2 The necessary bandwidth should be 16 kHz. 1.1.3 Only phase modulation (frequency modulation with a pre-emphasis characteristic of 6 dB/octave) should be used. * 1.1.4 Where duplex or semi-duplex systems are in use, the performance of the radio equipment should continue to comply with all the requirements of this Recommendation. 1.1.5 The equipment should be designed so that frequency changes between assigned channels can be carried out within 5 s. . . 1.1.6 Emissions should be vertically polarized at the source. * 1.2 Transmitters 1.2.1 The frequency tolerance for coast station transmitters should not exceed 5 parts in 106, and that for ship station transmitters should not exceed 10 parts in 106. * 1.2.2 Spurious emissions on discrete frequencies, when measured in a nori-reactive load equal to the nominal output impedance of the transmitter, should be in accordance with the provisions of Appendix 8 of the Radio Regulations. 1.2.3 The carrier power for coast stations should not normally exceed 50 W. * * See also Radio Regulations, Appendix 19. Rec. 489-1 179 1.2.4 The carrier power for ship station transmitters should not exceed 25 W and means should be provided to readily reduce this to 1 W or less for use at short, ranges. 1.2.5 The frequency deviation should not exceed ± 5 kHz. * Deviation limiting circuits should be emplqyed such that the maximum frequency deviation attainable should be independent of the input audio frequency. 1.2.6 The Upper limit of the audio-frequency band should not exceed 3 kHz.* 1.2.7 The cabinet radiated power should not exceed 25 jxW. In some radio environments, lower values may be required. 1.3 Receivers 1.3.1 The reference sensitivity should be equal to or less than 2.0 pV, e.m.f., for a given reference signal-to-noise ratio at the output of the receiver. 1.3.2 The adjacent channel selectivity should be at least 70 dB. 1.3.3 The spurious response rejection ratio should be at least 70 dB. 1.3.4 The radio frequency intermodulation rejection ratio should be at least 65 dB. 1.3.5 The power of any conducted spurious emission, measured at the antenna terminals, should not exceed 2.0 nW at any discrete frequency. In some radio environments lower values may be required. 1.3.6 The effective radiated power of any cabinet radiated spurious emission on any frequency up to 70 MHz should not exceed 10 nW. Above 70 MHz, the spurious emissions should not exceed 10 nW by more than 6 dB/octave in frequency up to 1000 MHz. In some radio environments, lower values may be required. 2. that reference should also be made to Recommendations 331 and 332 and to the relevant IEC publications on methods of measurement. * See also Radio Regulations, Appendix 19. 180 Rec. 475-1 RECOMMENDATION 475-1 IMPROVEMENTS IN THE PERFORMANCE OF RADIOTELEPHONE CIRCUITS IN THE MF AND HF MARITIME MOBILE BANDS (Question 11/8) (1970-1974) The CCIR, CONSIDERING (a) that there is a need to improve the quality of transmission of MF and HF maritime mobile radiotelephone circuits; (b) that methods presently used usually employ voice-operated devices to eliminate instability or unwanted retransmission; (c) that such voice-operated devices frequently degrade the performance of the circuit; (d) that the use of conventional compressors and expanders on MF and HF circuits is inhibited by the variability of the transmission path loss; (e) that compressors and expanders may be linked to overcome this variability; (f) that such a system is already used by several administrations; (g) that further tests of this system may be necessary, and further systems may be proposed; (h) that when linked compressor and expander systems are used, it is necessary to ensure the compatibility of the equipment used by coast and ship stations, UNANIMOUSLY RECOMMENDS 1. that systems used in the international maritime mobile radiotelephone service should as far as possible maintain optimum modulation of the transmitter despite variations in subscribers’ speech volume and line losses; 2. that the speech and any control signals should both be contained within a 2700 Hz channel; 3. that administrations should be encouraged to continue their studies, and in the meantime, when it is desired to use a linked compressor and expander system, then in order to ensure compatibility between the sending and receiving stations, the characteristics of the equipment should be in accordance with Annexes I and II; for optimum performance, it is desirable that the characteristics of SSB radio equipment be in accordance with the minimum standards contained in Annex III. Annex I : Characteristics for ship stations. Annex II : Characteristics for coast stations. Annex III: Characteristics of SSB radio equipment. ANNEX I CHARACTERISTICS OFEQUIPMENT FOR SHIP STATIONS 1. Transmit side (Fig. la ) 1.1 Speech channel 1.1.1 Steady-state conditions For input levels between +5 dBmO and -2 5 dBmO the output levels should lie within the limits shown in Fig. 2. The overall amplitude/frequency response for the speech path, under both fixed-gain and controlled conditions, at any level within the range +5 dBmO to —25 dBmO should be: Frequencies Attenuation relative, to response at 800 Hz Above 300 Hz For frequencies in the band 350 Hz to 2300 Hz - 1 to +3 dB For frequencies in the band 2300 Hz to 2380 Hz - 1 to + 6 dB For frequencies in the band 2510 Hz and above > 50 dB Below 300 Hz Increase in overall gain for frequencies below 300 Hz < 1 dB 1.1.2 Transmit response (Overall) Attack time (Fig. 3a) (Note 1) 5 to 10 ms Recovery time (Fig. 3b) (Note 1) 15 to 30 ms Control channel Frequency-modulated oscillator Nominal centre frequency 2580 ± 1 Hz Maximum frequency deviation + 40 to —60 Hz Change of frequency for each 1 dB change of input levels (Fig. 4) 2 Hz Input level to transmit side to produce nominal centre frequency -2 5 dBmO Oscillator frequency resulting from an input level of + 5 dBmO 2520 Hz Oscillator frequency resulting from an input level of - 45 dBmO 2620 Hz Oscillator frequency when there is no input to transmit side < 2680 Hz For sudden increases in input that exceed 3 dB the time taken for the oscillator to complete 80% (10% to 90%) of the corresponding change in frequency should be 5 to 10 ms For sudden decreases in the input that exceed 10 dB the rate of change of the oscillator frequency should lie between 1.5 and 3.5 Hz/ms Upper limit of output spectrum , 2700 Hz Output level relative to test tone level in the speech channel * — 5 dB Receive side (Fig. \b) Speech channel 2.1.1 Fading regulator 2.1.1.1 Steady-state conditions For input levels between +7 dBmO and -3 5 dBmO the output should be within the limits shown in Fig. 5. 2.1.1.2 Transmit response Attack time (Fig. 3a) (Note 1) 7 to 13 ms Recovery time (Fig. 3b) (Note 1) 24 to 40 ms 2.1.2 Expander (controlled by the discriminator output) Effective dynamic range 60 dB When the combined line signal is adjusted in accordance with § 1.2 (control channel) the average power of the combined speech and control channel signals can be considered to be +4 dB relative to the level of the control channel signal by itself. Further, the speech peaks can be considered to be +12 dB relative to the control channel signal. 182 Rec. 475-1 Frequencies Attenuation relative to response at 800 Hz 2.2 Control channel 2.2.1 Amplitude/frequency and differential-delay characteristics o f filter Attenuation within the band 2520 Hz to 2640 Hz (relative to that at 2580 Hz) — 1 to + 3 dB Attenuation below 2400 Hz and above 2770 Hz (relative to that at 2580 Hz) ( > 50 dB Differential delay within the band 2520 Hz to 2640 Hz < 3.5 ms 2.2.2 Discriminator (Frequency/amplitude translator) Characteristics at nominal control-tone level Changes in the expander output with changes in the frequency of the control tone between 2520 Hz and 2640 Hz should be within the limits shown in Fig. 6 Nominal change in expander loss resulting from each 2 Hz in control-tone frequency 1 dB Control-tone frequency range over which 2 Hz per dB is main tained 2520 to 2640 Hz Receive-side output level for control-tone frequencies of: 2520 Hz + 5 dBmO 2640 Hz — 55 dBmO 2.2.3 Amplitude range o f discriminator A tolerance of ± 1 dB may be added to the performance require ments of § 2.2.2 for control-tone input level variations of 30 dB A tolerance of + 2 dB may be added to the performance require ments of § 2.2.2 for control-tone input level variations of 50 dB 2.3 Overall attack and recovery time (A sudden change of 24 Hz in the frequency of the control tone is used to simulate a 12 dB step) Attack time (Fig. 3c) 15 to 30 ms Recovery time (Fig. 3 d) 15 to 30 ms 3. Equalization of overall transmission time delay To avoid the necessity for the coast radio station to vary the amount of time delay equalization to cater for different designs of equipment, the control signal should lag behind the corresponding speech signal: 3.1 at the output of the transmit side by <4ms 3.2 at the expander (when the speech and associated control signal are simultaneously applied to the receive-side input) by 16 to 24 ms (Note 2) Note 1. — The definitions of attack and recovery time which are similar to those defined by the CCITT for compandors (Recommendation G.162) are as follows: — the attack time, of a compressor is defined as the time between the instant when a sudden increase of 12 dB in input is applied and the instant when the output voltage envelope reaches a value equal to 1.5 times its steady-state value; ' — the recovery time of a compressor is defined as the time between the instant when a sudden decrease of 12 dB in input is applied and the instant when the output voltage envelope reaches a value equal to 0.75 times its steady-state value. Note 2. — This delay includes an allowance for the time-constants of the circuits preceding the expander, in addition to that for the band-pass filter itself. Rec. 475-1 183 F i g u r e 1 a Transmit side F i g u r e lb Receive side A: frequency-modulated oscillator B: frequency discriminator C: fading regulator (constant volume amplifier) D: to radio transmitter E: from radio receiver Input.— L- Outpi t C om p ressor Input — L _ O u tp i t E xpand er 184 Output (dBmO), Input/output characteristic o f transm it side it transm f o characteristic Input/output e. 475-1 Rec. F gure r u ig 2 Rec. 475-1 185 12 dB step Input F ig u r e 3 a Output Vq Recovery time Input F i g u r e 3 b 186 Rec. 475-1 Attack time 24 Hz decrease F ig u r e 3 c Recovery time 24 Hz increase J F i g u r e 3d Control tone frequency (H z) 2618 2618 2622 aito of oto oefeuny ih hne ipt ee o h tas t side it transm the to level input f o changes with frequency tone control f o Variation Inputj output characteristic o f fading regulator f fading o characteristic output Inputj nu (dBmO) Input e. 475-1 Rec. nu (dBmO) Input F F gure r u ig gure r u ig 4 5 187 1. Transmit side (Fig. (Fig. side Transmit 1. 1,1 188 Speech channel Speech Control tone frequency (H z) n i. 8. Fig. in controlled conditions, at any level within the range +5 dBmO to —35 dBmO should be: should —35 dBmO dBmOto +5 range the within level any at conditions, controlled bv 0 z . Hz 300 Above Below 300 Hz 300 Below 1.1.1 For frequencies in the band 2510 and above > 50 dB 50 dB 1 > < Hz 300 below frequencies for gain above overall and in 2510 Increase band the in frequencies For and fixed-gain both under path, speech the for response amplitude/frequency overall The o rqece nte ad 30t 28 H -1 t +6 dB 6 + to dB 1 - +3 to 1 - Hz 2380 to 2300 Hz 2300 to 350 band the in frequencies For band the in frequencies For For input levels between +5 dBmO and —35 dBmO the output should lie between the limits shown shown limits the between lie should output —35the dBmO and dBmO +5 between levels input For Steady-state conditions Steady-state a) la STI OF EQUI OR COAS ONS N IO T A T S ST A O C R FO T N E M IP U Q E F O S IC T IS R E T C A R A H C Variation o f receive side output with changes o f control tone frequency tone control f o changes with output side receive f o Variation rqece Ateuto rltv to relative ttenuation A Frequencies NE II ANNEX e. 475-1 Rec. F igure 6 epne t 0 Hz H 800 at response Rec. 475-1 189 Frequencies Attenuation relative to response at 800 Hz 1.1.2 Transmit response (Overall) , Attack time (Fig. 9a) (Note 1) 5 to 10 ms Recovery time (Fig. 9b) (Note 1) ' 15 to 30 ms 1.2 Control channel Frequency-modulated oscillator Nominal centre frequency 2580 Hz Maximum frequency deviation ± 60 Hz Change of frequency for each 1 dB change of input level (Fig. 10) 2 Hz „ Input level to transmit side to produce nominal centre frequency — 25 dBmO Oscillator frequency resulting from art input level of 4* 5 dBmO 2520 Hz Oscillator frequency resulting from an input level of —55 dBmO 2640 Hz Oscillator frequency when there is no input to the transmit side < 2680 Hz For sudden increases in input that exceed 3 dB the time taken for the oscillator to complete 80% (10% to 90%) of the corresponding change in frequency should be 5 to 10 ms For sudden decreases in the input that exceed 10 dB the rate of change of oscillator frequency should lie between 1.5 and 3.5 Hz/ms Upper limit of spectrum 2700 Hz Output level relative to test tone level in the speech channel * - 5 dB 2. Receive side (Fig. lb ) 2.1 Speech channel 2.1.1 Fading regulator 2.1.1.1 Steady-state conditions For input levels between +7 dBmO and -3 5 dBmO the outputs should be within the limits shown in Fig. 11. 2.1.1.2 Transmit response Attack time (Fig. 9a) (Note 1) 7 to 13 ms Recovery time (Fig. 9b) (Note 1) 24 to 40 ms 2.1.2 Expander (controlled by the discriminator output) Effective dynamic range 50 dB * When the combined line signal is adjusted in accordance with § 1.2 (control channel) the average power of the combined speech and control channel signals can be considered to be +4 dB relative to the level of the control channel signal by itself. Further, the speech peaks can be considered to be 4-12 dB relative to the control channel signal. . 190 Rec. 475-1 Frequencies Attenuation relative to response at 800 Hz 2,2 Control channel 2.2.1 Amplitude/frequency and differential-delay characteristics o f filter Attenuation within the band 2520 Hz to 2640 Hz (relative to that at 2580 Hz) — 1 to +3 dB Attenuation below 2400 Hz and above 2770 Hz (relative to that at 2580 Hz) > 50 dB Differential delay within the band 2520 Hz to 2640 Hz < .3.5 ms 2.2.2 Discriminator (Frequency/amplitude translator) Characteristics at nominal control-tone level Changes in the expander output with changes in the frequency of the control tone between 2520 Hz and 2620 Hz should be within the limits shown in Fig. 12 Nominal change in expander loss resulting from each 2 Hz change in control-tone frequency 1 dB Control-tone frequency range over which 2 Hz per dB is main tained 2520 to 2620 Hz Receive-side output level for control-tone frequencies of: 2520 Hz + 5 dBmO 2620 Hz -4 5 dBmO 2.2.3 Amplitude range o f discriminator A tolerance of ± 1 dB may be added to the performance require ments of § 2.2.2 for control-tone input level variations of 30 dB A tolerance of ± 2 dB may be added to the performance require ments of § 2.2.2 for control-tone input level variations of 50 dB 2.3 Overall attack and recovery time (A sudden change of 24 Hz in the frequency of the control tone is used to simulate a 12 dB step) Attack time (Fig. 9c) 15 to 30 ms Recovery time (Fig. 9 d) 15 to 30 ms Equalization (overall) of transmission time Taking into account § 3 of Annex I for ship-station equipment, sufficient time delay shall be incorporated in the coast-station equipment to ensure that in both directions of transmission, the overall transmission times of the speech and control signals, as measured at the expanders, shall be equalized to within ± 8 ms Note. — The definitions of attack and recovery time which are similar to those defined by the CCITT for compandors (Recommendation G.162) are as follows: , — the attack time of a compressor is defined as the time between the instant when a sudden increase of 12 dB in input is applied and the instant when the output voltage envelope reaches a value equal to 1.5 times its steady-state value; — the recovery time of a Compressor is defined as the time between the instant when a sudden decrease of 12 dB in input is applied and the instant when the output voltage envelope reaches a value equal to 0.75 times its steady-state value. Rec. 475-1 191 F ig u r e la , Transmit side c 2^0^Hl > - HI m | F ig u r e lb Receive side A: frequency-modulated oscillator B: frequency discriminator C: fading regulator (constant volume amplifier) D: to radio transmitter E: from radio receiver Input — 1 I I I 1— Output Delay network I . J Input O utput C om p ressor Input O utput E xpander 192 Output (dBmO) Input joutput characteristic o f transm it side it transm f o characteristic joutput Input nu (dBmO) Input e. 475-1 Rec. F igure 8 Rec. 475-1 193 12 dB step Input F i g u r e 9 a Input F i g u r e 9b 194 Rec. 475-1 Attack time 24 H z decrease F i g u r e 9 c Recovery time 24 Hz increase F i g u r e 9 d Control tone frequency (Hz) 2641 2639 Variation o f control tone frequency with changes o f input level to the tran sm it side it sm tran the to level input f o changes with frequency tone control f o Variation nu/upt hrceitcof aig regulator f fading o characteristic Input/output nu (dBmO) Input nu (dBmO) Input e. 475-1 Rec. F F gure r u ig gure r u ig 10 11 195 196 Rec. 475-1 Receive side output (dBmO) F i g u r e 12 Variation o f receive side output with changes o f control tone frequency ANNEX III CHARACTERISTICS FOR SSB RADIO EQUIPMENT FOR OPTIMUM PERFORMANCE OF A LINKED COMPRESSOR AND EXPANDER SYSTEM A linked compressor and expander system can be applied with full advantage to the maritime mobile service using either DSB or SSB systems. To obtain the full advantages of the linked system when used with SSB radio equipment, the performance of the latter should meet the following requirements: 1. The short-term frequency stability of coast station transmitters should be within ± 2 Hz over a period of the order of fifteen minutes. 2. The short-term frequency stability of a ship station transmitter should be within ± 5 Hz over a period of the order of fifteen minutes. 3. To ensure sufficient overall gain stability of the system, for the duration of a call, facilities should be provided in coast station receivers to keep the end-to-end frequency error within ± 2 Hz; similarly, facilities should be provided in ship station receivers to keep the end-to-end frequency error within ± 5 Hz. 4. The permitted total amplitude variation in the radio transmitter over the 350 to 2700 Hz audiofrequency band should be 6 dB and the differential delay should not exceed 3 ms. The receiver should have at least the same standards of performance in these respects. 5. If the pilot carrier of a Type R3E emission is not used to provide a continuous signal for frequency and gain control of the receiver, for example where Type J3E emission is used, the initial tuning procedure will require the transmission for a brief period of a suitable reference tone (e.g. 1000 Hz ± 1 Hz) at a level of, say, -1 0 dBmO ± 0.5 dB. 6. Where it is desired to use privacy equipment or speech inverters, it should be borne in mind that, in Annex I of this Recommendation, the upper audio frequency of the speech channel is 2380 Hz. Rec. 542-1 197 RECOMMENDATION 542-1 * ON-BOARD COMMUNICATIONS BY MEANS OF PORTABLE RADIOTELEPHONE EQUIPMENT (Question 18/8) (1978-1982) The CCIR, CONSIDERING (a) that common channels for on-board communications are necessary to meet world-wide requirements; (b) that although the frequencies around 160 MHz as specified in Appendix 18 to the Radio Regulations are technically suitable for on-board communications, they are to an increasing extent required for other maritime needs; ■ (c) that frequencies in the UHF band around 460 MHz are technically suitable; (d) that on larger vessels it may not be possible to obtain satisfactory communications at all desired locations between two hand-carried transceivers; (e) that it is important to avoid interference from on-board communications stations to the fixed radio installation on a ship; (f) that no tests have yet been carried out on frequencies above 470 MHz, UNANIMOUSLY RECOMMENDS 1. that frequencies around 460 MHz are the most suitable of those so far tested for on-board communica tions, although other frequencies in the VHF and UHF bands are also technically suitable; 2. that the effective radiated power of on-board communication stations should be limited to the minimum required for satisfactory operation, but not exceeding 2 W** in the UHF band up to 470 MHz and 1 W** in the VHF band; 3. that the mode of operation between hand-carried transceivers should be single frequency simplex; 4. that, where the use of relays is necessary, frequencies with a spacing of the order of 10 MHz should be used for two-frequency simplex mode of operation, and the repeater stations should transmit only on the lower frequencies. * The Director of the CCIR is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO). ** For the purpose of type approval of equipment, the transmitter carrier power output terminated in its designed load impedance should not exceed 4 W and 2 W respectively (this takes into account typical feeder losses of relay transmitter installations and typical antenna efficiencies of hand-carried equipment). 198 Rec. 586-1 RECOMMENDATION 586-1 * AUTOMATED VHF/UHF MARITIME MOBILE TELEPHONE SYSTEM (Question 23/8) (1982-1986) The CCIR, CONSIDERING (a) that an automated VHF/UHF maritime mobile telephone service would expedite the handling of traffic in the international maritime mobile service and increase the efficient use of radio channels; (b) that there is an urgent need for such a service; (c) that a system providing such/a service could also allow for the transmission of, for example, telegraphy, facsimile and data; (d) that international standardization is of great importance in the maritime mobile service; (e) that the selective-calling system described in Recommendation 493 can form the basis for the signalling over the radio path and can provide for expansion to include other services; (f) Recommendation No. 312 of the World Administrative Radio Conference (Geneva, 1979), UNANIMOUSLY RECOMMENDS 1. that the automated VHF/UHF maritime mobile telephone system should be in accordance with either of the two configurations described in Annex I depending on channel availability, and geographical and other considerations; 2. that the signalling procedures to be used over the radio path should be in accordance with Annex II; 3. that the signalling messages to be transmitted over the radio path should be in accordance with Annex III. Note — Annexes IV and V provide supplementary information relevant to the operation of the automated VHF/UHF maritime radiotelephone system. ANNEX I SYSTEM DESCRIPTION 1. General 1.1 The two configurations described in this Annex differ only in their method of use of the calling channels. The marked idle channel (MIC) configuration is based on the assignment of non-shared channels to each coast station while the time division multiple access (TDMA) configuration is based on time sharing of a common calling channel by a number of coast stations. 1.2 Signalling procedures have been unified to the maximum extent feasible in order to minimize the additional cost for a ship station compatible with both configurations. Annex II to this Recommendation describes the signalling procedures in detail. The Director, CCIR, is requested to draw this Recommendation to the attention of the CCITT. Rec. §86-1 199 1.3 The signalling messages, described in Annex III to this Recommendation, are compatible with the digital selective-calling system (Recommendation 493). 1.4 In the following, a coastal area is defined as the geographic area covered by one or more coast stations controlled by a maritime switching centre (MSC). Note that the concept of a maritime switching centre does not preclude distributing the switching facilities at different locations. 2. Marked idle channel configuration This configuration has the following characteristics: 2.1 Shore-to^ship calling should be carried out over a channel marked either as “calling channel” (see § 2.4) or as “calling/idle working channel” (see § 2.7 and Note 1). - 2.2 Ship-to-shore calling should be carried out over a channel marked either as “idle working channel” (see § 2.5) or as “calling/idle working channel” (see § 2.7 and Note 1). 2.3 There is no need for the assignment of a dedicated frequency pair for a calling channel. However, administrations could provide for one or more dedicated calling frequencies, if this can be justified with respect to the number of available channels. 2.4 When at one coast station two or more channels are not in use for traffic at a given time: — one of these channels should be designated as the calling channel (for shore-to-ship calling) and should be marked with a unique “calling channel” signal Ml; — one or more of the remaining idle channels should be marked with a unique “idle working channel” signal M2. The number of idle working channels so marked is dependent on the expected number of ship-originated call attempts and the related probability of interference, etc., and should be determined by the administration for each coast station. 2.5 Idle channels not carrying the unique “idle working channel” marking signals would normally first be used for shore-originated traffic. 2.6 The designated “calling channel” should not be used for traffic unless all other channels of the coast station are occupied. 2.7 If, at any time, only one channel is not used for traffic, this channel may be marked with a unique “calling/idle working channel” signal M3 to allow for use for both shore-originated and ship-originated calling. 2.8 If all channels are occupied for traffic, no marking signals are transmitted by that coast station. 2.9 If, starting from the situation that all channels are occupied, one channel becomes free of traffic, this may then be marked as a “calling/idle working channel”. 2.10 If in addition to the “calling/idle working channel” a second channel becomes available, then the former channel should be marked (from that moment) with the “calling channel” marking signal. The second channel will then carry the “idle working channel” marking signal. 2.11 The marking signals should contain the coast station identification in accordance with Annex III to this Recommendation. 2.12 Since it is possible that more than one channel could be marked simultaneously with an “idle working channel” signal, ships should be provided with some means to randomize the selection of one of these idle channels for the call set-up procedure. 2.13 Marking signals sent on an idle working channel should be transmitted with reduced working power. Marking signals on the calling channel may also be sent at reduced power. However, calling sequences and signalling sequences should be sent at full working power. 2.14 During the on-hook condition the ship station may lock on a channel marked either “calling channel” or “calling/idle working channel”. 200 Rec. 586-1 When the ship is within radio coverage of several coast stations, the selection of which “calling channel” will be locked on may be based on signal quality measurements, such as field strength level or error-rate. In addition, provision should be made for manual or automatic selection of predetermined coast station identities by ship stations, e.g. coast stations of a particular nationality. 2.15 If a ship to coast station call attempt is unsuccessful, a second call attempt may be made after initiating a new search for an M2 or M3 marked working channel. After two unsuccessful call attempts the ship station should abandon the call and provide an unsuccessful call attempt indication to the ship subscriber. 3. Time division multiple access configuration (TDMA) This configuration has the following characteristics: 3.1 Shore-to-ship and ship-to-shore calling should be carried out over a dedicated calling channel which is a particular frequency pair, which may be time-shared by a number of coast stations. 3.2 The calling channel is marked with a unique “random access” signal M4 during the time, periods it is available for ship-to-shore call initiation (see § 3.4). 3.3 , In the shore-to-ship direction, coast stations within interference range of each other should coordinate their transmissions so that no overlap occurs. Such time-sharing may be either on the basis of pre-allocated time slots or on a demand basis. In the latter case, arrangements should be made to ensure that one high-traffic coast station does not lock out other participating coast stations for excessive periods of time. 3.4 In addition to time periods for shore station originated call attempts, time periods are provided on the calling channel to allow initiation of ship-originated calls using random access. During these periods the channel is marked with a unique “random access” marking signal. Each marking sequence should also indicate the number of random access time slots still to follow in the particular random access period. 3.5 Ship-to-shore call attempts should be transmitted only during the random access periods. Transmissions should be in time slots which are referenced to the “random access” marking sequences. To further enhance the channel capacity, ship stations should employ a means to randomize the choice of time slot following reception of a “random access” marking sequence, taking into account the number of time slots remaining (encoded in the marking sequence, see § 3.4). 3.6 When coast stations are allocated individual random access periods, coordination of the time periods is required between coast stations within interference range of each other. When a random access period is common to a number of coast stations, coordination between those coast stations should be effected to ensure full area coverage and non-interference of marking signals. 3.7 Upon receipt of a properly addressed call attempt from a coast station, the ship station shall immediately transmit its acknowledgement over the ship-to-shore frequency of the calling channel. 3.8 Upon receipt of a call attempt from a ship station, the appropriate coast station transmits a call sequence addressed to that ship station during its subsequent calling period. 3.9 Upon receipt of a location registration call attempt from a ship station (during the random access period) the appropriate coast station shall immediately transmit its acknowledgement over the shore-to-ship frequency of the calling channel. 4. Channel supervision If the quality of a speech channel decreases below a threshold level during the conversation, either the connection may be interrupted or a procedure may be started to switch the call-in-progress to a satisfactory working channel controlled by the same maritime switching centre (MSC). Two methods of channel quality supervision are given in Annex V of this Recommendation. The choice of the method used by each coast station may be decided by each administration; however, ship stations should be provided with facilities to enable the pilot tone method to be used, unless they sail only in waters where the pilot tone method is not used. Rec. 586-1 201 5. Location registration Location registration is defined as the procedure to be followed for the ship station identity to be entered in a ship location register at the controlling maritime switching centre (MSC). 5.1 To simplify the routing of calls in the shore-to-ship direction procedures are used to update the MSC’s location register. An updating procedure should be started >by the ship station when entering a new coastal area and when initially switching on a ship station. 5.2 Marked idle channel configuration 5.2.1 Location registration in the MIC configuration should take place on a working channel. 5.2.2 If during the on-hook condition the ship station loses the calling channel it is locked to, it will search for another calling channel. If the new calling channel marking signal indicates that the calling channel belongs to a different coast station, then the ship station may initiate a location registration procedure (see also Recommendation 587). , 5.3. TDMA configuration 5.3.1 Location registration in the TDMA configuration takes place on the calling channel. 5.3.2 If during the on-hook condition the ship station loses a particular coast station’s signal, it will search for another time slot. If the new coast station identification indicates that it is a different coast station, then the ship station may initiate a location registration procedure (see also Recommendation 587). 5.4 In both configurations: 5.4.1 Location registration is considered to be finalized after a confirmation by the new coast station. 5.4.2 If the ship does not receive a confirmation from the coast station, it repeats the transmission of the relevant signal. (In the MIC configuration the second trial should be made after initiating a new working channel search.) 5.4.3 If the ship has not received a confirmation after 2 successive trials, it should not make further trials to the coast station. In this case non-completion of the location registration procedure should be indicated on the ship’s equipment. 5.4.4 Administrations are urged to issue guidelines to avoid transmission of unnecessary location registration signals. 6. Polling Coast stations may be provided with facilities for polling. Polling is defined as the procedure by which an MSC can interrogate ships in order to verify whether they are still within radio coverage. Polling is done to keep track of ships already registered in the service area. Before deleting a ship from the register, several polling attempts should have been unsuccessful. 6.1 All signals necessary for polling should be transmitted on calling channels. Note 1 — No. 4908 of the Radio Regulations prohibits the use of devices for continuous or repetitive calling or identification; No. 4910 prohibits the emission of any carrier wave between calls. Therefore, continuous or repetitive marking of idle channels should be limited to the minimum required for the satisfactory operation of the system. Administrations are requested to reconsider this matter in preparing for the next competent World Administrative Radio Conference. 202 Rec. 586-1 ANNEX II SIGNALLING PROCEDURES 1. Introduction 1.1 Purpose The purpose of this part of the Recommendation is to describe the calling and signalling arrangements to be used over the radio path. The description uses sequence diagrams to show how signals are exchanged between a coast station and a ship station. In addition to the signalling over the radio path, interworking with the signalling over the public telephone network is necessary. Operation of the complete system is illustrated in Appendices I to VI (Note 1) using the specification and description language (SDL) developed by the CCITT. Appendix I provides a general introduc tion to SDL. Appendices II and III show logic procedures for land-originated calls at the maritime switching centre (MSC) and at the ship station, respectively. Appendices IV and V show logic procedures for ship-originated calls at the MSC and at the ship station, respectively. Appendix VI shows the procedure at the MSC for power level control and for switching call-in-progress. Procedures are defined for both TDMA and MIC configurations (see Annex I). The procedures are such that the differences are as small as possible so that ship stations may operate in both configurations, if required. Note 1 — Appendices I to VI are reproduced at the end of this Recommendation after Annex V. 1.2 Definition o f signals sent on the radio path 1.2.1 Marking sequences Ml — Signal used in MIC configuration to mark a channel as calling channel; M2 — signal used in MIC configuration to mark idle working channels; M3 — signal used in MIC configuration for combined calling/idle working channel marking; M4 — signal used in TDMA configuration to indicate available slot periods for ship-to-coast station1 call initiation. 1.2.2 Calling sequences Cl — Coast station to ship interrogation and polling signal; C2 — acknowledgement by ship to C l; C3 — coast station-to-ship call with indication of working channel; C4 — acknowledgement by ship to C3; C5X — coast station is unable to comply: X = 0 no reason given, X = 1 congestion at MSC, X = 2 ship barred, X = 3 queueing indicator (in TDMA configuration only), X = 4, ..., 9 reserved for future use; C6X — ship-to-coast station call: X = 0 no charging information requested, X. = 1 charging information requested; C7 — signal sent by coast station in TDMA configuration to acknowledge C60 or C61. C l includes indication of working channel; C8X — ship is unable to comply: X = 0 no reason given, X = 1 busy, v X = 2 acknowledgement to C53 (in TDMA configuration only), X = 3, ..., 9 reserved for future use; CIO — ship-to-coast station call for location registration; Cll — acknowledgement by coast station to CIO. Rec. 586-1 203 1.2.3 Signalling sequences SI OX — Coast station-to-ship signal to initiate continuity test of the working channel: X = 0 charging information available, X = 1. charging information not available; S2 — acknowledgement by ship to SI00 or S101; S3 — ringing command coast station-to-ship; S4 — answer signal from ship (off hook); S5X — call unsuccessful: X = 0 congestion, X = 1 busy, X = 2 send special information tone, X = 3, ..., 9 reserved for future use; S6 — “selection” signal sent by ship for ship-to-coast station calling. (Includes the called subscriber’s number); S7 — acknowledgement by coast station to S6; S8 — clearing by ship; S9 — clear acknowledgement to S8; S ll — clearing by coast station; S12 — clear acknowledgement to Sll; S13 — coast station-to-ship signal used for power level control and/or switching call-in-progress; S15 — coast station-to-ship signal to initiate continuity test on new working channel when switching call-in-progress; S16 — acknowledgement by ship to S13 or S15; S17 — coast station-to-ship signal to indicate start of chargeable duration and charging level, if available; S18 — acknowledgement by ship to SI7. 2. Call set-up and clearing procedures 2.1 Land-originated calls 2.1.1 Marked idle channel (MIC) configuration. Channels with M l marking sequences. • The call set-up and clearing procedures are shown in Fig. 1. 2.1.1.1 If the MSC does not require a ship interrogation prior to assigning the working channel, it sends the call signal C3 on the calling channel of the appropriate coast station. C3 contains the channel number of the assigned working channel. The ship will acknowledge C3 by sending the C4 signal on the return frequency of the calling channel. The MSC may continue to set up the call without awaiting the receipt of C4. However, the MSC must recognize and act upon a C80 or a C81 signal. 2.1.1.2 If the MSC requires a ship interrogation prior to assigning the working channel (e.g. it does not have accurate knowledge of the ship’s location), the MSC must transmit Cl on all coast stations in the required area. If the ship is in the required area, the MSC will receive the ship’s acknowledgement signal C2 from the coast station, the calling channel of which the ship is monitoring. The call set up would then continue as in § 2.1.1.1 above. 2.1.1.3 After having sent the call signal C3 on the calling channel, the MSC initiates the continuity check of the assigned working channel by sending the signal SI01 on that channel. 2.1.1.4 The ship will, after having sent C4, start monitoring the receive frequency of the assigned channel. The ship must not turn on its transmit carrier before S101 has been recognized. Upon recognition of S101 the ship returns the acknowledgement signal S2. However, if SI01 has not been received within three seconds, relative to the instant when C4 was sent, the ship should stop monitoring the working channel and reassume monitoring of a calling channel. 2.1.1.5 When the MSC recognizes the S2 signal, it will start transmitting the ringing command signal S3 and wait for the answer signal, S4, from the ship. 2.1.1.6 S101 should not be sent more than 8 times. If the MSC has not received an S2 signal during this time it should clear the land and radio connection. 2.1.1.7 When the ship station subscriber goes off hook, the ship station transmits S4. As soon as S4 has been recognized by the MSC it must stop transmitting S3 and wait for cessation of S4. If the ship fails to turn off S4 within three seconds after initial recognition of S4, by the MSC, the MSC should clear the call by sending SI 1. 204 Rec. 586-1 Maritime Ship switching ' station centre . • Calling Calling channel channel FIGURE 1 - Call set-up and clearing procedures for land-originated call MIC configuration with M l marking sequence X: any sequence (including Ml marking sequence) that may be sent on the calling channel. Rec. 586-1 205 2.1.1.8 A similar time-out supervision applies to the ship station. If S3 is still being received after S4 has been sent 8 times, the ship station should initiate clearing of the connection. 2.1.1.9 Through-connection at the MSC should not take place until cessation of S4 has been recognized. 2.1.1.10 Clearing may be initiated at any time during conversation by either party. 2.1.1.11 As soon as a clear forward signal is received from the telephone network, the coast station initiates clearing of the radio path by transmitting the Sll sequence to the ship. The MSC may either receive the acknowledgement S12 to Sll or the sequence S8 from the ship. The latter would occur if both parties clear simultaneously. The MSC deactivates the radio carrier as soon as the S12 or S8 sequence has been recognized. 2.1.1.12 If the ship subscriber clears first, i.e. the ship station has not recognized an Sll signal from the MSC when the on hook condition is detected, the ship station sends the S8 sequence. The ship station will either receive the acknowledgement S9 to S8 or the sequence Sll. The ship station deactivates the carrier as soon as the S9 or Sll sequence has been recognized. 2.1.1.13 The station that sends an acknowledgement sequence should deactivate its carrier as soon, as it ceases to receive the clearing sequence. 2.1.1.14 A clearing sequence or a clear acknowledgement sequence should not be sent more than 8 times. Upon time-out the station should deactivate its carrier. 2.1.2 Marked idle channel (MIC) configuration. Channels with M3 marking sequences. The. call set-up and clearing procedures are identical to those on channels with Ml marking sequences. However, it should be noted that: — in this case calling sequences and signalling sequences are sent on the same channel, i.e. on the M3 marked channel; — when a C3 signal is sent, the MSC must stop sending the M3 marking sequence until the channel has been released; — any C60 or C61 sequences received from a ship should be ignored after the channel has been seized for a land-originated call. 2.1.3 TDMA configuration The setting-up and clearing procedures are identical to that of the MIC configuration for channels with Ml marking. Ship-originated calls 2.2.1 Marked idle channel (MIC) configuration The set-up and clearing procedures are carried out on a working channel and are shown in Fig. 2. 2.2.1.1 When the MSC recognizes a C60 or C61 sequence it removes the M2 (M3) marking sequence (see § 2.1 of Annex IV). 2.2.1.2 If the received call sequence is C60, the MSC will transmit the S101 sequence in order to initiate the continuity check of the channel. If the received call sequence is C61, the MSC will return: — S100 if charging information can be provided. The detailed charging information will be provided later by use of the S17 sequence; — S101 if charging information cannot be provided. This would enable the ship station to bar calls for which charging information cannot be obtained. 2.2.1.3 Upon recognition of the SI00 or SI01 sequence the ship will return the S6 sequence containing all digits of the called number (including prefixes). If the ship station does not recognize SI00 or S101 within three seconds, it may automatically start a search for a new M2 (M3) marked channel and repeat the call on that channel without disconnecting the subscriber (see Annex I, § 2.15). 2.2.1.4 Upon recognition of a valid S6 sequence the MSC will return the acknowledgement sequence S7 until it ceases to receive the S6 sequence. At this instant the MSC may through-connect the call. 206 Rec. 586-1 Maritime switching centre Ship station Working channel Working channel FIGURE 2 - Call set-up and clearing procedures for ship-originated call. MIC configuration Note 1. - If requested by ship. J Rec. 586-1 207 2.2.1.5 The sequences S100, S101, S6 and S7 should not be sent more than 8 times. If no correct response is received within this time, the station times out and should clear the connection in the normal manner. 2.2.1.6 If the call sequence C61 was received from the ship, the MSC will send the sequence SI7 upon detection of the answer signal from the telephone network. The ship will acknowledge S17 with SI8. These signals are sent twice. 2.2.1.7 The ship station should be able to detect clearing by the on-board subscriber (on hook) at any time during the setting-up phase of the call and during conversation. In such cases the ship station should initiate clearing by transmitting the S8 sequence. The MSC will acknowledge S8 by S9. However, Sll may be received by the ship station instead of S9 if simultaneous clearing takes place. 2.2.1.8 The ship station should respond to the clearing sequence Sll from the MSC by returning the clear acknowledgement sequence S12 provided that the ship has not already started sending S8. In the latter case it should deactivate its carrier upon completion of S8. 2.2.1.9 Release of the radio channel should take place as described in § 2.1.1.13 and 2.1.1.14. 2.2.2 TDMA configuration without queueing The part of the call set-up procedure which takes place on the calling channel is shown in Fig. 3. The part of the procedure which will subsequently take place on the working channel is identical to that of the MIC configuration. Maritime switching centre Ship station Calling channel Calling channel FIGURE 3 - Call set-up procedure on calling channel for ship-originated call. TDMA configuration without queueing The ship transmits the call sequence C60 or C61 in a time slot during an M4 marked random access period. The MSC will respond in its next assigned calling period with the sequence C7 which includes the channel number of the assigned working channel. 2.2.3 TDMA configuration with queueing The part of the procedure which takes place on the calling channel is shown in Fig. 4. The part of the procedure which would subsequently take place on the working channel is identical to that of the MIC configuration. 208 Rec. 586-1 M a ritim e sw itching centre Ship station Calling channel ■ Calling channel FIGURE 4 - Calling procedure for ship-originated call. TDMA configuration with queueing 2.2.3.1 If there is no queue at the MSC when the call sequence C60 or C61 is received, the MSC acts as in § 2.2.2. 2.2.3.2 If there is a queue, the MSC will return C53 to indicate that the call has been placed in the queue. This signal is acknowledged with C82 by the ship. If no such acknowledgement is received within a predetermined time the MSC would assuipe that the ship has cleared. The C53/C82 cycle is repeated at periodic intervals until a channel becomes available at which time the MSC returns the C l sequence to the ship. Rec. 586-1 209 2.3 Unsuccessful calls 2.3.1 Land-originated calls 2.3.1.1 The ship station should have the capability of returning sequences C80 (unable to comply, reason not given) and C81 (busy). These sequences may be sent as a response to the call sequence C3. 2.3.2 Ship-originated calls 2.3.2.1 The MSC should respond to a C60 or C61 sequence by transmitting: — the C51 sequence if there is congestion in the MSC; — the C52 sequence if the calling ship is barred; — the C50 sequence if the MSC cannot comply to the call for any other reason (e.g. a request for service which is riot provided at the MSC). On receipt of one of these sequences the ship station should provide an appropriate information to the on-board subscriber. 2.3.2.2 On receipt of an electrical signal from the telephone network indicating that the connection cannot be established the MSC should return one of the sequences S50, S51 or S52 as appropriate, followed by the clearing sequence Sll. The sequences S50, S51 or S52 should be sent twice. 3. Location registration procedure 3.1 When a ship station initiates a location registration procedure, it sends CIO to the appropriate coast station. Upon receipt of CIO without transmission errors the coast station returns Cll to the ship station. If the ship station does not receive C ll, or if Cll is received with transmission errors, the ship station may repeat the location registration procedure or activate an indicator showing that the location registration was unsuccessful (see Annex I, § 5.4.2 and 5.4.3). 4. Polling procedure 4.1 When the coast station wishes to ascertain whether a registered ship is still in its service area it transmits Cl to the ship. Upon receipt of Cl the ship station returns C2 to the coast station (see also § 2.1.1.2). ANNEX III SIGNALLING MESSAGES 1. General The signalling required for setting up calls comprises: 1.1 marking sequences to indicate: - 1.1.1 in the marked idle channel configuration: — calling channels (Ml), — idle working channels (M2), — calling/idle working channels (M3); 1.1.2 in a time division multiple access configuration: — time-shared dedicated calling channels (M4); 1.2 calling sequences to alert the required station; 1.3 signalling sequences to establish and to clear the speech path on the radio channel. 2. Technical characteristics 2.1 The system is a synchronous system with the following characteristics: 2.1.1 The modulation rate is 1200 bauds. 2.1.2 Signalling is provided by frequency-shift keying of a sub-carrier in the voice band; the frequency shift is 800 Hz, the sub-carrier is at 1700 Hz (which is compatible with CCITT Recommendation V.23). The lower frequency is referred to as the Y (binary 1) state and the higher frequency as the B (binary 0) state of the signal elements. , 210 Rec. 586-1 2.1.3 The code is a ten-unit error detecting code: / — the first seven bits are the information bits; — the bits Nos. 8, 9 and 10 indicate, in the form of a binary number, the number of B elements in the seven information bits, as shown in Table I of Annex II to Recommendation 493; — the seven information bits of the primary code express a symbol number from 0 to 127 inclusive as shown in Table I of Annex II to Recommendation 493; — the symbols from 0 to 99 inclusive are used to code two decimal figures according to Table IVa of Annex II to Recommendation 493; — the symbols from 100 to 127 inclusive are used to code service commands. 2.1.4 Apart from the phasing signals, each signal is transmitted twice in a time-spread mode; the first transmission (DX) of a specific signal is followed by the transmission of four other signals before the re-transmission (RX) of that specific signal takes place, allowing for a time-diversity reception interval of 33.3 ms. 2.2 General format o f marking, calling and signalling sequences The general format is shown in Fig. 5. M essage Self- P hasing Form at O ther E n d o f C heck A ddress C ategory id en ti T ele seq u en ce specifier infor se q u en ce character fication com m and m ation A B C D E F l F2 G H FIGURE 5 - General form at of sequences 2.2.1 The phasing sequence is identical for all sequences and is composed of the signals 125 in the DX-position (four times) and sequentially the signals 109, 108, 107, 106, 105 and 104 in the RX- position as shown in Fig. 6. DX 125 125 125 125 110 Xi x 2 M arking seq u en ce RX 109 108 107 106 105 104 110 DX 125 125 125 125 120 x, x 2 C alling seq u en ce RX 109 108 107 106 105 104 120 DX 125 125 125 125 124 x, X2 S ignalling seq u en ce RX 109 108 107 106 105 104 124 F IG U R E 6 - Composition of the phasing sequence and the form at specifiers Xj and X2: the first two characters of self identification (marking sequences) or address (calling and signalling sequences) in DX position. 2.2.2 The format specifier defines the type of sequence and is in accordance with Recommendation 493: — signal 110 is used to define a marking sequence; — signal 120 is used to define a calling sequence being a selective call directed to an individual station; — signal 124 is used to define a signalling sequence. Rec. 586-1 211 2.2.3 The end o f sequence. consists in the DX-position of three identical signals (Gi, G2, G3) of which G2 and G3 are DX-stuffing signals to obtain time-diversity reception. In the RX-position only Gj is sent as shown in Fig. 7. . DX G, G2 g 3 R X *n-2 Xn-1 x n G, a) End of sequence for a single frame DX Xn G1 g 2 G.3 125 125 RX Xn -2 Xn-, Xn G, 109 b) End of sequence for multiple frames FIGURE 7 - Composition of end of sequence In all types of sequences the G signal may be: — 117, if the sequence requests an acknowledgement (RQ); — 122, if the sequence is an acknowledgement (BQ); — 127, if the sequence does not need to be acknowledged and is not an acknowledgement (END). \ 2.2.4 The error check character (E) is transmitted in the DX-position immediately after the signal Xn_! and in the RX-position immediately after the signal G3 as shown in Fig. 8. DX x n G, E g 2 Gj R X Xn-2 x n-, x n G, E a) End of sequence and error check character for single frames 125 DX x n G, E g 2 Gj 125 R X E 109 Xn-2 Xn-, x n G1 b) End of sequence and error check character for multiple frames F IG U R E 8 - The composition of the end of sequence when an error-check character is incorporated The seven information bits of the error check character are equal to the least significant bit of the modulo-2 sums of the corresponding bits of all information characters starting with the format specifier and including the end-of-sequence character (separator characters, if any, are also considered to be information characters). 212 Rec. 586-1 2.2.5 The address and the self-identification are the identities of the called and the calling station respectively and are coded in accordance with Table IVa of Annex II to Recommendation 493. The ship identity comprises five signals: MI DX4 X5X6 X7X8 X90 The coast station identity also comprises five signals: ' 00 MI DX6 X7X8 X90 (see Recommendation 587). 2.3 Marking sequences The general format for marking sequences is given in Fig. 9 and the composition in Table I. The definition of marking sequences is given in § 1.2.1 of Annex II. 2.3.1 A marking sequence does not contain the address and the category. 2.3.2 The phasing sequence and the format specifier (110) are as shown in Fig. 6. 2.3.3 Self-identification is the coast station identity as defined in § 2.2.5. 2.3.4 The telecommand character identifies the type of marking sequence: M l: 101 M2: 102 M3: 103 M4: 104. M essage Self- P hasing F orm at End o f id en ti seq u en ce sp ecifier seq u en ce fication T ele- . O ther com m an d information A B E F l F2 G FIGURE 9 - Format of a marking sequence 2.3.5 Other information is as follows: — Channel information and power level control comprising three characters: 8 A 2 A 3 A 4 A 5 A 6 where A2 indicates the power level as follows: A2 = 0, maximum power level; A2 = 1, power level not exceeded 2.5 W; A2 = 2, power level not exceeding 250 mW; A2 — 3 through 9 are reserved for future use; and A3A4A5A6 indicates the channel number of the marked channel; It should be mandatory that the ship station equipment is provided with the power levels corresponding to A2 — 0 and 1. The level corresponding to A2 = 2 may be used on a national basis. When only the mandatory levels are provided in the ship station equipment the response to A2 # 0 should * be the level corresponding to A2 = 1. Note — In certain regions of inland waterways administrations concerned may mutually agree that only ship stations which are capable of a power level not exceeding 250 mW will be admitted to the service. — In addition, the M4 sequence contains a message 9Z2 Z3Z4 indicating the number of random access time slots still to follow. This information is separated from the above by signal 126. 2.3.6 The end of sequence 127 is sent as shown in Fig. 7. Rec. 586-1 213 2.4 Calling sequence The general format of calling sequences is given in Fig. 5 and the composition in Table II. The definition of calling sequences is given in § 1.2.2 of Annex II. 2.4.1 The phasing sequence and the format specifier (120) are sent as shown in Fig. 6. 2.4.2 The address and the self-identification are as defined in § 2.2.5. 2.4.3 The category signal is 100 (routine) for all calling sequences.. 2.4.4 The telecommand character is: 101 (telephony) for C3, C4, C60, C61 and C7; 121 (up-dating information) for CIO and C ll; 103 (polling) for signals Cl and C2; ' 104 (unable to comply) for signals C50, C51, C52, C53, C80, C81 and C82. Note — If other services are introduced a telecommand character other than 101 should be used for signals C3, C4, C60, C61 and C7 in accordance with Tables Va and Vb of Annex II to Recommenda tion 493. 2.4.5 Other information includes: — For signals Cl, C3 and C7 the channel number and power level control indication of the actually used channel, comprising three characters, 8A2 A3A4 A5A6, where A2 indicates the power levels as follows: A2 = 0, maximum power level;: A2 = 1, power level not exceeding 2.5 W; A2 = 2, power level not exceeding 250 mW; A2 = 3 through 9 are reserved for future use; A3A4A5A6 indicates the channel number of the channel on which the signal is sent. It should be mandatory that the ship station equipment is provided with the power levels corresponding to A2 = 0 and 1. The level corresponding to A2 = 2 may be used on a national basis. When only the mandatory levels are provided in the ship station equipment the response to A2 =£ 0 should be the level corresponding to A2 = 1 (see Note in § 2.3.5). — For signals CIO the character 80 and the channel number of the actually used channel A3A4A5A6 ; — For signals C60 and C61 request for charging information and the channel number of the actually used channel 8A2 A3A4 A5A6 where A2 = 0, indicates that no charging information is requested (signal C60); A2 = 1, indicates that charging information is requested (signal C61); A3A4A5A6, indicates the number of the actually used channel; — the symbols 100, 101, 104, 103, 100, 102 and 103 are used as a second telecommand character in the call sequences C50, C51, C52, C53, C80, C81 and C82 respectively. Sequence C53 may contain an additional character QiQ2 indicating the length of the queue at the MSC; — in addition the call sequences C3, C60, C61 and C7 include the character 90 followed by the characters B3B4 and B5B6 where B3B4B5B6 indicates the number of the assigned channel; A — in TDMA configurations the call sequences C60 and C61 may contain optional channel information for ships which do not have multi-working channel capability. 2.4.6 The end of sequence is sent as shown in Fig. 8 and has the values shown in Table II. 2.4.7 All calling sequences comprise an error check character E. 2.5 Signalling sequences The general format for signalling sequences is given in Fig. 5 and the composition in Table III. The definition of the signalling sequences is given in § 1.2.3 of Annex II. 2.5.1 The phasing sequence and the format specifier (124) are sent as shown in Fig. 6. 2.5.2 The address and the self-identification are as defined in § 2.2.5. 2.5.3 The category character is 100 for all signalling sequences. 214 Rec. 586-1 2.5.4 The telecommand character is: lOOforSlOO 101 for S101 and S2 102 for S3 and S4 103 for S8, S9, S ll and S12 104 for S17 and SI8 105 for S7 107 for SI3 108 for S15 and S16 109 for S50, S51 and S52. For S6 the telecommand character is 105 if the called number (including prefixes) has an odd number of digits and 106 if it has an even number of digits. 2.5.5 Other information included in the signalling sequences S5X, S6, S9, Sll, S13 and SI7: — the symbols Nos. 101, 102 and 100 are used in the signalling sequences S50, S51 and S52 respectively; — S6 contains all digits of the called number. If the called number has an odd number of digits, a stuffing digit 0 will be used in the T] position (see Table III). Examples of coding of subscriber numbers of various length are given in Table IV; — S9 and Sll contain information of the calling channel in use at the coast station, A3A4A5A6 indicating the calling channel number; — SI3 contains a channel indication 9B2 B3B4 B5B6 where B2 indicates the power level as follows: B2 = 0,maximum power level; B2 = 1, power level not exceeding 2.5 W;. B2 = 2,power level not exceeding 250 mW; B2 = 3 through 9 are reserved for future use. The digits B3B4B5B6 are the channel number. If S13 is used for power level control only, B3B4B5B6 is the channel number of the channel in use. Otherwise it indicates the channel to which the call has to be switched. It is mandatory that the ship station equipment is provided with the power levels corresponding to B2 = 0 and 1. The level corresponding to B2 = 2 may be used on a national basis. When only the mandatory levels are provided in the ship station equipment the response to B2 =£ 0 should be the level corresponding to B2 = 1 (see Note in § 2.3.5). — S17 contains charging information P!P 2 P 3 P4. If charging information cannot be provided, P]P 2 P 3 P 4 will be 0000 and S17 may be used to indicate the start of the chargeable duration. 2.5.6 The end of sequence is sent as shown in Fig. 8 and has the values shown in Table III. 2.5.7 All signalling sequences comprise an error check character E. TABLE I - Composition of marking sequences M l M 2 M3 M4 Format specifier 1 1 0 1 1 0 1 1 0 1 1 0 0 0 0 0 0 0 0 0 Self-identification MI MI MI MI DX, DX, DX, DX, (coast station identity) x 7x 8 , X 7x 8 X 7 X 8 X 7 X 8 XgO x „ o XgO X.,0 Telecommand 1 0 1 1 0 2 103 104 Power level 8 A 2 8 A 2 8 A 2 o I a 3 a , > 0 0 A 3 A, Own channel number j A 3 A 4 a 5 a . A 5 A, > A 5 A , S Separator 126 Number of random access time slots 9Z 2 still to follow (TDMA only) Z 3 Z 4 End of sequence 127. 127 127 -127 Duration (ms) 283.3 283.3 283.3 333.3 TABLE II - Composition of calling sequences C l C2 C3 C4 C50 j C51 | C52 | C53 C60 | C61 C l C80 | C81 | C82 CIO C ll Format specifier 1 2 0 1 2 0 1 2 0 1 2 0 1 2 0 | 1 2 0 | 1 2 0 | 1 2 0 1 2 0 | 1 2 0 1 2 0 1 2 0 | 1 2 0 ] 1 2 0 1 2 0 1 2 0 MI 0 0 MI 0 0 MI 0 0 MI 0 0 0 0 MI DX 4 MI DX 4 MI DX, MI DX, MI MI DX A dd ress: DX, DX, DX, ship - or coast-station identity XX XX XX XX DX DX XX X 7 X 8 XX X 7 x 8 X 7 x 8 X 7 x 8 X 7 x 8 X 7 X 8 x 7 x 8 x 7 x 8 XX X 9 O X ,0 X 0 X 0 X 0 X 0 X 0 X 0 X 0 X) Category 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 ! 1 0 0 \ 1 0 0 ! 1 0 0 1 0 0 ! 1 0 0 . 1 0 0 1 0 0 ! 1 0 0 i 1 0 0 1 0 0 1 0 0 0 0 MI 0 0 MI 0 0 MI 0 0 MI MI . 0 0 MI DX 4 MI DX, MI DX, MI DX DX MI Self-identification: DX, DX, X 5 X, ship - or coast-station identity DX XX XX DX xx XX DX X 7 X g X 7 X 8 X 7 x 8 X 7 x 8 X 7 x 8 . X 7 X 8 X 7 X 8 x 7 x 8 x 7 x 8 XX X , 0 X 0 X 0 X 0 X 9 0 X 0 X 0 X 0 X 0 X 0 First telecommand 103 103 1 0 1 1 0 1 104 | 104 | 104 | 104 1 0 1 ! 1 0 1 1 0 1 1Q4 ! 104 j 104 1 2 1 1 2 1 1 Second telecommand 100 | 101 | 104 | 103 100 ! 102 ! 103 . 1 1 1 1 1 1 8 A 2 8 A 2 80 | 81 8 A 2 . 80 « Other information, A 3 A 4 A 3 A 4 a 3 a , | a 3 a , a 3 a , a 3 a , g own channel number ! 1 1 Q1Q2 A 5 A, A 5 A, A sA , | a 5 a . A 5 A, A 5 A, 1 1 1 1 1 90 90 | 90 , 90 1 1 Working channel number b 3 b 4 b 3 b 4 1 b 3 b 4 b 3 b 4 b 5 b , b 5 b , 1 b 5 b . b 5 b , End of sequence 117 1 2 2 117 1 2 2 127 1 127 1 127 1 127 117 1 117 1 2 2 127 1 127 1 127 117 1 2 2 Error check character E E E E E l E I E I E E 1 E E E 1 E 1 E E E 1 1 D uration o f sequen ce M IC: 400 400 350 466,7 350 366,7 | 366,7 | 366,7 383,3 466,7 366,7 | 366,7 | 366,7 400 350 (m s) | TDMA: 466,7 ------i...... 1...... TABLE III - Composition of signalling sequences S100 S101 S2 S3 S4 S50 S51 S52 S6 (') S7 S8 S9 Sll S12 S13 S15 S16 S17 S18 Format specifier 124 124 124 124 124 124 124 124 124 124 124 124 124 124 124 124 124 124 124 1—1 MI MI 00 MI 00 MI MI MI 00 MI 00 MI > 00 00 MI 00 MI 00 00 00 MI 00 MI 00 00 MI 00 00 MI 00 MI Self-identificafion: MI MI DX MI DX MI MI MI DX MI DX MI MI DX MI MI DX MI DX ship - or coast-station identity DXg DX XX DX XX DX DX DX XX DX XX DX DX XX DX DX XX DX XX X7x 8 X7X8 XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXg x x 8 X0 X0 X0 X0 X0 Xo X0 X0 XO XO XO XO XO XO XO XO XO XO XO Telecommand 105/k 100 101 101 102 102 109 - 109 109 106u 105 103 103 103 103 107 108 108 104 104 101 102 100 t ,t 2 80 80 9B2 P,P2 t 3t 4 A 3A 4 b3b4 U XX P3P4 OX) t 5t 6 XX XX B5B6 8 Other information TABLE IV - Examples of coding of subscriber numbers of various length in the S6 sequence a) b) c) d) e) X<,0 X.,0 X,0 X90 X.,0 106 106 106 105 105 Telecommand 11 00 00 03 12 01 11 34 23 23 56 45 117 117 117 117 117 End of sequence . E E E E E Error check character a ) No digit information required. Telecommand 106 (even number of digits) followed by end of sequence 117. b) Prefix 11 only. Telecommand 106 (even number of digits). c) Prefix 00 and international number 12 34 56. Telecommand 106 (even number of digits including prefix digits). d) Prefix 00 and international number 123 45. Telecommand 105 (odd number of digits): stuffing digit 0 underlined. e) Prefix 31 and number 123. Telecommand 105 (odd number of digits): stuffing digit 0 underlined. ANNEX IV TIMING REQUIREMENTS 1. Shore-originated calling 1.1 When a coast station transmits a call sequence on the shore-to-ship frequency of the calling channel the ship sends , a reply or an acknowledgement sequence on the ship-to-shore frequency of the same channel. Overlap between successive reply sequences of different ships cannot occur since the coast station call sequences are sufficiently longer than the ship reply sequence. 1.2 The ship station response time is the time between the end of coast station calling sequence and the beginning of the call acknowledgement message sequence indicated as t3 in Fig. 10. Typically t3 may be 30 ms ± 10%. The following partial times are of interest: — the time interval from the end of the calling sequence until the instant that the transmitter output power is 40 dB below its steady-state value is indicated as in Fig. 10; — because of the reaction time of the coast station squelch, the ship station must always wait a time,t2 before data signalling starts. This time interval, taken from the time that the transmitter output reaches a value of 2 dB below its steady-state output power, is shown in Fig. 10. Provisionally, t2 should be at least 7 ms; — the transmitter decay time is defined as the time interval from the end of the call acknowledgement until the instant that the transmitter output power has decayed to a value of 40 dB below its steady-state value, and is indicated as t4 in Fig. 10. Provisionally, t4 should be less than 20 ms. 1.3 The above discussion is equally applicable to the MIC and the TDMA configurations. 218 Rec. 586-1 dB F IG U R E 10 - Timing diagram t 0: end of coast station-to-ship calling sequence. 2. Ship-originated calling 2.1 Marked idle-channel (MIC) configuration When a ship seizes an idle working (or calling/idle working) channel, it is important that the coast station removes the marking sequence before the next marking sequence is completed. Otherwise, another ship might try to seize the channel on recognition of this next marking sequence and thus cause overlap transmission. Fig. 11 illustrates this procedure. The delays between the end of the last complete marking signal and the interrupt are: — twice the one-way delay encountered on the landline between coast station and MSC (if separated); — maximum turn-around time of the ship station; — signal acquisition and processing time at the coast station/MSC. For very long feeder lines between coast station and the MSC a maximum (one-way) delay of 10 ms may be assumed reasonable, and a maximum ship’s station turn-around time of 33 ms was indicated in § 1.2 above. With a minimum length of the marking signal of 283.3 ms the interrupt should occur before the first end-of-sequence character, i.e. within 233.3 ms. Using these values would put an upper bound on the combined signal acquisition and processing time of approximately 180 ms. 2.2 TDMA configuration ./ ' ■ .. ' ' Determination of the length of the time slots in the random access period is based on the following assumptions: — while on-hook, the ship’s timer is resynchronized by each received signal; — the maximum interval between received signals is 10 time slots; — the accuracy of the ship’s timer is at least ± 1%. Rec. 586-1 219 With a ship station turn-around time of 30 ms ± 10% (see § 1.2 above) and a ship’s call request message length of 450 ms the minimum time slot length should be approximately 530 ms. M arking M arking M arki Shore-to-ship seq u en ce seq u en ce seq u e freq u ency I r Interrupt S h ip ’s Ship-to-shore call freq u ency FIGURE 11 - Interruption of marking sequence ANNEX V CHANNEL QUALITY SUPERVISION 1. Channel quality supervision by means of carrier level measurement The channel quality is supervised by continuously measuring the field strength of the radio carrier at the coast station. This method monitors only the ship-to-coast station direction of the radio path. No special provision is required at the ship station. 2. Channel quality supervision by use of pilot tones 2.1 General The channel quality is continuously supervised at the coast station by modulating a pilot tone on the radio carrier together with the voice band signal. The ship stations must be capable of looping back such pilot tones on the return channel. With this method both directions of the radio path are monitored. 2.2 Pilot frequency The pilot frequency could be any single tone within the frequency range 3900* to 4100* Hz. The ship station should be able to return any signal, including noise, received within a 6 dB bandwidth of 400* Hz with a centre frequency at 4000 * Hz. Pilot tone frequency offsets should be employed in multiple coast station areas to avoid interference problems. 2.3 Peak frequency deviation The peak frequency deviation produced by the pilot tone both at the ship station and at the coast station should be 300* Hz ± 30* Hz. * Provisional value. 220 Rec. 586-1 2.4 Loop-back filter The attenuation characteristic of the loop-back filter is given in Fig. 12. «•a OS 8000 Modulation frequency FIGURE 12 - Attenuation characteristics for the loop-back filter in the mobile station APPENDICES (ANNEX II) APPENDIX I GENERAL INTRODUCTION TO SPECIFICATION AND DESCRIPTION LANGUAGE (SDL) 1. General In Appendices II to VI the calling and signalling arrangements to be used over the radio path are illustrated using the specification and description language (SDL) developed by the CCITT. A full description of SDL is contained in CCITT Recommendations Z.101 to Z.104. Application of SDL to interworking of telephone signalling systems is found in the Q.600 to Q.699 series of CCITT Recommendations. 2. Descriptive tools 2.1 Basic concepts SDL is based on state transition diagrams. A signalling process consists of several states and the various transitions between them. The system is in a given state until an input signal is received. The input will force the process to travel along a transition, executing tasks, generating outputs and branching on decisions until another state is reached. The concepts of state, input, task, output and decision are represented with standard symbols. The interconnection of such symbols by flow lines represents the logical flow of a process. Rec. 586-1 221 2.2 Graphical symbols Only a small set of graphical symbols is required to present a signalling system. The following symbols are required: States p T ~ . Ir Descriptive text \\ 1 -ff- state number I of the state I Inputs: Forward input signal* I Backward input signal* Internal input signal Outputs: > Forward output signal* < Backward output signal* > Internal output signal Task symbol: Decisions: Binary decision Multiple decision T I * A forward signal is sent in the direction of the called subscriber. A backward signal is sent in the direction of the calling subscriber. 222 Rec. 586-1 Connectors: Out-connector No. 1: the corresponding in-connector is given on sheet 2. In-connector No. 1: the corresponding © out-connectors are given on sheets 1, 2 and 3. 1, 2, 3 I 1, 2, 3 Timers: Start t > - [ Start of tinier Stop t > Stop timer I Expiry of timer Counters are introduced as replacement of timers in cases where signals should only be sent a given number of times. The following symbols are used: Start counter Start of counter Stop counter Reset of counter Counter limit n has been reached 2.3 FITEs, BITEs and SPITEs Forward interworking telephony events (FITEs) and backward interworking telephony events (BITEs) are used to standardize events that may occur on the interface between an incoming and an outgoing signalling system (e.g. between the incoming telephone signalling system and the MSC-to-ship signalling system). Switching process interworking telephony events (SPITEs) are used internally in the MSC. Rec. 586-1 223 Tables V, Vi and VII list all FITEs, BITEs and SPITEs used in Appendices II and IV. These and other events have been specified by the CCITT and a full list is given in CCITT Recommendation Q.608. TABLE V - FITEs used in Appendices II and IV FITE Corresponding or No. Meaning equivalent call/ signalling sequence 1 Digit 1, 2,..., 9 or 0; C3, S6 or end-of-pulsing 15 Calling party’s category C3 subscriber (routine) (telecommand character) 22 Clear forward S8, Sll TABLE VI - BITEs used in Appendices II and IV BITE Corresponding or No. Meaning equivalent call/ signalling sequence 5 Address complete, charge S2 11 Call unsuccessful, switching S50 equipment congestion 16 Call unsuccessful, address S51, C81 complete, subscriber busy 20 Call unsuccessful, send special S52, C80 information tone 22 Answer, subscriber free, charge S17, S4 25 Clear back S8 27 Sending finished, set up - speech condition 29(‘) Release incoming side Sll (') Not presently used by the CCITT. 224 Rec. 586-1 TABLE VII - SPITEs used in Appendices II and IV SPITE M eaning Sym bol N o. 1 Activate register function task 3 Deactivate register function task 4 Set up speech condition task 6 Return appropriate tone (ringing tone, congestion tone, busy tone, special information tone) task 6 A Remove tone task 1 2 Perform digit analysis task 13 Digit analysis cannot be completed input 14 Routing information input 15 Unallocated number - input 16 Unprovided routing input 17 Barred routing input 18 Switching equipment congestion input 19 Circuit group congestion input 2.4 The signals sent on the radio path are defined in § 1.2 of Annex II. 3. SDL diagrams 3.1 Outgoing procedure at M SC (land-originated call) 3.1.1 The SDL diagrams are given in Appendix II. 3.1.2 The following supervisory timers are used in the diagrams: Type of timer time-out state sheet Timer h I s 02 1 Counter nt 2 times 02 1 Counter n2 8 times 04 2 Timer t2 3 s 06 3 Counter n3 8 times 08,09 3 3.2 Incoming procedure at ship (land-originated call) 3.2.1 The SDL diagrams are given in Appendix III. 3.2.2 The following supervisory timers are used in the diagrams: Type of timer time-out state sheet Timer t\ 3 s . 01 1 Counter «] 8 times 02 1 Counter n2 8 times 04 2 06 2 Counter n3 8 times 08 3 Timer t2 3 s 07 3 Rec. 586-1 225 3.3 Incoming procedure at MSC 3.3.1 The SDL diagrams are given in Appendix IV. 3.3.2 The following supervisory timers are used in the diagrams: Type of timer time-out state sheet Timer t{ I s 01 1 Timer t2 *' 02 1 Timer' /3 * 03 1 Counter nx 8 times 05,06 2 Counter n3 2 times 09 3 Timer t5 3 s 10 3 Counter n4 8 times 12,13 4 3.4 Outgoing procedure at ship (ship-originated call) 3.4.1 The SDL diagrams are given in Appendix V. 3.4.2 The following supervisory timers are used in the diagrams: Type of timer time-out state sheet Timer tx * 02 1 Timer t2 * 04 1 Timer /3 * 05 1 Timer t4 3 s 06 2 Counter nx 8 times 07 2 Timer t5 3 s 08 2 Timer t6 3 s 10 3 Counter n4 8 times 11,12 3 3.5 Power level control and switching call-in-progress control at MSC 3.5.1 The SDL diagrams are given in Appendix VI. 3.5.2 The following supervisory timers are used in the diagrams: Type of,timer time-out state sheet Timer tx 2 s 01 1 Timer t2 3 s 03 2 Counter n2 5 times 03 2 Counter nx 3 times 03 2 Counter n3 8 times 03,04 2 * Not yet defined. 226 Rec. 586-1 APPENDIX II S heet 1 Connector References Outgoing procedure at MSC (land-originated call) Rec. 586-1 227 APPENDIX II Sheet 2 C onnector references 1 £ C o n n ect equipment to working channel A ctiv ate w o rk in g channel carrier S 1 0 1 > Start counter - [n 2 = i n2 > 0 4 W ait V ( I I I ■ ■ I ■■■ I S 2 ^ ^ FITE 2 2 ^ n2 C 8 0 ^ o 00 C 6X /\ Stop Ignore sen ding of BITE 16 BITE 11 BITE 2 0 signal S 1 0 1 x : ~ r ~ Stop counter S top n2 sen d in g of . S 1 0 1 B ltE 5 S top counter n2 SPITE 6 3 co n n ect ringing tone ( £ 05 Wait for ] (_ s TJ Inter S 4 FITE 2 2 rupted Stop S top Stop sen d in g of sen d in g of sen ding of S 3 S 3 S 3 SPITE 6A Start t2 d isconnect ringing tone 3 s © D eactivate carrier 0 0 Idle ) 228 Rec. 586-1 APPENDIX II Connector S h eet 3 References 2 3 7 3 ,5 4 6 N ote 1 - Signal used to initiate power level control and switching call-in-progress (see Appendix VI) Rec. 586-1 229 APPENDIX II Sheet 4 Connector References 230 Rec. 586-1 APPENDIX III Sheet 1 Connector References StatioirS^ No available? I Start t, --[ti=3s 1 ' 01 Wait for f~00 A S 101 V Idle J S 101 Go to Stop ti calling > channel Activate ( o o \ \ carrier' I Idle J S 2 Start \ r counter y 4 n i .- 8 ni X - (0 2 Wait foA V sT ) , , | | ' | 'v Inter- S 3 ^ S 11 ^ / rupted Stop Stop \ . Stop Stop \ sending of y sending ofy sending ofy sending of S 2 / S 2 / S 2 s 2 y [ | . | ' | Stop \ Stop \ Stop 'N Stop \ counter y counter N counter N counter n i / ni / ni / 1, 2 , 3,4 k k k k Incoming procedure at ship (land-originated call) Rec. §86-1 231 APPENDIX III Sheet 2 Connector References 1 Connect ringing [ 0 3 Wait for ] V answer J Off hook S11 Inter 2rupted Disconnect Disconnect S 4 ringing ringing 2,4 Start counter - [ " Y ~ 3 n2 7 04 Wait for j ( S 3 off j )> S3°« 511 Erupted ^ n2 On hook Stop "N Stop Stop Stop sending ofy sending of y sending of sending of S 4 X S 4 X S 4 S 4 I • I Stop "N Stop N. Stop Stop counter y counter y counter counter n2 X n2 X n2 n2 2,4,3 Connect local loop 6 f Answered 3(x2) Inter On hook O sn IX rupted 3 d> 1,2,3 S 8 Disconnect Disconnect local loop _ local loop 2,4,7 Start rn3 counter '1=8 r»3 06 Wait for J ( 59 ) S 9 S 11 r>3 ' n4 = 2 232 Rec. 586-1 APPENDIX III Sheet 3 Connector References & Go to, new channel Start t2 t2 = 3 s 07 Wait for S 15 ) I I I I Inter- S 15 hook ^ S11 y rupted > * No 0 8 Wait / S 16 i- 16 \ S11 N o ^ s n3 — Sen n4 / off ^ s ti m e s ^ f ' ,0 Y e s, Stop sending of S 8 /S 12 Stop counter n3 1 0 Deactivate 2(x3) carrier 3 Go to calling channel ( S > Rec. 586-1 233. APPENDIX IV Sheet 1 Connector’ References t3 = Yet not defined Incoming procedure at MSC (ship-originated call) .234 Rec. 586-1 APPENDIX IV Sheet 2 Start \ r counter y ni = 8 ni / TT 05 Wait for\ S ? J ( \ / . I I f i ^ S 6 cn CO Stop \ Stop \ S t o p X sending ofX sending ofS sending ofS S 10X / S 10X / S 10X / I I sto p N . Stop "X Stop counter y counter y counter ni X ni X ni < S 7 SPITE 3 SPITE 3 Start counter ;,= s(£ X 5 ni > i ' (Z T w aiuoi\ I S 6 off J i \ ...... / i cn \ S 6 CM / off Stop "X Stop Stop sending of> sending of > sending of S 7 X S 7 / S 7 1 1 Stop X Stop "X Stop counter y counter y counter ni X ni X ni SPITE 12 SPITE 3 SPITE 3 firisn- d)4 5 \ analysis / ■' \ / I I I I SPITE cn 00 X Inter- \ SPITE ^ S P I T E 14 / rupted > 13, 15, X 16,17 / 18,19 A ctivateX interworkingX SPITE 3 SPITE 3 procedur§X (±)A 5 Rec. 586-1 APPENDIX IV Connector Rec. 586-1 APPENDIX IV S h eet 4 ices 6 9 2 4,3 7,8 9 7 3 2 8 6,2 8 1 - Signal used for initiating power level control and switching call in progress (see Appendix VI). Rec. 586-1 APPENDIX V Sheet 1 Connector References 2 1 1 Outgoing procedure at ship (ship-originated call) 238 Rec. 586-1 APPENDIX V Sheet 2 Connector References 1 1(x2)T9 Start t4 = 3 s 06 Wait for ( S 10X Stop \ Stop Stop N. Stop N . • Stop \ sending of sending o fy sending o fy sending of y sending of S 6 / S 6 / S 6 / S 6 / S 6 / 1 . 1 1 Stop Stop Stop N. Stop Stop counter counter y counter y counter y counter ni ni / m / m / Oi 3,4 Release Start t5 local loop (2X < b u . 08 Wait for S 7 off i i i i i S11 ^ S7off^ ) > h 2 o nk iS i52 ? \ / \/ rupted inter- ^ *■ Connect Release Stop t5 Stop ts Stop t 5 Stop t 5 speech path local loop Inform Stop ts 3,4 caller 5,3 Rec. 586-1 239 APPENDIX V Sheet 3 Connector References 5 3 4,6 = 3 s 7,5 4,6 7 240 Rec. 586-1 APPENDIX VI Sheet 1 Connector References Power level control and switching call in progress control at MSC Rec. 586-1 241 APPENDIX VI Sheet 2 Connector References 242 Rec. 587-1 RECOM M ENDATION 587-1 COAST STATION IDENTITIES AND INITIATION OF LOCATION REGISTRATION IN AN AUTOMATED VHF/UHF MARITIME MOBILE TELEPHONE SYSTEM (Question 23/8) (1982-1986) The CCIR, CONSIDERING (a) Recommendation 586 (Automated VHF/UHF maritime mobile telephone system); (b) that in accordance with Appendix 43 of the Radio Regulations (Geneva, 1979) and CCITT Recommenda tion E.210/F.120, coast station identities are formed as follows: 0 0 MID X6 X7 X8 X9 \ . . where the MID reflects the country in which the coast station is located and X6, X7, X8 and X9 are any Figure from 0 to 9; (c) that location registration procedures are defined, as those to be followed for a ship station identity to be entered in a location register of a maritime switching centre (MSC); (d) that location registration procedures are initiated by ship stations; (e) that up to 100 coastal areas may belong to one MID and no more than 100 coast stations need to be accommodated within one coastal area; (f) that each individual coast station must have a unique identity, UNANIMOUSLY RECOMMENDS 1. that for a given MID a coastal area be identified by the digits X6 X7; 2. that within one coastal area a coast station be identified by the digits X8 X9; 3. that the ship station initiates a location registration procedure when it detects a change in one or more of the digits of the sequence MID X6 X7 of the identity 0 0 MID X6 X7 X8 X9 belonging to the received coast station. Rec. 689 243 S. RECOMMENDATION 689* OPERATIONAL PROCEDURES FOR AN INTERNATIONAL MARITIME VHF RADIOTELEPHONE SYSTEM WITH AUTOMATIC FACILITIES BASED ON DSC SIGNALLING FORMAT ** (Question 73/8) (1990) The CCIR, CONSIDERING (a) . that an automated maritime VHF radiotelephone system would expedite the handling of traffic and increase the efficient use of the radio channels; (b) that international standardization is of great importance in the maritime mobile service; (c) that the existing public correspondence channels listed in Appendix 18 to the Radio Regulations are in widespread use by ships and coast stations in the maritime mobile service; (d) that no other VHF channels are available for the exclusive use of the maritime mobile service;' (e) that Articles 60 and 65 of the Radio Regulations do not permit coast stations to emit signals on idle VHF radiotelephone working channels; (f) that the Digital Selective Calling (DSC) system described in Recommendations 493 and 541 can be used for signalling over the radio path for an automatic system using a common VHF DSC channel; (g) that the existing Appendix 18 channels can be used in such an automatic system without impairing their use for manual operations from ships or coast stations, UNANIMOUSLY RECOMMENDS 1. that the operational procedures for ship-to:shore which are described in Annex I, be observed when operating an international radiotelephone system with automatic facilities based on the DSC signalling format, and using the public correspondence channels listed in Appendix 18 to the Radio Regulations; 2. that the same Appendix 18 channel can be used for both automatic and manual operation by the same coast station depending on the requirements of the ship stations; . 3. that the technical characteristics of the ship and coast station equipment should be in accordance with Annex II. ANNEX I OPERATIONAL PROCEDURES 1. Introduction 1 Appendix 1 illustrates the timing of the call set-up, calling and acknowledgement sequences described by these procedures. 2. Operational procedures on DSC calling channel 2.1 Ship station initiates call 2.1.1 The user aboard the ship (hereafter referred to as the user) composes the calling sequence on his DSC equipment as follows: — selects the format specifier 123 (automatic/semi-automatic service); — enters address (identification) of required VHF coast station; * The Director, CCIR, is invited to bring this Recommendation to the attention of CCITT. ** Coast stations may also use other procedures with automatic facilities based on DSC signalling format directly on VHF radiotelephone working channels. 244 Rec. 689 — selects the category routine (100); — (the ship station self-identification is entered automatically); — selects first telecommand 101 (duplex F3E/G3E) or 100 (simplex F3E/G3E) or 106 (Data) (see Note) and second telecommand as appropriate; — inserts subscriber number required (e.g. telephone number); — selects “end of sequence” signal “RQ”. Note — Duplex mode of operation should be used for data communications. 2.1.2 It is assumed that commercial equipment will be produced which simplifies the composition of the calling sequence. In practice the user should only need to key the VHF coast station address and the required subscriber number, all other information being inserted automatically. 2.1.3 The user selects the VHF DSC calling channel (channel 70 of Appendix 18 to the Radio Regulations) and initiates transmission of the sequence on the calling channel. In order to reduce the probability of call collisions, the DSC equipment should automatically inhibit transmission of this sequence until the calling channel is clear of any signal. 2.1.4 If the ship station does not receive an error-free acknowledgement from the called coast station (see § 2.2) within 5 s, the calling sequence should be automatically repeated. In an error-free acknowledge ment is still not received within a further 5 s then any further repetitions should be effected by manually initiating a new calling sequence. Such further repetitions to the same coast station should not, however, be initiated until at least 15 min has elapsed. 2.2 Coast station acknowledgement 2.2.1 If, on receipt of an error-free calling sequence, the coast station can comply immediately with the call request, then it should immediately radiate an “engaged channel” signal on the coast station transmit frequency of the appropriate working channel. 2.2.2 The coast station should, within 3 s of receipt of the calling sequence, initiate the transmission of an acknowledgement sequence on the DSC calling channel. The coast station equipment should also automatically inhibit transmission of the acknowledgement until the calling channel is clear. 2.2.2.1 If the coast station can comply immediately with the call request the acknowledgement sequence should contain the same information as in the call request with the following exceptions: — the address will be that of the iship; — the self-identification will be that of the coast station; — the working channel number will be included; — the “end of sequence” signal will be “BQ”. 2:2.2.2 If the coast station cannot comply immediately with the call request due to the appropriate working channel(s) being busy, then the acknowledgement sequence should be as in § 2.2.2.1 except that the first and second telecommands will be 104 (unable to comply) and 102 (busy) respectively, no subscriber number should be included and three symbols No. 126 should be included in the channel information field. 2.2.2.3 If the coast station cannot comply for other reasons, the acknowledgement sequence should be as in § 2.2.2.2, except that the second telecommand signal should be one of symbol numbers 100-109 as appropriate. 2.2.3 The ship station, on receipt of an error-free acknowledgement in accordance with § 2.2.2.1 (ability to comply), should, within 5 s of receipt, change to the working channel indicated in the acknowledgement and transmit, on that working channel, a carrier for a minimum period of 2 s. Fully automated ship station equipment should, within that transmission, transmit a DSC call which is identical to the initial call (see § 2.1.1) except that the “end of sequence” signal should be 127 (see Note). Note — In some regional applications, ships do not transmit DSC signals on the working channels. Equipment on ships sailing beyond these regional applications and participating in the automated service, should be able to comply with the requirements for the fully automated service. Rec. 689 245 2.2.4 If the ship station receives an error-free acknowledgement in accordance with § 2.2.22 indicating “unable to comply — busy” then, if the coast station operates the “ring-back” procedure in accordance with § 3.2 and the user still requires the call connection, the ship station should continue to monitor the DSC calling channel for any calls from the coast station. 2.2.5 The ship station, on receipt of an acknowledgement indicating “unable to comply” in accordance with § 2.2.2.3 (or, if the coast station does not operate the “ring-back” procedure (§ 3.2),in accordance with § 2.2.2.2), should, if an automatic connection is still required, initiate an appropriate new call in accordance with § 2.1. 2.2.6 If the coast station transmitted an acknowledgement indicating “unable to comply” in accordance with § 2.2.2.3 (or, if the coast station does not operate the “ring-back” procedure (§ 3.2),in accordance with § 2.2.2.2), then it should take no further action with respect to the call request. 3. Procedures subsequent to the exchange of initial DSC calls 3.1 Mandatory procedure 3.1.1 If the coast station transmitted an acknowledgement indicating “able to comply” (§ 2.2.2.1) then, if , a DSC call (§ 2.2.3) containing the same self-identification as that of the calling ship is detected on the coast station receive frequency of the working channel, the coast station should immediately start to dial the required subscriber number (see Note § 3.1.2). 3.1.2 If a further call identical to the original calling sequence is received from the ship station within 16 s of receipt of the original calling sequence (see § 2.1.1) then the coast station should repeat the acknowledgement (§ 2.2.2.1). If a DSC call is in accordance with § 3.1.1 (Note) is not detected within this 16 s period then the coast station should remove the “engaged channel” signal. Note — Some coast stations detect only the presence of a carrier at this stage. In areas of high traffic density, carrier detection may not ensure that the calling ship has transferred to the working channel and should be avoided where practicable. 3.2 Optional “ring-back” procedure The following additional sequence will tend to reduce repetitive ship calling and provide a better service to the ship: 3.2.1 If the coast station transmitted an “unable to comply — busy” acknowledgement (see § 22.2.2) then the ship’s identification and required subscriber number should be stored until an appropriate working channel becomes available. This information should be retained for a period of 15 min. 3.2.2 If an appropriate working channel becomes available within the 15 min period, the coast station should immediately radiate an ’’engaged channel” signal on the coast station transmit frequency of that working channel and initiate a DSC call on the DSC calling channel to the ship station with the same format as the acknowledgement (see § 2.2.2.1) except that the “end of sequence” should be “RQ”. If no appropriate working channel becomes available within this 15 min period then the information should be cleared and no further action taken by the coast station. 3.2.3 If an acknowledgement of the above call is not received from the ship station (see § 3.2.4) within 5 s then the coast station should repeat the call. If there is no acknowledgement to this second call then the ship’s call details should be cleared and the “engaged channel” signal removed. 3.2.4 The ship station, on receipt of such a calling sequence (§ 3.2.2) should, if the call connection is still required, automatically initiate an acknowledgement within 2 s on the calling channel (the acknowledge ment being transmitted only when the channel is clear). This acknowledgement should be identical to the received calling sequence except that the address should be that of the coast station, the self-identification should be that of the ship station and the “end of sequence” should be “BQ”. 3.2.5 The ship station should then continue to listen to the calling channel for a further 5 s, then change to the working channel and transmit a carrier and DSC call as described in § 2.2.3. If a further calling sequence is received within this 5 s period, the acknowledgement should be repeated. 3.2.6 The coast station, after receipt of an acknowledgement from the ship station, should, when a DSC call in accordance with § 3.1.1 (see Note § 3.1.2) is detected on this working channel, immediately start to dial the subscriber number. 246 Rec. 689 3.2.7 If, after a period of 15.5 min a ship has not received a call as indicated in § 3.2.2 then, if the call connection is still required, a new call should be manually initiated in accordance with § 2.1.1. 4. Call connection 4.1 Once the coast station begins dialling the subscriber number it should connect the line circuit to the radio path. Timing of the call for billing purposes should commence after the subscriber answers, i.e. “off-hook” condition detected. The call connection is now retained and the user should commence communication as soon as the subscriber answers. For a ship working on a duplex basis (see Note) the carrier must be transmitted for the total duration of the call. For a ship not working on a duplex basis the carrier must be activated at least once every 45 s. Such activation, when it does not occur naturally (due to the ship transmitting) should preferably be automatic. If automatic activation is not provided then means could be provided to timely alert the user that carrier activation is necessary. Note — Ships capable of working duplex but using a semi-duplex operation should use the telecommand signal 100. 4.2 If the called subscriber does not answer within a period of 1 min from completion of dialling, then the call should be considered as not started and the coast station should clear the circuit by disconnecting the line and removing his carrier. The user, on hearing the ringing tones stop or hearing anything other than “ringing” tones (e.g. engaged, number unobtainable, etc.) should refrain from any further transmissions on the working channel. If a further call is required, the user should initiate a new call on the DSC calling channel. The ship’s equipment should prevent the transmission of a new call on the DSC calling channel until at least 5 s have elapsed after clearance to prevent malfunction of the coast station “call completion due to ship station clearance” procedure (see § 4.4.1, 4.4.2 and 5.5). 4.3 If a further call is attempted from the same ship within the “time-out period” (semi-duplex operation, see § 4.4.2) the coast station may use the information derived from the call to disconnect the previously allocated working channel. 4.4 If, during any period of the call, the coast station equipment detects the absence of the ship’s carrier, the following procedures apply: 4.4.1 If the first telecommand indicated duplex operation and the coast station equipment detects the absence of the ship’s carrier for a period greater than 5 s, then the call should be considered to be complete. 4.4.2 If the first telecommand indicated simplex operation and the coast station equipment detects the absence of the ship’s carrier for a period greater than 45 s, then the call should be considered to be complete. 4.5 If during any period of the call, a fully automated ship station equipment detects the absence of the coast station’s carrier for a period greater than 5 s, the call should be considered to be complete. 5. Call completion,(Note § 2.2.3 applies to § 5.1 to 5.4) 5.1 When the ship station wishes to terminate the call connection to the PSTN, it transmits an “end of call” DSC call on the working channel and removes the carrier. The form of this call should be the same as that described in § 2.1.1 except that the first telecommand should be 105 (end of call) and the second telecommand should be 126. 5.2 On receipt for that call (see Note), if it contains the same self-identification as, that of the calling ship, the landline is disconnected, the call timing is stopped, the coast station transmits a DSC acknowledgement on the working channel within 1 s of receipt and removes its carrier from the working channel. The format of that acknowledgement should be the same as that described in § 5.1 except that the “end of sequence” signal should be BQ and: — the chargeable duration of the call should be inserted in the “frequency/channel” field by coding the three characters as hours, minutes, seconds, e.g. a chargeable duration of 6 min and 50 s would be coded as 00 06 50; Rec. 689 247 — if the chargeable duration of the call is not available then the “frequency/channel” field should contain three symbols 126. Note — Some coast stations do not recognize this “end of call” DSC call or transmit the above acknowledgement but rely solely on the procedures described in § 5.5. 5.3 If the coast station receives a second “end of call” DSC from the ship station within 4 s then it should repeat the procedure given in § 5.2. 5.4 If the ship station does not receive an “end of call acknowledgement” within 2 s then it should automatically repeat the “end of call”, then after a further 2 s or after receipt of an “end of call acknowledge ment” (whichever occurs first) it should consider the call to be complete and remove the carrier from the working channel. 5.5 If the coast station does not receive the “end of call” as described in § 5.2 then the call will be considered to be complete when the “on-hook” condition is detected from the PSTN or if no reply within 1 min or loss of ship’s carrier for more than 5 s (duplex) or 45 s (simplex) is detected (see § 4.2 to 4.4.2). When this indication is registered at the coast station the following action should take place: — call timing is stopped; — the line is cleared and disconnected from the radio circuit; — the coast station transmits an “end of call” DSC call whose format is the same as that of the acknowledge ment described in § 5.2 except that the “end of sequence” signal should be 127; — the coast station’s carrier is removed from the working channel. The radio channel is now free to handle other traffic. 5.6 If the ship station detects the absence of the coast station’s carrier for a period greater than 5 s, then it should cease to transmit on the working channel. If further calls are required by the ship then a new call should be initiated on the DSC calling channel. 248 Rec. 689 APPENDIX I TIMING DIAGRAM OF CALL SET-UP SEQUENCES Coast station able to comply Coast station unable to comply (busy) Time Ship Coast station Ship Coast station (s) 0 InitialecaU (§2.1.3) Initiate call (§ 2.1.3) 1 Receive call and radiate Receive call engaged channel signal (§2.2.1) 2 3 4 Initiate acknowledgement Initiate acknowledgement (able) (§ 2 .2 .2 . 1 ) (unable) (§ 2 .2 .2 .2 ) and store ship ID and telephone number (§3.2.1) 5 Receive acknowledgement Receive acknowledgement (§ 2.2.3) { or initiate 2nd and continue monitoring call (§ 2.1.4)} DSC channel (§ 2.2.4) { or initiate 2nd call (§2.1.4)} 6 {Receive 2nd call (and {Receive 2nd call} radiate engaged channel signal if 1 st call not received-§ 2 .2 . 1 )} 7 8 9 {Initiate acknowledgement {Initiate acknowledgement due to 2 nd call (§3.1.2 and due to 2nd call (§ 3.1.2 and §2.2.2.!)} § 2.2.2.2)} 10 Transmit carrier and DSC {Receive «2nd» call on working channel acknowledgement and continue (§ 2.2.3) {or receive «2nd» monitoring DSC channel acknowledgement} (§ 2 .2 .4 )} 11 ...... Recognize DSC call then dial (§ 3.1.1) 12 13 14 15 {If not already done so, transmit carrier and DSC call on working channel (§ 2 .2 .3 )} * This timing diagram is only applicable to fully automated ship station equipment that operate with coast stations employing DSC signalling on the working channels. Rec. 689 249 Coast station able to comply 'Coast station unable to comply (busy) S h ip Time Coast station S h ip Coast station (s) 16 {If not already done so, recognize DSC call then dial (§ 3 .1 .1 )} 17 {If no DSC call recognized, remove engaged channel signal and delete calling record (§ 3.1.2)} < = 15 min 4s : ...... If working channel available then radiate engaged channel signal on working channel and transmit DSC «ring-back» call (§ 3.2.2) 5 ...... Receive «ring-back» call 6 \ 7 ...... Transmit «ring-back» acknowledgement (§ 3.2.4) 8 ...... Receive «ring-back» acknowledgement. 9 . . .. . Initiate 2nd «ring-back» call (§ 3.2.3) 1 0 ...... {Receive 2 nd «ring-back» call} ' 1 1 12...... ; ...... Transmit carrier and DSC call on working channel {and transmit acknowledgement due to 2nd call} (§ 3.2.5) 13 Recognize DSC call then dial (§ 3.2.6) {and receive « 2 nd» «ring-back» acknowledgement} 14 15 16 17 {If not already done so, transmit carrier and DSC call on working channel due to 2nd call (§ 3.2.5)} 18 {If not already done so, recognize DSC call then dial (§ 3.2.6) or, if no DSC call and acknowledgement, remove engaged channel signals and clear call details (§ 3 .2 .3 )} Mote 1 -r- Timing diagram assumes I s between call initiation and reception and assumes maximum timing between calls and acknowledgements. N ote 2 — Sequences in parentheses only applicable if repeat calls or acknowledgements are necessary. 250 Rec. 689 ANNEX II TECHNICAL CHARACTERISTICS 1. Ship station 1.1 The DSC equipment should meet the VHF technical characteristics detailed in Recommendation 493, Annexes I or II. This equipment need not necessarily provide all combinations of codes, e.g. it may be simplified DSC equipment (with no distress functions), but it must provide all the necessary formats for automatic/semi automatic VHF DSC signalling. 1.2 The VHF transceiver should be capable of operating on all public correspondence radio channels listed in Appendix 18 of the Radio Regulations and on the DSC calling channel and be capable of automatic channel selection and carrier transmission under control of the DSC equipment. 1.3 The equipment should be capable of sensing the presence of a signal on the DSC calling channel.* 1.4 After initiation of a DSC call, the equipment should be capable of automatic prevention of the transmission of that call, when the calling channel is occupied by calls. * 1.5 The equipment should be capable of operating in accordance with the operational procedures described in this Recommendation. 2. Coast station 2.1 The DSC equipment should meet the VHF technical characteristics detailed in Recommendation 493, Annex I. The installation should be capable of receiving and transmitting all types of VHF DSC calls on the DCS calling channel. 2.2 The VHF installation should be capable of operating in full duplex mode on the coast station’s designated public correspondence working channels and in simplex mode on the DSC calling channel. 2.3 After initiation of a DSC call, the equipment should be capable of automatic prevention of the transmission of that call when the calling channel is occupied by calls. * 2.4 The coast station equipment should be capable of detecting the presence of a DSC call on a working channel and also the line subscriber’s “off-hook” and ”on-hook” conditions. 2.5 The coast station should be capable of radiating an “engaged channel” signal on any of its working channels which should be dissimilar from any present line signalling tones. 2.6 The equipment should be capable of operating in accordance with the operational procedures described in this Recommendation. See Appendix 19 to the Radio Regulations. Rec. 628-1 251 SECTION 8D: RADIODETERMINATION, GLOBAL MARITIME DISTRESS AND SAFETY SYSTEM AND RELATED SUBJECTS RECOMMENDATION 628-1 * TECHNICAL CHARACTERISTICS FOR SEARCH AND RESCUE RADAR TRANSPONDERS (Questions 28/8 and 45/8) (1986-1990) The CCIR, CONSIDERING (a) that Regulations III/6.2.2 and IV/7.1.3 of the 1988 Amendments to the International Convention for the Safety of Life at Sea, 1974 (SOLAS) require the carriage of radar transponders operating in the 9 GHz frequency band for locating the ship when it is in distress at sea or its survival craft; (b) that such radar transponders may also be used by ships not subject to the 1974 SOLAS Convention; some of these radar transponders may be installed with a float-free release and activation arrangement or with a float-free EPIRB or float-free satellite EPIRB; (c) that Regulations V/12(g) and (h) of the 1988 Amendments to the 1974 SOLAS Convention prescribe requirements, for passenger ships irrespective of size and cargo ships of 300 tons gross tonnage and upwards to carry a radar installation or of 10 000 tons gross tonnage and upwards, two radar installations; from 1 February 1995 the radar installation of at least one of the radar installations shall be capable of operating in the 9 GHz frequency band; ' (d) that IMO has adopted a recommendation on performance standards for survival craft radar transponders for use in search and rescue operations (Resolution A.604(15)); (e) that location is part of the basic requirements for the GMDSS; (f) that a locating system would be more effective if the radar transponder was in conformity with internationally agreed technical and operating characteristics, UNANIMOUSLY RECOMMENDS that the technical characteristics of search and rescue radar transponders operating in the frequency range 9200-9500 MHz should be in accordance with Annex I to this Recommendation; ANNEX I MINIMUM TECHNICAL CHARACTERISTICS FOR SEARCH AND RESCUE RADAR TRANSPONDERS OPERATING OVER THE BAND 9200-9500 MHz 1. Frequency: 9200-9500 MHz. 2. Polarization: horizontal. 3. Sweep rate: 5 ps per 200 MHz, nominal. 4. The response signal should consist of 12 sweeps. * The Director, CCIR, is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO), the International Civil Aviation Organization (ICAO), and the International Association of . Lighthouse Authorities (IALA). 252 Rec. 628-1 5. Form of sweep: sawtooth, forward sweep time: 7.5 ps ± 1 ps, return sweep time: 0.4 ps ±0.1 ps. The response should commence with a return sweep. 6. Pulse emission: 100 ps nominal. 7. e.i.r.p.: not less than 400 mW (equivalent to +26 dBm). 8. Effective receiver sensitivity: better than -50 dBm (equivalent to 0.1 mW/m2) (see Note 1). 9. Duration of operation: 96 hours in stand-by condition followed by 8 hours of transponder transmissions while being continuously interrogated with a pulse repetition frequency of 1 kHz. 10. Temperature range; ambient: -20°Cto + 55 °C, stowage: -30°Cto +65 °C. 11. Recovery time following excitation: 10 ps or less. 12. Effective antenna height: > 1 m (see Note 2). 13. Delay between receipt of radar signal and start of transmission : 0.5 ps or less. 14. Antenna vertical beam width: at least ±12.5° relative to the radar transponders horizontal plane. 15. Antenna azimuthal beamwidth: omnidirectional within ± 2 dB. Note 1 — Effective receiver sensitivity includes antenna gain. Note 2 — This effective antenna height is applicable for equipment required by Regulations III 16.2.2 and IV 7.1.3 of the 1988 Amendments to the 1974 SOLAS Convention. Rec. 629 253 RECOMMENDATION 629* USE FOR THE RADIONAVIGATION SERVICE OF THE FREQUENCY BANDS 2900-3100 MHz, 5470-5650 MHz, 9200-9300 MHz, 9300-9500 MHz AND 9500-9800 MHz (Question 63/8) v (1986) The CCIR, CONSIDERING (a) Resolution No. 600 of the World Administrative Radio Conference (Geneva, 1979); (b) that compatibility between shipborne radars and radar beacons (racons) in the radionavigation service is essential to assure safety of marine navigation; (c) that to be compatible, racons must operate in the frequency bands used by shipborne radars; (d) that most navigational shipborne radars operate in the bands 9320-950Q and 2920-3100 MHz. Only a small number of these types of radars operate in the band 5470-5650 MHz, and fewer still, if any, in the band 9500-9800 MHz; (e) that many airborne navigational radars operate in the 9320-9500 MHz band; (f) that racons presently operate in the bands 9300-9500 MHz, and in certain cases, 2900-3100 MHz; (g) that aeronautical radar beacons operate in the 9300-9320 MHz band; (h) that certain radar transponders devices operating in the bands used by these radars can be confused with a racon, thus creating the possibility of a hazard to navigation; (j) that other radar transponders could in certain circumstances aid in safety of navigation; (k) that radar transponders using user selectable techniques would not be displayed on normal shipborne radars, and thus should not be confused with a racon; (I) that radar transponders used for search and rescue purposes have a unique identification code which should prevent their being confused with a racon; (m) that the Radio Regulations restrict navigational shipborne radars from operating in the bands 2900-2920 and 9300-9320 MHz in order to protect fixed frequency racons in the maritime radionavigation service; (n) that the Radio Regulations restrict shipborne transponders from using the bands 2900-2930 MHz, 2950-3100 MHz, 5480-5650 MHz and 9200-9280 MHz; (o) , that because of radar antenna squint angle, fixed frequency racons or transponders will not come into general use in the maritime radionavigation service, UNANIMOUSLY RECOMMENDS 1. that designers of shipborne radars in the maritime radionavigation service ensure, to the extent practicable, compatibility with racons used by administrations for safety of navigation purposes; 2. that shipborne conventional pulse radars in the maritime radionavigation service preferably should not operate in the band 9500-9800 MHz; * The Director, CCIR, is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO), the International Civil Aviation Organization (ICAO) and the International Association of Lighthouse Authorities (IALA). 254 Rec. 629 3. that it is desirable not to exclude shipborne radars in the maritime radionavigation service from using the band 2900-2920 MHz; 4. that the effects of the maritime use by shipborne radars of the 9300-9320 MHz band on the aeronautical radionavigational service be urgently studied; 5. that special care be taken to prevent the response from transponders which operate in the bands 2900-3100 MHz, 9200-9300 MHz and 9300-9500 MHz from causing harmful interference to shipborne and airborpe radars or from being confused with the response from radar beacons; 6. that administrations reconsider the existing restrictions on the use of shipborne transponders in the band 2900-2930 MHz, 2950-3100 MHz, 5480-5650 MHz and 9200-9280 MHz to determine if there are technical or operational reasons for these restrictions to be continued. Rec. 439-3 255 RECOMMENDATION 439-3* EMERGENCY POSITION-INDICATING RADIO BEACONS OPERATING AT THE FREQUENCY 2182 kHz (Question 31/8) (1966-1974-1978-1982) The CCIR, CONSIDERING (a) Recommendation No. 48 of the International Conference on Safety of Life at Sea, London, 1960; (b) that Radio Regulations, Article 41, § 1 lays down the purpose and use of emergency position-indicating radio beacons (EPIRB) signals; (c) that all passenger ships and cargo ships of 300 gross tonnage and upwards are required to keep continuous watch at the frequency 2182 kHz by the International Convention for the Safety of Life at Sea (1974); (d) that some administrations require other classes of ship to keep continuous watch at the frequency 2182 kHz; (e) that in accordance with Regulation 10, Chapter IV, of the International Convention for the Safety of Life at Sea (1974), a radiotelephone distress frequency watch receiver preset to this frequency shall be provided. The receiver shall be provided with a filtering unit or a device to silence the loudspeaker, if the latter is located on the bridge, in the absence of a radiotelephone alarm signal. The device shall be capable of being easily switched in and out and may be used when, in the opinion of the master, conditions are such that maintenance of the listening watch would interfere with the safe navigation of the ship; (f) that IMO Resolution A383 (X) provides that the distress watch receiver fitted with a muting device should respond to the radiotelephone alarm and the vital navigation warning signal. In addition, the muting device may also respond to a keyed emission modulated only by a 1300 Hz tone, however, where such a facility is not provided the mute will not be lifted on distress watch receivers by EPIRBs transmitting such signals; (g) that the definition of the duty cycle of the 1300 Hz tone modulated emission (Radio Regulation No. 3257) is suitable for reliable operation of muted watch receivers only if there are specific national provisions; (h) that the Radio Regulations, Appendix 37 defines EPIRBs operating at the frequency 2182 kHz as type “L” , or type “H”, according to their output power; (j) that it is desirable that both types of EPIRB perform an alerting function; (k) that the signal emitted by an EPIRB should be suitable for reception by a watchkeeping receiver with a loudspeaker; (I) that the signal emitted by an EPIRB should, as far as practicable, be clearly distinguishable from the radiotelephone alarm signal transmitted by ships still afloat or by portable radio apparatus; (m) that the signal emitted by an EPIRB should not create harmful interference to other distress calls and messages; (n) that the type and sequence of the signal to be transmitted by an EPIRB should facilitate homing by ships as well as by search and rescue (SAR) aircraft, taking into account their different speeds; (o) that in the interests of high reliability and minimum expense the electronic and mechanical design of an EPIRB and especially of its keying device should be as simple as possible, ' * The Director, CCIR, is requested to transmit this Recommendation to the International Maritime Organization (IMO), the International Civil Aviation Organization (ICAO) and to the General Secretariat of the ITU. 256 Rec. 439-3 UNANIMOUSLY RECOMMENDS 1. that according to the provisions of Appendix 37* (paragraphs a), b) and c)) to the Radio Regulations: 1.1 “the power radiated by low-power EPIRBs (Type “L”) shall be of a value necessary to produce at a distance of 30 nautical miles at sea level a field strength equal to or less than 10 micro volts per metre, with an initial field strength of at least 2.5 micro volts per metre; 1.2 the power radiated by high-power EPIRBs (Type “H”) shall be of a value necessary to produce at a distance of 30 nautical miles at sea level a field strength greater than 10 micro volts per metre; 1.3 after a period of 48 h continuous operation the radiated power shall not be less than 20% of the initial power;” 2. that, noting the provisions of Article 41* (Nos. 3256 to 3258) and of Appendix 37 (paragraph e) of the Radio Regulations: 2.1 the keying signal for EPIRBs should consist of: — the radiotelephone alarm signal with a keying cycle which consists of the keying signal for between thirty and fifty seconds followed by the Morse letter B and/or the call sign of the ship to which the radio beacon belongs transmitted by keying a carrier modulated by a tone of either 1300 Hz or 2200 Hz, followed by a period of silence of between thirty and sixty seconds; — a keyed emission modulated by a tone of 1300 Hz having a period of emission of 1.0 to 1.2 s and a period of silence (carrier suppressed) of 1.0 to 1.2 s; 2.2 “the audio-frequency tolerance of emissions are: ± 20 Hz for the frequency of 1300 Hz ± 35 Hz for the frequency of 2200 Hz;” 2.3 that the EPIRBs should be capable of double-sideband or single-sideband full carrier emissions, with a depth of modulation between 30 and 90%; 3. that the keying cycles may be interrupted for the transmission of information relating to the distress incident; 4. that the EPIRBs should be designed for the following temperature ranges: — when stowed, at least — 20 °C to +55 °C; — when operated in the open air, at least —10 °C to +45.°C; — when operating afloat, at least — 3 °C to +35 °C. Note. — Exceptionally for EPIRBs carried by ships operating in limited areas only, other temperature ranges may, due to special conditions in such areas, be more appropriate. 5. that if the EPIRBs are designed to come into operation automatically when floating, then overriding facilities should be provided to enable them to be switched on manually. All EPIRBs should be capable of being switched off manually; 6. that when primary batteries are used as a source of power for EPIRBs, arrangements should be made for the equipment to be labelled to indicate the date by which the batteries should be replaced; 7. that the mechanical design of EPIRBs should be such that they are capable of continuous operation, under all sea states, humidity and change of temperature likely to be experienced at sea and should take into consideration that such EPIRBs might need to be small, lightweight, floatable, water-tight and shock-resistant, dependent upon the operational requirements for the EPIRB. Note by the CCIR Secretariat. — Article 41 and Appendix 37 to the Radio Regulations have been modified by the World Administrative Radio Conference for Mobile Services, Geneva, 1983. Rec. 690 257 RECOMMENDATION 690* TRANSMISSION CHARACTERISTICS OF EMERGENCY POSITION- INDICATING RADIO BEACONS (EPIRBs) OPERATING ON CARRIER FREQUENCIES OF 121.5 MHz AND 243 MHz (Question 31/8) (1990) The CCIR, CONSIDERING (a) that Radio Regulations, Article 41 § 2.(1) defines the purpose of emergency position-indicating radio beacon (EPIRB) signals; (b) that Radio Regulations, Article 41, § l.b) and § 4.(2) require that EPIRB signals operating on carrier frequencies of 121.5 MHz and 243 MHz be in accordance with those specified in Appendix 37A; (c) that additional technical and operating characteristics for 121.5/243 MHz EPIRBs in the aeronautical service are specified in Annex 10 to the Convention on International Civil Aviation, Vol. I; (d) that Recommendation No. 604 (Rev. MOB-87) of the World Administrative Radio Conference for Mobile Services (Geneva, 1987) recognizes that for EPIRBs operating on carrier frequencies of 121.5 MHz and 243 MHz, there is a need to improve their function of being detected and located by satellite systems; (e) that Resolution No. 601 (Rev. MOB-87) of the World Administrative Radio Conference for Mobile Services (Geneva, 1987) resolves that administrations authorizing the use of EPIRBs operating on carrier frequencies of 121.5 MHz and 243 MHz should ensure that such EPIRBs comply with relevant CCIR Recommen dations, standards and recommended practices of ICAO; (f) the information available on the detectability by the COSPAS-SARSAT distress alerting and locating satellite system of 121.5/243 MHz EPIRB signals with a variety of spectral outputs, UNANIMOUSLY RECOMMENDS that emissions of emergency position-indicating radio beacons operating on the carrier frequencies of 121.5 MHz and 243 MHz should include a clearly defined carrier frequency distinct from the modulation sideband components; in particular, at least 30% of the total power emitted during any transmission cycle with or without modulation should be contained within: — ± 30 Hz of thfe carrier frequency on 121.5 MHz, — ± 60 Hz of the carrier frequency bn 243,0 MHz. Additionally, if the type of emission is changed during transmission, the carrier frequency should not shift more than: — ±30 Hz from the carrier frequency on 121.5 MHz, — ± 60 Hz from the carrier frequency on 243.0 MHz. * The Director, CCIR, is requested to bring this Recommendation to the attention of the International Civil Aviation Organization (ICAO), the International Maritime Organization (IMO), and the COSPAS-SARSAT Secretariat. 258 Rec. 693 RECOMMENDATION 693* TECHNICAL CHARACTERISTICS OF VHF EMERGENCY POSITION-INDICATING RADIO BEACONS USING DIGITAL SELECTIVE CALLING (DSC VHF EPIRB) (1990) The CCIR, CONSIDERING (a) that the alerting and locating functions are parts of the basic requirements of the GMDSS; (b) that chapter IV of the 1988 Amendments to the International Convention for the Safety of Life at Sea (SOLAS), 1974, permits the carriage of a DSC VHF EPIRB in sea area A1 ** in lieu of a satellite EPIRB; (c) that the characteristics of the digital selective calling system are given in Recommendation 493; (d) that the characteristics of a search and rescue radar transponder (SART) for locating purposes are given in Recommendation 628, UNANIMOUSLY RECOMMENDS that the technical characteristics of DSC VHF EPIRBs should be in accordance with Annex I to this Recommendation and with Recommendation 493. ANNEX I MINIMUM TECHNICAL CHARACTERISTICS OF DSC VHF EPIRBs 1. General DSC VHF EPIRBs should be capable of transmitting distress alerts by digital selective calling and of providing a locating or homing facility. To meet the locating requirements of the GMDSS, Regulation IV/8.3.1 of the 1974 SOLAS Convention requires that a SART (see Recommendation 628) be used for this function. The EPIRB should be provided with a battery of sufficient capacity to enable it to operate for a period of at least 48 hours. The EPIRB should be designed to operate under the following environmental conditions: — ambient temperatures of — 20 °C to +55 °C, — icing, — relative wind speeds up to 100 knots, — after stowage at temperatures between — 30 ° C and + 65 ° C, 2. Alerting transmissions The alerting signals should be transmitted on the frequency 156.525 MHz using G2B class of emission. The frequency tolerance should not exceed 10 parts per million. The necessary bandwidth should be less than 16 kHz. The emission should be vertically polarized. The antenna should be omnidirectional in the azimuthal plane and sufficiently high to ensure reception of the transmission at the maximum range of the A1 sea area. The output power should be at least 100 mW***. * The Director of the CCIR is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO). ** “Sea area A l” means an area within the radiotelephone coverage of at least one VHF coast station in which continuous DSC alerting is available, as may be defined by a contracting government to the 1974 SOLAS Convention. *** The output power required to carry a ship-to-shore alert at the maximum range of the Al sea area should be at least 6 W with an appropriate antenna height above sea level. Rec. 693 259 DSC message format and transmission sequence The technical characteristics for the DSC message should be in accordance with the sequence for the “distress call” specified in Recommendation 493. The “nature of distress” indication should be “EPIRB emission” (symbol No. 112). The “distress coordinates” and “time” information need not be included. In this case the digit 9 repeated 10 times and the digit 8 repeated four times should be included, respectively, as specified in Recommenda tion 493. The “type of subsequent communication” indication should be “no information” (symbol No. 126) which indicates that no subsequent communications will follow. The alerting signals should be transmitted in bursts. Each burst should consist of five successive DSC sequences with the (N + l)th burst of transmission being made with an interval T„ after the (N)th burst as given in Fig. 1, where: Tn = (240 + lOiV) s (± 5%) and N — 0, 1, 2, 3, ... etc. /Vth burst (A/ + l)th bur§t 5 sequences 5 sequences T„ FIGURE 1 260 Rec. 487 RECOMMENDATION 487* USE OF RADIO-BEACON STATIONS FOR COMMUNICATIONS (1974) The CCIR, CONSIDERING (a) Report 581 in answer to Question 15/8 on the use of radio-beacon stations for communications; (b) the contents of Annex 10 to the Chicago Convention on International Civil Aviation, 3rd edition (July, 1972) Vol. I, Part I, § 3.4.6; (c) that, although the International Civil Aviation Organization (ICAO) does not preclude the use of modulation for communications purposes on radio beacons, there are at present no operational requirements in the ICAO Regional Plans; (d) that reliable performance of airborne automatic direction-finding equipment (ADF) may be seriously prejudiced if the beacon emission contains modulation by an audio frequency equal or close to the loop switching frequency or its second harmonic; (e) that aeronautical automatic direction-finding equipment now used in modern high speed jet transport aircraft increasingly employs phase-locked loop local oscillator techniques, which are severely affected by frequency shift keying of the carrier frequency; (f) thaUin some areas maritime beacons are very numerous and have of necessity to be grouped, and operate on a time sharing basis; (g) that there may be advantages for some users in the transmission of weather and other information as a secondary modulation of radio-beacon emissions and that some administrations are successfully using such services with A3E emissions, UNANIMOUSLY RECOMMENDS 1. that for radio beacons in the aeronautical radionavigation service any modulation additional to that necessary to provide identification shall be such that airborne automatic direction finder performance is not unacceptably degraded; (see ICAO Annex 10 to the Chicago Convention on International Civil Aviation, 3rd edition, (July, 1972) Vol. I, Part I, § 3.4.6); 2. that in suitable areas, i.e. where inter-beacon interference can be avoided, use could be made of radio beacons in the maritime radionavigation service for other purposes. In such cases, the methods of modulation used should be such that marine direction-finders can continue to be used when signals are emitted other than those proper to the radio beacon itself; 3. that any such additional modulation should not affect the frequency of the carrier. Note. — The Director, CCIR, is requested to bring this Recommendation to the attention of ICAO ,and the International Maritime Organization (IMO). This Recommendation terminates the study of Question 15-1/8, which has been deleted. Rec. 588 261 RECOMMENDATION 588 CHARACTERISTICS OF MARITIME RADIO BEACONS (REGION 1) (Question 58/8) ' (1982) The CCIR, CONSIDERING' (a) Recommendation No. 602 of the World Administrative Radio Conference, (Geneva, 1979); (b) that provisions aimed at preventing one radio beacon from causing harmful interference to another should be inserted in the Radio Regulations; (c) that it is nevertheless essential to fix frequency spacings with sufficient flexibility to allow for the existing technical facilities; (d) that these facilities will not require the maintenance in the future of as large a frequency spacing as that adopted for Region 1 in the Radio Regulations, UNANIMOUSLY RECOMMENDS 1. that frequency assignments to maritime radio beacons operating in the bands between 283.5 kHz and 335 kHz should also be determined, assuming that the radiated power is maintained at the necessary minimum value to attain the desired field strength at the service range, by the need to ensure an adequate geographical separation to avoid harmful interference between radio beacons operating on the same frequency and at the same time; 2. that frequency assignments to maritime radio beacons should be based on multiples of 100 Hz. The adjacent frequency spacing should be sufficient to prevent one radio beacon from causing harmful interference to another in the same geographical area; 3. that the siting of maritime radio beacons should be based on regional or sub-regional arrangements; 4. that Administrations of Regions 2 and 3 should be invited to consider that arrangements should be made to ensure that frequency allocations are made on a compatible basis throughout the world. 262 Rec. 630 \ RECOMMENDATION 630* MAIN CHARACTERISTICS OF TWO FREQUENCY SHIPBORNE INTERROGATOR TRANSPONDERS (SIT) (Question 28/8) (1986) The CCIR, CONSIDERING / (a) that the use of a secondary radar system would increase the ship’s radar range and improve radar discrimination of vessels in the presence of interference; ■(b) that the use of a secondary radar system would make it possible to identify individual ships and to obtain navigational and other data from an interrogated vessel; (c) that the combined use of a secondary radar system and of an automatic radar plotting aid (ARPA) would enhance the efficiency of the latter by increasing the range, the noise immunity of the reply co-ordinate signal and absence of fluctuation in its amplitude; (d) that in view of CONSIDERINGs (a), (b), and (c), the use of a secondary radar system would help to improve the safety of shipping and the economics and efficiency of shipping operations; (e) that in the design, preference should be given to a system using two-frequency interrogation consisting of a SIT interrogating signal and a shipborne navigation radar sounding pulse in the 3 cm band; (f) that the operation mode and the main operating characteristics of the system, as well as the main technical characteristics of the SIT, should be co-ordinated internationally by the users to ensure the compatibility of equipment manufactured in different countries, UNANIMOUSLY RECOMMENDS that for the two-frequency SIT system operating in the 10 cm band and the 3 cm band, designed to ensure safe passage of ships and regulation of the movement of ships from a central point: — the operating modes should conform to Annex I, — the operating characteristics should conform to Annex II, — the technical characteristics should conform to Annex III. * The Director, CCIR, is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO) and the International Association of Lighthouse Authorities (IALA). Rec. 630 263 ANNEX I ■ , OPERATING MODES Interrogation R esp onse R eflection T ype o f Address C ontent Capacity D ata input w orking T ype L ocation A ll ships A ll ships P olar ship - ' > - Screen blip PPI radar co-ordinates screen Selective I Ship selected Ship station 9 digit number From continuous Figures Panel display by operator identity storage unit Selective II Ship selected H eading 3 decim al From ship direction Figures Panel display by operator digits and speed sensors or m anually Speed 2 decim al digits M anoeuvre 1 decim al digit Selective III-VI Ship selected Determined in 6 digit number From continuous Figures Panel display by operator development storage unit or o f system m anually N ote. — Blip on PPI radar screen is shown with all types of operation. 264 Rec. 630 ANNEX II MAIN OPERATING CHARACTERISTICS OF SECONDARY MARINE RADAR SYSTEM Parameter V alue R ange: Minimum (m) < 300 Maximum (raised antenna, height 15 m) (nautical miles) > 1 0 Resolution: In direction (at a radar antenna radiation pattern of width 1°) (degrees) < 3 In distance (m): — all ships operation < 200 — selective operation < 500 Distance of response signal from echo signal (m ) < 200 Error in determination of ship co-ordinates Not worse than radar error ANNEX III MAIN TECHNICAL CHARACTERISTICS OF SIT V alue Param eter 10-cm band 3-cm band A n tenn a: Polarization Vertical H orizontal Radiation pattern (degrees): In horizontal plane 360° 360° In vertical plane 40°-60° 40°-60° Transmitter: Carrier frequency (MHz) 2940 ± 2 Impulsive power (W) 100-200 - Length of pulse (ns) 100 ± 20 R eceiver: Sensitivity (dBW) Better than —115 Better than —72 Frequency band (MHz) 2930-2950 9320-9500 B it rate (M b it/s): Of interrogating signal 2 Of response signal 3.3 Interrogating signal lead time relative to associated radar sounding pulse (ps) 14 ±0.2 Rec. 589-1 265 RECOMMENDATION 589-1 * INTERFERENCE TO RADIONAVIGATION SERVICES FROM OTHER SERVICES IN THE BANDS BETWEEN 70 kHz AND 130 kHz (Question 33/8) (1982-1986) The CCIR, CONSIDERING (a) that radionavigation systems exist or are being implemented in the three Regions of the ITU; (b) that various services, including radionavigation systems, operate in frequency bands between 70 kHz and 130 kHz; '(c) that radionavigation being a safety service, all. practical means consistent with the Radio Regulations should be taken to prevent harmful interference to any radionavigation system; .(d) that users of phased pulsed radionavigation systems in the band 90-110 kHz receive no protection outside that band, yet may receive benefit from their signals outside the occupied bandwidth; (e) that in the band 90-110 kHz, different phased pulsed radionavigation systems may operate in adjacent areas, on the same assigned frequency and within the same occupied bandwidth, UNANIMOUSLY RECOMMENDS 1. that for CW-radionavigation systems in the frequency bands 70-90 kHz and 110-130 kHz the parameter to be used in planning, to avoid harmful interference, should be the protection ratio in terms of wanted to unwanted signals; 2. that the protection ratio, for CW-radionavigation systems with characteristics such as that of an existing system (see Report 915) that presently operates in the same bands, should be 15 dB within the receiver pas&band of ±7 Hz at 3 dB; 3. that information be exchanged between the authorities operating radionavigation systems in the band 90-110 kHz with those operating other systems in the band 70-130 kHz employing stable transmissions; 4. that administrations operating radionavigation systems in the band 90-110 kHz in adjacent areas coordi nate the technical characteristics of their individual systems in accordance with the Radio Regulations; 5. that within the band 90-110 kHz, the protection ratio for pulsed radionavigation systems with characteris tics such as that of an existing system (see Report 915) should be 15 dB in terms of wanted to unwanted emissions of other than pulsed radionavigation systems. * The Director, CCIR, is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO), the International Civil Aviation Organization (ICAO), the International Association of Lighthouse Authorities (IALA) and Study Group 7. 266 Rec. 631 RECOMMENDATION 631 USE OF HYPERBOLIC MARITIME RADIONAVIGATION SYSTEMS IN THE BAND 283.5-315 kHz (Question 58/8) (1986) The CCIR, CONSIDERING (a) that there could be operational advantages in radionavigation systems operating in the band 283.5-315 kHz providing automatic determination of position; (b) that Recommendation No. 2 of the Regional Administrative Conference for the Planning of the Maritime Radionavigation Service (Radiobeacons) in the European Maritime Area, Geneva, 1985, considered that a requirement for a phase measurement multi-frequency radionavigation system in the band 283.5-315 kHz had arisen and had invited the CCIR to continue to study the possibility of using radiobeacons in the hyperbolic mode; .(c) that Report 913 describes the technical characteristics of an existing phase measurement multi-frequency radionavigation system working in the hyperbolic mode, UNANIMOUSLY RECOMMENDS that the protection ratio for a hyperbolic phase measurement multi-frequency radionavigation system with characteristics such as an existing system (see Report 913) should be 20 dB within ±110 Hz of the centre frequency of the system. Rec. 691 267 RECOMMENDATION 691 * TECHNICAL CHARACTERISTICS AND COMPATIBILITY CRITERIA OF MARITIME RADIOLOCATION SYSTEMS OPERATING IN THE MEDIUM FREQUENCY BAND AND USING SPREAD-SPECTRUM TECHNIQUES ' (1990) The CCIR, CONSIDERING (a) Question 75/8 on maritime radiolocation systems operating in the medium frequency band and using spread-spectrum techniques; • . ' (b) the results of experiments carried out in certain countries on the application of spread-spectrum techniques to maritime radiolocation (Report 1041); (c) that, in the absence of interference, the quality of radiocommunication services in the MF band is limited by atmospheric noise; ■(d) that emissions intended for maritime radiolocation should not cause harmful interference to other radiocommunication services; (e) that development of the use of spread-spectrum techniques without control of the spectral power density level or without coordination might increase the noise level, UNANIMOUSLY RECOMMENDS 1. that the signals produced by transmitting stations using spread-spectrum techniques in the MF band and intended for the maritime radiolocation service should have the following characteristics: 1.1 the signals observed in a narrow analysis band such as that normally used in communication receivers should be as close as possible to those of a noise having normal amplitude distribution and should be free from periodic components which, either directly or by heterodyning may be interpreted as a coherent signal, particularly by a listening watch; 1.2 depending on the local electrical characteristics of the ground and the location of the station in relation to the coastline, the ratio of the emission power to the normal atmospheric noise level should be chosen in such a way that: 1.2.1 at no point within the maritime area the noise level caused by emissions from the station and propagated by the ground wave at any time exceeds that of atmospheric noise; 1.2.2 at no point the noise level caused by emissions from the station and propagated by sky-wave reflection at any time exceeds a level of — 5 dB in relation to the atmospheric noise level; 2. that transmitters should be fitted with a device preventing the emission of a radiated power greater than a preset value; 3. that the introduction of new transmitting stations using spread-spectrum techniques in the MF band should be the subject of coordination between administrations of neighbouring countries to ensure compliance with the conditions laid down in § 1.2.1 and 1.2.2 above; 4. that when introducing new transmitting stations using spread-spectrum techniques in the MF band, coordination should be carried out in respect of receiving stations of other services, particularly those on or over land, to ensure that no harmful interference is likely to be caused to those receiving stations. * The Director of the CCIR is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO) and the International Association of Lighthouse Authorities (IALA). 268 Rec. 496-2 RECOMMENDATION 496-2 * LIMITS OF POWER FLUX-DENSITY OF RADIONAVIGATION TRANSMITTERS TO PROTECT SPACE STATION RECEIVERS IN THE FIXED-SATELLITE SERVICE IN THE 14 GHz BAND (1974-1982-1986) The CCIR, CONSIDERING (a) that Earth-to-space transmissions of the fixed-satellite service share the band 14-14.3 GHz with the radionavigation service; (b) that the World Administrative Radio Conference, Geneva 1979, has asked the CCIR to study the criteria for frequency sharing in this band (Recommendation No. 708, § 2.12); (c) that the Radio Regulations (No. 856) require that the use of this band by the radionavigation service shall be such as to provide sufficient protection to space stations in the fixed-satellite service; (d) that, in the band 14-14.3 GHz, sufficient protection for geostationary satellites in the fixed-satellite service can be obtained by limiting the power flux-density produced at the geostationary satellite orbit by stations of the radionavigation service; (e) that some kinds of radionavigation device, such as small ship radars and motor vehicle collision avoidance devices, although generally of comparatively low power, may be used in very large numbers; (f) Report 560, UNANIMOUSLY RECOMMENDS 1. that in order to provide sufficient protection to space station receivers of the fixed-satellite service, the following limits should apply: 1.1 that where the value of D, as defined below, is less than 2 x 10-4, the maximum value of the peak power flux-density produced at any point in the geostationary-satellite orbit by any radionavigation transmitter in the band 14-14.3 GHz should not exceed —150 dB(W/m2) in any 1 MHz band; 1.2 that where the value of D, as defined below, exceeds 2 x 10-4 the maximum value of peak power flux-density produced at the geostationary satellite orbit by any radionavigation transmitter should not exceed — 187 — 10 log D dB(W/m2) (1) in any 1 MHz band, where D is the estimated geographical density of radionavigation transmitters per km2 simultaneously active in any 1 MHz band, taking into account future needs and averaged over the territory of the administration concerned or over an area of 106 km2, whichever is less. * This Recommendation should be brought to the attention of Study Group 4. Rec. 546-2 269 SECTION 8E: DEFINITIONS (NO TEXTS) SECTION 8F: FREQUENCIES, ORBITS AND SYSTEMS RECOMMENDATION 546-2 * HYPOTHETICAL TELEPHONE REFERENCE CIRCUIT IN THE AERONAUTICAL, LAND AND MARITIME MOBILE-SATELLITE SERVICES (Question 82/8) (1978-1982-1990) The CCIR, CONSIDERING (a) that it is desirable to establish a hypothetical telephone reference circuit for systems in the mobile-satellite services, which would include associated feeder links, in order to afford guidance to designers of equipment and systems for use in telephone networks; (b) that, in systems in the mobile-satellite services, including associated feeder links, many technical character istics of the link in the land earth station to mobile earth station direction may differ substantially from those of the link in the mobile earth station to land earth station direction and hence two hypothetical telephone reference channels are required, UNANIMOUSLY RECOMMENDS 1. that the hypothetical telephone reference channel in the land earth station to mobile earth station direction consists of one land earth station to satellite to mobile earth station link (see Fig. 1); 2. that the hypothetical telephone reference channel in the mobile earth station to land earth station direction consists of one mobile earth station to satellite to land earth station link (see Fig. 2); 3. that the hypothetical telephone reference circuit be comprised of a link between a land earth station 4-wire audio-frequency band interface and a mobile earth station 4-wire audio-frequency band interface as defined in Fig. 3; 4. that echo control devices not be included within the hypothetical telephone reference circuit; 5. that should any voice processing equipment be used, for example, compandors, coders, decoders or voice-activated carrier switches, such equipment should be included within the hypothetical telephone reference circuit. * The Director, CCIR, is requested to bring this Recommendation to the attention of the CCITT. 270 Rec. 546-2 FIGURE 1 - Land earth station to mobile earth station hypothetical telephone reference channel FIGURE 2 - Mobile earth station to land earth station hypothetical telephone reference channel Satellite F IG U R E 3 - Functional block diagram of a mobile-satellite system defining the hypothetical telephone reference circuit PAGE INTENTIONALLY LEFT BLANK PAGE LAISSEE EN BLANC INTENTIONNELLEMENT Rec. 547 273 SECTION 8G: AVAILABILITY, PERFORMANCE OBJECTIVES AND INTERWORKING WITH TERRESTRIAL NETWORKS RECOMMENDATION 547 NOISE OBJECTIVES IN THE HYPOTHETICAL REFERENCE CIRCUIT FOR SYSTEMS IN THE MARITIME MOBILE-SATELLITE SERVICE (Study Programme 17A/8) (1978) The CCIR, CONSIDERING (a) that the hypothetical reference circuit is intended as a guide to the design and construction of actual systems; (b) that the costs of establishing and maintaining maritime mobile satellite systems are critically dependent on the overall signal-to-noise performance requirements; (c) that maritime mobile satellite systems will be connected to the international telephone network implying that CCITT Recommendation G.473 should be met; (d) that the total noise power in the hypothetical reference circuit (subjectively equivalent) should not unduly degrade conversation in most telephone calls; (e) that voice companding most probably will be used in order to reduce the constraint imposed by power limitation of the satellites; (f) that the extent of fading cannot be determined fully until more experimental data are available; (g) that the fading will depend on the elevation angle of the ship-borne antenna, the antenna directivity, the occurrence of calm sea conditions in various ocean areas, and the location of the ship-borne antenna relative to the reflecting surfaces of the ship; (h) that operator-to-operator calls should be possible even at small angles of elevation though with a degraded performance; (j) that there may be other sources of noise of short duration, UNANIMOUSLY RECOMMENDS 1. that the subjectively equivalent speech signal to psophometrically weighted noise ratio in the hypothetical reference Circuit as defined in Recommendation 546 should exceed the values shown in Fig. 1; 2. that these values of signal-to-noise ratio should be referred to non-faded conditions and to an angle of elevation of 10° of the ship-borne antennas; 3. that the modulation technique should give an acceptable decrease in quality with decreasing carrier-to- noise density ratio; 4. that the modulation technique and voice processing method adopted should permit quality comparable to that obtained in the fixed-satellite service when more satellite power is available. Note 1. — The noise objectives indicated in RECOMMENDS 1 above should include the effect of interchannel interference noise, co-channel interference noise, intermodulation noise as well as noise from atmospheric sources. Note 2. — The noise objectives stated in this Recommendation are applicable to systems using ship terminals with high-gain antennas (see Report 594). / Note 3. — The requirement for non-faded condition will probably be met for more than 80% of the tim^. When sufficient data on fading become available, this Recommendation should be supplemented to give noise objectives in terms of two percentages of time, e.g. 80% and 99%. 274 Rec. 547 Note 4. — The requirement in RECOMMENDS 1 corresponds to a noise level of 10 000 pWOp for speech levels below —35 dBmO and of 25 000 pWOp at a speech level of —20 dBmO. For speech levels above —20 dBmO, the speech signal to psophometrically weighted noise ratio should exceed 26 dB. Note 5. — The speech level is defined as the mean (time average) speech power while active. Note 6. — As soon as sufficient experimental and theoretical data for a particular system are available this Recommendation should be supplemented by a Recommendation stating the performance objectives in terms of measurable quantities such as idle channel noise power and test-tone-to-noise ratio. Note 7. — It is assumed that noise surges and clicks from power supply systems and from switching apparatus are reduced to negligible proportions and therefore will not be taken into account when calculating the noise power. Note 8. — This Recommendation does not take into account requirements to be met if facsimile and data transmission are required over telephone channels. Note 9. — In order to assure proper quality for high speech levels the minimum overload point of the channel should be defined. It should be taken into account that the average speech level and the range of variation of level as will be experienced at the inputs to the satellite system, may be different for shore originated and ship originated calls. It should be further noted that different modulation techniques may require different overload levels in order to yield an optimum performance. Note 10. — For an explanation of subjectively equivalent noise, and for methods by which it can be derived, see Report 751. Speech level (dBmO) F IG U R E 1 —'Limits of subjectively equivalent speech signal to psophometrically weighted noise ratio as a function of speech level Rec. 549-1 275 RECOMMENDATION 549-1 SIDE TONE REFERENCE EQUIVALENT OF HANDSET USED ON BOARD A SHIP IN THE MARITIME MOBILE-SATELLITE SERVICE AND IN AUTOMATED VHF/UHF MARITIME MOBILE RADIOTELEPHONE SYSTEMS (Study Programme 17A/8) (1978-1982) The CCIR, CONSIDERING (a) that the ambient acoustic noise to be expected on board ships is often significantly higher than on terrestrial telephone locations; (b) that room noise picked up by the side tone path of the handset should not introduce any further transmission impairment; (c) CCITT Recommendation G.121, Section E, UNANIMOUSLY RECOMMENDS that the side tone reference equivalent of the handset in the ships’ installation should be at least 17 dB. Note 1. — Noise levels in the range 50 to 80 dBA are to be expected on board ships, the actual level being dependent on locations on board ship, the ship’s size and structure. Note 2. — The need for a side tone may be discussed in view of the degradations it can create, Even when the value 17 dB is attained, room noise at expected levels may still have an adverse effect (CCITT Recommenda tion G: 121). .The recommended value is a compromise between the need for limiting impairment due to room noise and the possible need for a certain “liveliness” in the handset. Note 3. — The CCITT Recommendations on side tone could be subject to change as all aspects of side tone are under review. 276 Rec. 552 RECOMMENDATION 552 QUALITY OBJECTIVES FOR 50-BAUD START-STOP TELEGRAPH TRANSMISSION IN THE MARITIME MOBILE-SATELLITE SERVICE* (Study Programme 17A/8) (1978) The CCIR, CONSIDERING (a) that proper interworking of this telegraph transmission with the international telegraph services must be ensured; (b) CCITT Recommendation F.10 concerning character error rate for telegraph communications, UNANIMOUSLY RECOMMENDS that, for the shore station-to-mobile terminal and mobile terminal-to-shore station links, sufficient margin should be included to overcome adverse propagation conditions. The objective should be that propagation conditions should not contribute any character errors for at least 95% of all calls with mobile terminals within the satellite service area. With the exception of blockage effects, propagation conditions should not contribute more than 8 errors in 100 000 characters with a 99% confidence level for mobile terminals at the edge of the service area. * This Recommendation corresponds to CCITT Recommendation F.l 12. 277 SECTION 8H: EFFICIENT USE OF THE RADIO SPECTRUM CHARACTERISTICS AND SHARING OF FREQUENCY RESOURCES There are no Recommendations in this Section. PAGE INTENTIONALLY LEFT BLANK PAGE LAISSEE EN BLANC INTENTIONNELLEMENT SECTION 81: TECHNICAL AND OPERATING CHARACTERISTICS OF MOBILE SATELLITE SERVICES RECOMMENDATION 548 OVERALL TRANSMISSION CHARACTERISTICS OF TELEPHONE CIRCUITS IN THE MARITIME MOBILE-SATELLITE SERVICE (Study Programme 17A/8) (1978) The CCIR, CONSIDERING (a) that, when studying the interworking of a maritime satellite system with the automatic telephone network, a maritime satellite system can, from the technical point, be regarded as somewhat analogous with a national network and the ship terminals regarded as somewhat analogous to subscribers’ locations within that network, implying the network configuration of Fig. 1 (Note 1); (b) that, although several CCITT Recommendations of the G Series should apply to the maritime systems, these could involve requirements which would be )x>o stringent for the maintenance of performance of ship terminal equipment; (c) that relaxed requirements could be permitted where they will not cause a significant deterioration in the performance of the international network as experienced by subscribers in the existing terrestrial networks; (d) CCITT Recommendation G.473, UNANIMOUSLY RECOMMENDS that the design of the various items comprising a maritime system should permit the following transmission characteristics to be met: 1. the nominal frequency-band of a maritime satellite circuit should be either 300 to 3000 Hz or 300 to 3400 Hz. v • From a transmission performance point of view the latter is desirable but economic and/or technical considerations may favour the former; 2. the attenuation/frequency characteristics of any pair of ship terminal and shore station equipment should be within the limits shown in Fig. 2, referring to 800 Hz; 3. at 800 Hz the difference between the mean value (over time and over circuits) and the nominal value of the transmission loss of a maritime satellite circuit should not exceed 1 dB, and the standard deviation of the variation in transmission loss should not exceed 2 dB; 4. the linear crosstalk ratio (for potentially intelligible crosstalk only) between any two maritime satellite circuits should not be less than 58 dB, and between the go and return channels of any circuit not less than 55 dB; 5. if a maritime circuit is to be interconnected to a special quality leased international telephone circuit, then the group-delay distortion of the maritime circuit should not exceed the following limits: 500 Hz to 2800 Hz: 3 ms 600 Hz to 2600 Hz: 1.5 ms 1000 Hz to 2600 Hz: 0.5 ms Note 1. — Figure 1 illustrates three possible configurations for the shipboard installations and defines the nomenclature used for transmission study purposes in this Recommendation. This nomenclature is in accordance with the conventions of Recommendation 546. Note 2. — According to the conventions of CCITT Study Group IV, 800 Hz is the recommended frequency for single-frequency maintenance measurements on international circuits. However, by agreement between the administrations concerned, 1000 Hz may be used for such measurements. Multifrequency measurements made to determine the loss/frequency characteristic will include a measurement at 800 Hz, and therefore the reference for such characteristics can still be 800 Hz. 280 Rec. 548 Note 3. — Experience has shown that, in the case of equipments and apparatus complying with CCITT Recommendations, the level of non-linear distortion encountered in the general telephone network has no unacceptable effects on speqch transmission, or on the various non-speech signals conveyed by the network (e.g.: signalling, voice-band data, etc.). Note 4. — The attenuation/frequency characteristics given in § 2 of this Recommendation could be apportioned equally between the shore station equipment and the ship terminal equipment or, if advantageous, be apportioned unequally to the various elements comprising a maritime system. Maritime system III Virtual Shore station Ship station Shipboard switching four-wire audio four-wire audio switching points interface interface point Shore station Shipboard installation FIGURE 1 - Interconnection of circuits in the Maritime Mobile Satellite Service to the terrestrial network and corresponding nomenclature N otes: (1) From the point of view signalling and switching the shore station performs some of the functioning of an international transit centre (CT). , ( 2 ) a and b are the virtual switching points of the most-directly connected international circuit in the terrestrial network. (3) M and M' are the miscellaneous telephone equipment needed for the maritime satellite circuit, eg : signalling terminations, echo suppressors. (4) C and C are the channel units (i.e.: the channel transmitting and receiving equipments) which include voice-processing apparatus, eg: voice activated switches, companders, etc. (5) The attenuation-distortion of the two-wire/four-wire terminating unit is taken to be negligible over the band 300 to 3400 Hz. Attenuation (dB) 30 00 00 70 00 4000 3000 2700 2000 1000 300 0 1 - - S: | i i 1 1 1 1 1 1 1 1 1 1 1 I 1 sN I sS ■ I 2 - 2 E R U FIG ^ -^\ RECOM M ENDATIO N 550-1 USE OF ECHO SUPPRESSORS IN THE MARITIME MOBILE-SATELLITE SERVICE (Study Programme 17A/8) (1978-1986) The CCIR, CONSIDERING (a) that maritime mobile-satellite systems will be interconnected with the international telephone network; (b) that in order to achieve transmission objectives for the maritime mobile-satellite service which are in accordance with those of other international telephone connections, it is necessary to take into account the effects of echo; (c) CCITT Recommendation G.131 concerning the rules governing the use of half-echo suppressors; (d) CCITT Recommendation G.164 concerning the characteristics of half-echo suppressors; (e) CCITT Recommendation G.165 concerning the characteristics Of echo cancellers; (f) CCITT Recommendation Q.115 regarding control of echo suppressors, UNANIMOUSLY RECOMMENDS . 1. that half-echo suppressors or echo cancellers shall be fitted in the terrestrial part of the connection; 2. that if two-wire telephone sets are used at the ship terminal, a half-echo suppressor or an echo canceller shall be fitted at the ship end of the connection; 3. that if echo suppressors are fitted, they should have characteristics in accordance with CCITT Recommen dation G.164; 4. that if echo cancellers are fitted, they shall have characteristics in accordance with CCITT Recommenda tion G.165; 5. that it should be possible to disable echo suppressors, as described in CCITT Recommendation G.164, in both the terrestrial and the ship end of the connection; 6. that control of echo supressors in the terrestrial connection should follow the requirements estiablished in CCITT Recommendation Q.115; 7. that manual disabling of echo suppressors at the ship end of the connection should be possible; 8. that enabling of the echo suppressor, located at the ship end of the connection, must be done automatically when a call is terminated, independently of the disabling technique used. Note 1. See also CCITT Recommendations G.473 and M l 100 concerning the transmission plan for maritime satellite systems. Note 2. — For disabling of echo cancellers see CCITT Recommendation G.165, § 3.5 and 4. Note 3. — When tone disabling is used precautions must be made to ensure that the echo suppressor or echo canceller is not disabled by speech. Note 4. — CCITT Recommendation G.161 may still be used for the design of analogue echo suppressors. Rec. 553 283 RECOM M ENDATION 553 INTERFACE REQUIREMENTS FOR 50-BAUD START-STOP TELEGRAPH TRANSMISSION IN THE MARITIME MOBILE-SATELLITE SERVICE* (Study Programme 17A/8) (1978) The CCIR, CONSIDERING (a) that proper interworking of this telegraph transmission with the international telegraph services must be ensured; (b) that the shore station equipment will interface with the international terrestrial telegraph networks and will therefore need to conform to CCITT Recommendations where applicable; (c) that the ship station will include a local end with its termination consisting of start-stop equipment using International Telegraph Alphabet No. 2, UNANIMOUSLY RECOMMENDS 1. that the shore station equipment interfacing with terrestrial telegraph channels should conform to CCITT Recommendation R.101 (see Annex I) as applicable to 50-baud services: 1.1 for signals from the terrestrial network entering the shore station, the relevant points are: TABLE 1 Recommendation Item Parameter R.101 Point a Input modulation rate 2.1 ■ ' b Isolated character stop elements 2.2 ^ c Minimum interval between start elements 2.3 d No restrictions on the use of combinations of International Telegraph Alphabet No. 2 ■ 2.4 e Effective net margin . 2.5 f Minimum input start element duration 2.6 1.2 for signals from the shore station entering the terrestrial network, the relevant points are: TABLE II Recommendation Item Parameter R.101 Point g Output distortion 3.1 h Output m odulation rate 3.2 i Minimum output stop element 3.3 2. that the transmission characteristics of the ship terminal start-stop equipment should conform to CCITT Recommendation S.3 as applicable to 50-baud services. * The CCITT is at present considering the adoption of a similar Recommendation. 284 Rec. 553 ANNEX I The relevant sections of CCITT Recommendation R.101 * are reproduced below for information: “2. Start-stop channel inputs 2.1 The maximum speed tolerance that shall be accepted on continuous incoming 50-baud start-stop signals where a stop element of 1.4 units is employed shall be ± 2%. 2.2 The system shall accept isolated incoming 50-baud start-stop signals that have a 1-unit stop element. 2.3 The minimum interval between start elements of undistorted successive continuous characters that may be presented at the channel input when the nominal modulation rate is 50 bauds shall be 145 5/6 ms. 2.4 There shall be no restriction on the continuous transmission of all characters specified in 1. above (e.g. combination No. 32 of International Telegraph Alphabet No. 2) when they are presented at the maximum permitted rate. 2.5 The effective net margin on all channel inputs when undistorted signals are received from a transmitter having a nominal character length and rate shall be at least 40%. 2.6 To be recognized as valid, an input character start element shall be of at least 0.4 units’ duration at the nominal modulation rate of the input channel. 3. Start-stop channel outputs 3.1 The maximum degree of gross start-stop distortion shall be 3%. 3.2 The maximum difference possible between the mean modulation rate of the channel output signals and the nominal modulation rate shall be 0.2%. 3.3 When 50-baud characters are presented at any input rate within the specified range of this Recommenda tion, the minimum stop element duration released at the output shall be 1.25 units.” This Recommendation is at present under study and may be modified. Rec. 694 285 RECOMMENDATION 694 REFERENCE RADIATION PATTERN FOR SHIP EARTH STATION ANTENNAS (Question 88/8) (1990) The CCIR, CONSIDERING (a) that for coordination studies and the assessment of interference between ship earth stations and terrestrial stations, and between ship earth stations and the space stations of different satellite systems sharing the same frequency bands, it may be appropriate to use a single radiation pattern for each type of ship earth station antenna; (b) that the reference radiation pattern for ship earth station antennas must take account of the effect of local reflections from the sea, from ships’ superstructure, etc.; (c) that the use of antennas with the best achievable radiation pattern will lead to the most efficient use of the radio-frequency spectrum and the geostationary-satellite orbit; (d) Report 922, UNANIMOUSLY RECOMMENDS . 1. that a single reference radiation pattern for each type of ship earth station antenna should be used for: 1.1 coordination studies and the assessment of interference between ship earth stations in the mobile-satellite service and terrestrial stations in other services which share the same frequency bands; 1.2 coordination studies and the assessment of interference between ship earth stations in the mobile-satellite service and the space stations of different satellite systems which share the same frequency bands; 2. that the reference radiation pattern in Annex I should be used for ship earth station antennas having circular paraboloidal reflectors with diameters between 0.8 m and 1.3 m and with an operating frequency range of about 1500 to 1650 MHz; 3. that studies should continue in order to define the requirement for other types of ship earth station antennas. 286 Rec 694 ANNEX I REFERENCE RADIATION PATTERN FOR SHIP EARTH STATION ANTENNAS HAVING CIRCULAR PARABOLOIDAL REFLECTORS WITH DIAMETERS BETWEEN 0.8 m AND 1.3 m AND WITH AN OPERATING FREQUENCY RANGE OF ABOUT 1500 TO 1650 MHz G = Gmax - 2.5 x 10-3 (?•)' dB for 0 < G = 52 — 10 log — — 25 log (p dB for 100 — < cp < cpi X D G = 0 dB for (pj < D Qm — 20 ^ Gmax 2^ 15 log (degrees) (pt = 120 ( i r (degrees) G: gain of the antenna relative to isotropic (dB) Gmax: maximum gain of the antenna relative to isotropic (dB) D : antenna diameter expressed in the same unit X: wavelength Note — The reference radiation pattern should be assumed to be rotationally symmetrical. Rec. 632-1 287 SECTION 8J: TECHNICAL AND OPERATING CHARACTERISTICS OF RADIOCOMMUNICATIONS USING SATELLITE DISTRESS AND SAFETY OPERATION AND OF RADIO DETERMINATION SATELLITE SERVICES RECOMMENDATION 632-1 * TRANSMISSION CHARACTERISTICS OF A SATELLITE EMERGENCY POSITION-INDICATING RADIOBEACON (SATELLITE EPIRB) SYSTEM OPERATING THROUGH GEOSTATIONARY SATELLITES IN THE 1.6 G H z BAND (Question 90/8) * (1986-1990) The CCIR,' . , CONSIDERING (a) that satellite EPIRBs are one of the prime alerting means in the Global Maritime Distress and Safety System (GMDSS) adopted by the International Maritime Organization (IMO); (b) that the satellite EPIRB system operating through geostationary satellites in the 1.6 GHz band is one of two satellite-based distress alerting systems developed for use in the GMDSS; (c) that all ships to which Chapter IV of the International Convention for the Safety of Life at Sea (SOLAS) 1974, as amended in 1988, applies will be required by Regulation IV/7.1.6 to carry a satellite EPIRB from 1 August 1993; - ' (d) that SOLAS Regulation IV/7.1.6 permits the carriage of a satellite EPIRB operating through the INMARSAT geostationary-satellite system, subject to the availability of appropriate receiving and processing ground facilities for each ocean region covered by INMARSAT; (e) that pre-operational demonstrations have been satisfactorily completed; (f) that the IMO has adopted Resolution A.661(16) — Performance standards for float-free satellite EPIRBs operating through the geostationary INMARSAT satellite system on 1.6 GHz; (g) that ships to which the 1974 SOLAS Convention does not apply will use elements of the GMDSS, including satellite EPIRBs, some of which may not meet all of the requirements established by the IMO in Resolution A.661(16); (h) the necessity to make available satellite EPIRB production units, and to gain operational experience within the remaining time-frame; (j) that the frequency band for satellite EPIRBs available through the First generation INMARSAT space segment is 1644.3-1644.5 MHz; (k) that the second generation INMARSAT space segment, which is planned to commence operation from 1990 onwards, will cover both the band 1644.3-1644.5 MHz and the band 1645.5-1646.5 MHz; I) that the number of potential users, including non-convention ships, cannot yet be estimated; m) that the amount of spectrum for the 1.6 GHz satellite EPIRB system necessary to meet the presently foreseen operational capacity requirements is less than 200 kHz, UNANIMOUSLY RECOMMENDS 1. that the transmission characteristics of all types of satellite EPIRBs operating through geostationary satellites at 1.6 GHz should be in accordance with Annex I to this Recommendation; 2. that the transmission frequencies of satellite EPIRBs be distributed uniformly across the frequency band appropriate to the space segment in use; * The Director, CCIR, is requested to bring this Recommendation to the attention of the International Maritime Organization (IMO), the International Civil Aviation Organization (ICAO), and the International Maritime Satellite Organization (INMARSAT). 288 Rec. 632-1 3. that the operational implementation of the 1.6 GHz satellite EPIRB system as it applies to the second and subsequent generations of the INMARSAT space segment be initiated in the spectrum between 1645.6 and 1645.8 MHz; 4. that until all satellites of the inmarsat first generation space segment (spare and operational) are completely replaced, all types of satellite EPIRBs will transmit sequentially on both 1644.3-1644.5 MHz and 1645.6-1645.8 MHz. ANNEX. I TRANSMISSION CHARACTERISTICS OF A SATELLITE EMERGENCY POSITION-INDICATING RADIOBEACON (SATELLITE EPIRB) SYSTEM OPERATING THROUGH GEOSTATIONARY SATELLITES IN THE 1.6 GHz BAND Modulation: non-coherent binary frequency shift keying (FSK) Transmit frequency:* within the bands 1644.3-1644.5 MHz**and 1645.5-1646.5 MHz*** Deviation: — 120 Hz (0) + 120 Hz (1) tolerance ±1% Accuracy of clock frequency: ± 2 x 10_6/year **** Transmit frequency: — long term accuracy (for 1 year): better than ± 3 x 10-6 ■ — short term stability: 1 x 10-8 for 1 min FSK switching time: 80% transmit power within 1.5 ms Transmit power: 0 dBW ± 1/3 dB at the input to the antenna Antenna: 0 dBi nominal gain (shaped beam or hemispherical) Antenna axial ratio: < 5 dB for ± 90° from zenith Polarization: right-hand circular Frame length: — data: 100 bits (see Appendix I) — synchronization: 20 bits (see Appendix I) — parity bits: 40 bits (see Appendix II) Code: NRZ-L Modulation rate: 32 baud Total transmission duration: 40 min Number of transmissions: 4 (see Appendix III) * Until all satellites of the INMARSAT first generation space segment (spare and operational) are completely replaced, all types of satellite EPIRBs will transmit sequentially on both frequency bands of the INMARSAT first and subsequent generation space segments. ** INMARSAT first generation space segment. *** INMARSAT second generation space segment. **** This requires a clock accuracy of ± 2 x 10_7/year in the receiver processor. Rec. 632-1 289 APPENDIX I OF ANNEX I 1. The following items, listed in the preferred priority order for entry and read-out, should be included in distress messages to the extent practicable and necessary: T A B L E I — Content of distress message N um ber Item C ontents o f bits 1 Ship station identity 30 2 ' Position co-ordinates and information in the following order: 2 . 1 Latitude in degrees and minutes 14 2 . 2 • Longitude in degrees and minutes 15 . 2.3 ' Date and time of position up-date 1 1 3 Nature of distress 4 4 Course 9 5 Speed 6 6 Date et time of activation 1 1 7 Assistance desired and any other information which might facilitate the rescue (’) , (') Item 7 may be included with the data sent in item 3, if necessary. N ote — The order of items does not necessarily mean that the message sequence during transmission follows exactly in this order but the input/output data could be used in the order as proposed by IMO and as given above. ’ 290 Rec. 632-1 2. The format of the transmitted message and string is shown in Table II and Fig. 1 of Appendix II. TABLE II — Format of the transmitted message (See Note, Table I) Synchronization bits 2 0 bits H ex E D E 20 Distress message 30 bits Ship station identity range: 0-999.999.999 1 bit Longitude hemispherical symbole 0 : east; 1 : w est 1 bit Latitude hemispherical symbole 0 : north; 1 : south 8 bits Degrees of longitude range: 0-180 6 bits Minutes of longitude range: 0-60 7 bits Degrees of latitude range: 0-90 6 bits Minutes of latitude range: 0-60 9 bits Course: degrees (true) range: 0-360 5 bits Time of position up-date: h (UTC) range: 0-24 6 bits Time of position up-date: min range: 0-60 5 bits Time of activation: h (UTC) range: 0-24 6 bits Time of activation: min range: 0-60 6 bits Speed: knots range: 0-63 1 4 bits Nature of distress (see Table III) Parity bits 40 bits See Appendix II for composition Rec. 632-1 291 In those systems where it is desirable: to provide on activation, a specific indication of the nature of distress, the following indications should be used: TABLE III — Nature of distress indications IMO Binary code Nature of distress indicator 1 0 0 0 1 Fire/explosion 2 0 0 1 0 F loodin g 3 0 0 1 1 C ollision 4 0 1 0 0 G roundind 5 0 1 0 1 Listing, in danger of capsizing 6 0 1 1 0 Sinking 7 0 1 1 1 Disabled and adrift 8 0 0 0 0 Undesignated (unspecified distress) 9 1 0 0 0 Abandoning ship 1 0 1 1 1 1 Test (') (’) Use of this indicator should be restricted to those applications where trans mission of the distress alert (or call) is required to ascertain that the system is 1 . operating properly. Provisions may be required to, confirm that the complete system is functioning. Additional capacity should be provided if practical. APPENDIX II OF ANNEX I FORWARD ERROR-CORRECTION CODE 40 parity bits for error correcting purpose. A (140, 100, 5) BCH code is used resulting in a minimum code distance of 11. ^ The input message , C2, ... ,-Cj Cti . c , D is t r e s s = 0 m e s s a g e M S B 51 is divided modulo 2 by the following generator polynomial: 36 g(x) = x40 + X3 7 . + x 3 0 4- + X3 ,2 9 27 ,2 6 ,2 4 22 + X3 0 + xz* + xzo + xz/ + XZD + + X23 + Xzz + .15 -I- X2 0 + . + X16 + X13 + X 1 + + x 10 + .+ X4 + + 1 The remainder of this division represents the parity bits C'ioi , • • •, Ci40. The output message is generated by inserting the parity bits in the output message. Resultant output message: Ci,C2, ... ,C100, Cl01, ... , Cj D is t r e s s Parity bits m e s s a g e . M S B LSB* * MSB: most significant bit. ** LSB: least significant bit. | | , u s 1 MSB 1 j / 1 0 0 1 1 1 Degrees (8 1 119° bits) 1 0 0 Synchronization 1 1 1 0 2 ( 1 longitude 1 bits) 1 f o 1 0 0 0 1 (6 0 Min bits) 19' 0 0 1 1 0 1 0 0 0 0 1 IUE - - 1 FIGURE 0 Degrees 7 bits) (7 S: s sgiiat bit significant ost m MSB: E: owr ro-orcin code error-correction forward FEC: LSB: least significant bit significant least LSB: - The HSD. o f the data frame is transmitted first transmitted is frame data the f o HSD. The repeated - periodically is frame data The - 0 39° 0 uig h woe prtn time operating whole the during 0 1 1 1 latitude 0 rnmitdmsaesrn (xmple) (exam string message itted Transm 1 Se t,Tbe I) Table ote, N (See 0 0 f 0 1 0 (6 . 0 Min bits) 1 00 1 0 ' 0 0 1 0 1 1 1 0 0 hpsain identity Ship-station 0 0 Course 9 bits) (9 314159265” 5 6 2 9 5 1 4 1 “3 0 260° 1 3 bits) (30 0 1 0 0 1 1 0 1 0 0 0 Hemispherical sym bol bol sym Hemispherical 0 ie oiin up-date position f o Time Hemispherical sym bol east bol sym Hemispherical 5 bits) (5 0 1 Hours 0 10 h 0 0 1 1 0 0 0 1 1 0 1 1 (6 0 4 min 44 Min bits) t j rth o n 0 0 south west /w 0 / 1 0 1 / 9 Rc 632-1 Rec. 292 Rec. 632-1 293 APPENDIX III OF ANNEX I D U T Y C Y C L E 1. The duration of each transmission period should be 10 min. Until all satellites of the INMARSAT first generation space segment (spare and operational) are completely replaced, all types of satellite EPIRBs will transmit sequentially for 5 min on each of the frequency bands 1644.3-1644.5 MHz and 1645.5-1646.5 MHz.. 2. The first transmission should be initiated when the distress occurs either by manual activation from on board the ship or when the satellite EPIRB floats free. 3. The second transmission should begin 45 min after the start of the first, to overcome possible interruptions caused by shadowing due to the superstructure of the abandoned ship. 4. To further increase the probability of a successful transfer of the distress alert, two additional trans missions should follow the first two, the third 130 min, and the fourth 240 min, after the start of the first transmission. 5. The transmission repetition rate is illustrated as follows: , — — — ^ t (min) 0 10 45 55 130 140 240 250 294 Rec. 633-1 RECOMMENDATION 633-1 * TRANSMISSION CHARACTERISTICS OF A SATELLITE EMERGENCY POSITION-INDICATING RADIOBEACON (SATELLITE EPIRB) SYSTEM OPERATING THROUGH A LOW POLAR-ORBITING SATELLITE SYSTEM IN THE 406 MHz BAND (Question 90/8) (1986-1990) The CCIR, CONSIDERING (a) that satellite EPIRBs can be used for distress alerting in the maritime, land and aeronautical environ ments; (b) that satellite EPIRBs with common characteristics may be employed in diverse operating environments; (c) that satellite EPIRBs are one of the prime alerting means in the Global Maritime Distress and Safety System (GMDSS) of the International Maritime Organization (IMO); (d) that all ships to which Chapter IV of the International Convention for the Safety of Life at Sea (SOLAS) 1974, as amended in 1988, applies will be required by Regulation IV/7.1.6 to carry a satellite EPIRB from 1 August 1993; (e) that SOLAS Regulation IV/7.1.6 provides for the carriage of a satellite EPIRB operating in the 406 MHz band; (f) the necessity to gain operational experience with globally received data by 1 August 1993; (g) the assured availability of four operational COSPAS-SARSAT type satellites in orbit until the year 2003 and the planned availability thereafter; (h) the current and projected availability of the COSPAS-SARSAT ground system; (j) the test results presented in Report 919, UNANIMOUSLY RECOMMENDS 1. that the transmission characteristics for a satellite EPIRB operating through a low polar-orbiting satellite system in the 406 MHz band should be in accordance with Annexes I and II to this Recommendation; 2. that administrations be discouraged from using data formats not covered by this Recommendation. * The Director, CCIR, is requested to bring this. Recommendation to the attention of the International Maritime Organization (IMO), the International Civil Organization (ICAO), the International Maritime Satellite Organization (INMARSAT), and the COSPAS-SARSAT Secretariat, Rec. 633-1 295 ANNEX I T A B L E I — 406 MHz satellite EPIRB characteristics Parameter . V alue R F signal: Carrier frequency ('): initial 406.025 MHz ± 0.002 MHz Frequency stability ('): short term < 0 . 0 0 2 parts/million in 1 0 0 m s medium term: mean slope (2) < 0 . 0 0 1 parts/million/min residual frequency variation (2) < 0.003 parts/million lon g term ± 0.005 MHz within 5 years including the initial offset For the interim period until 1 January 1991, the following relaxation in frequency stability is permitted: medium term: mean slope (2) < 0 . 0 0 2 parts/million/min residual frequency variation (2) < 0.005 parts/million Power output 5 W ± 2 dB measured into 50 Q, load with VSWR < 1.25 : 1 Power output rise time < 5 ms, measured between 10% and 90% power points In-band spurious emissions See Fig. 1 Data encoding Biphase L (see Fig. 2) M odulation Phase modulation positive and negative 1.1 ± 0.1 radians peak referenced to an unmodulated carrier (see Fig. 2) Modulation rise (t *) and fall (xf) times 150 ps ± 100 ps (Fig. 3) Modulation symmetry |ti — ^ / ( ti + t2) < 0.05 (see Fig. 4) - Continuous emission failure mode Continuous transmission should not exceed 45 s Warm-up time All technical characteristics should be met within 15 min from turn on when transmitting within operating temperature range Digital message: (See Fig. 5) Repetition period (3) 50 s ± 5% Transmission time (4) 440 ms ± 1% (or 520 ms ± 1% for optional long message) CW preamble (5) X 160 m s ± 1 % Digital message 280 ms ± 1% (or 360 ms ± 1% for optional long message) Bit rate 400 bit/s ±1% Bit synchronization A ll “ Is” (15 “ 1” bits) Frame synchronization 0 0 0 1 0 1 1 1 1 in normal operation, or 0 1 1 0 1 0 0 0 0 during on-air self test A ntenna (6): E levation 5° to 60° Pattern Hemispherical Polarization Circular (RHCP) or linear Gain (vertical plane) Between — 3 dBi and + 4 dBi over 90% of the above region Gain variation (azimuth plane) < 3 dB V SW R (7) < 1.5 : 1 Operating temperature range Minimum acceptable (8) -20 °C to +55 °C Optional (9) < -20 °C to > +55 °C Long-term temperature gradient 5 ° C /h Thermal shock 30 °C temperature difference with a degraded performance for 15 m in Minimum operating life time (,0) 24 h at any temperature throughout the specified operating temperature range 296 Rec. 633-1 Footnotes relative to Table I: (') Specified values apply after 15 min warm-up and for VSWR < 3 1. (2) The mean slope and residual frequency variation shall be measured as follows; Data shall be obtained by making 18 sequential frequency measurements, one every repetition period (50 s ± 5%) over an approximate 15 min interval. Each • measurement shall be a 100 ms frequency average performed during the modulated part of the message. The mean slope is defined as that of the least-squares straight-line fit to the 18 data points. Residual frequency variation is defined as the r.m.s (root mean square) error of the points relative to the least-squares estimate. (3) The repetition period shall not be so stable that any two transmitters appear to be synchronized closer than a few seconds over a 5-min period. The intent is to randomize the period between transmission bursts such that no two satellite EPIRBs will have all of their bursts coincident. An acceptable alternative for a production run of any type or model of satellite EPIRB would be an equal distribution of fixed repetition periods of 8 or more values approximately equally spaced over the range of 47.5 s to 52.5 s. (4) Measured at the 90% power points. (5) Measured between the 90% power point and the beginning of the modulation. ' (6) Antenna characteristics should be verified in a configuration as close as possible to its operational condition. (7) The satellite EPIRB shall not be damaged by any load from open circuit to short circuit. (8) This temperature range is also the IMO recommended performance standard (IMO Resolution A.611(15)). \ (9) This extended specification may be applied at the discretion of each administration. (10)For installations meeting IMO recommended performance standards (IMO Resolution A,611(15)), a minimum operating life time of 48 h at any temperature throughout the specified operating temperature range is necessary. ■ P r 0 dB, - 5 - 1 0 m -1 5 -20 dB, - 2 0 d B , - 2 0 - 2 5 - 3 0 dB, - 3 0 dB, -3 0 -35 dB, - 3 5 dB, —35 -40 dB, - 4 0 dB, - 4 0 - 4 5 - , 5 0 L - y / -/H - 2 4 -12 -7 -3 +3 +7 . +12 + 24 fc 406.0 MHz Relative frequency of satellite EPIRB (kHz) 406.1 MHz FIGURE 1 — Spurious emission mask for 406.0 MHz to 406.1 MHz band Pc : Satellite EPIRB unmodulated carrier power output f c : Satellite EPIRB carrier frequency . ■ t dB : Satellite EPIRB emitted signal power level in dB relative to Pc c (measured in a 100 Hz resolution bandwidth) Rec. 633-1 297 i i i i i ii i t | Bit period Non-return-to- zero (NRZ) data Pi = + 1 . 1 rad — — 0 rad Modulation sense FIGURE 2 - Data encoding and modulation sense FIGURE 3 - Definition of modulation rise and fall times (Figure not to scale) 298 Rec. 633-K Optional extra bits for long message • 160 ms carrier .15 bits 9 bits 87 bits 32 bits | | 1 bit | (1) ( 2 ) (3) FIGURE 5 - Transmitted message format (1) Bit synchronization: 15 ”1” bits (2) Frame synchronization: 000101111 in normal operation, or 0 1 1 0 1 0 0 0 0 during on-air self test ( 3 ) ” 0 ” bit indicates short-message format ” 1 ” bit indicates long-message format Rec. 633-1 299 ANNEX II SATELLITE EPIRB CODING 1. General This Annex defines the 406 MHz satellite EPIRB digital message coding (see Fig. 6). The digital message is divided into six major fields. For each field, the most significant bit (MSB) is transmitted first. o 3 G *1* (D ccj G Bit e-S Error- 53.2 synchro 2 c correction S "K Optional extra bits nization rT. Protected field (61 bits) code ' w c for long message 112 1 15 16 24 25 85 86 106 107 113 144 160 ms 15 bits 9bits la la 10bits 49 bits 21 bits 32 bits carrier bits 6 (1)(2) (3) (4) FIGURE 6 - Message format (1) Message-format flag: ”0” indicates short message ” 1 ” indicates long message (2) Protocol flag (3) MID (Maritime Identification Digit) code (see § 2.2) (4) Data field Satellite EPIRBs may be coded either for a short message or for an optional long message format as described below: — the short message format includes a unique identification number which accommodates either the ship station identity or an identity which meets the special needs of aeronautical or other users. The short message can provide additional information such as type of auxiliary radio-locating device, user type, and location of the satellite EPIRB or other information as desired; — the optional long-message format provides all information necessary to meet the GMDSS requirements, e.g. maritime users can report course, speed, nature of distress and time of satellite EPIRB activation in accordance with the IMO proposals for content of the distress message; — the assignment of ship station identities and maritime identification digits (MID) shall be in accordance with the relevant ITU maritime mobile service identities (see Appendix 43 to the Radio Regulations) or relevant national standards; — administrations should note that any applications of data formats indicated as “spare” or other options not defined in this Annex will not be decoded by operators of the COSPAS/SARSAT system. However, COSPAS/SARSAT Secretariat is willing to consider proposals from administrations for other data formats. 300 Rec. 633-1 The six major message bit fields are described in Table II and the details of the last four message bit fields are summarized in Table III. TABLE II — Major message-bit fields Bit-field name Bit-field location 1. Bit synchronization Bit 1 to bit 15 2. Frame synchronization Bit 16 to bit 24 3. Protected field Bit 25 to bit 85 4. Error-correction code Bit 8 6 to bit 106 5. Emergency-code/national-use field Bit 107 to bit 112 6 . Long message (optional) Bit 313 to bit 144 A bit-synchronization pattern consisting of a series of “Is” shall occupy the first 15 bit positions. A frame-synchronization pattern consisting of 9 bits shall occupy bit positions 16 to 24. The frame- synchronization pattern in normal operation shall be “000101111”. However, if the satellite EPIRB radiates a modulated signal in the self-test mode, the frame-synchronization pattern shall be “011010000” (i.e. the last 8 bits are complemented) and any RF transmission (modulated or unmodulated) must be limited to one burst of 440 ms maximum. The error-correction code is used with both the short-message format and the long-message format and is based on a (127, 106) triple error-correcting BCH code with the following generator polynomial: gs (x) = g3 (x) • (7,4,3,2,0) & (x) = gx (x) • (7,3,2,1,0) gx (x) = (7,3,0) T A B L E III Summary of coding options for 406 MHz beacons b 25: message-format flag (0 = short message, 1 = long message) b 26: protocol flag ( 0 = maritime/location protocol, 1 = user protocols) ' b 27 — b 36: maritime identification digits (MID), Appendix 43 of the ITU Radio Regulations Maritime/location protocol (b 26 = 0) User protocol (b 26 = 1) l 0 0 0 = orbitography 1 1 0 — radio call sign b 37 — b 56: trailing 6 digits of ship station identity (binary b 37 — b 39: User protocol type <001 = aviation 111 = test coded) i 0 1 0 = maritime 1 0 0 = spare \ 0 1 1 = serialized 1 0 1 = spare b 57 — b 85: location (binary coded) Maritime user Radio call sign user Serialized user Aviation user b 57 — b 63: latitude (degrees) (b 37 — b 39 = 010) (b 37 - b 39 = 110) (b 37 - b 39 = 011) (b 37 - b 39 = 001) b 64 — b 69: latitude (min) b 40 - b 75: trailing 6 digits of ship b 40 — b 63: first four characters b 40 - b 43: be aeon type b 40 - b 81: b 70: 0 = North, 1 = South station identity or radio (modified Baudot) registration b 71 — b 78: longitude (degrees) 0 1 0 0 : maritime 0 0 0 0 : aviation call sign (modified b 64 — b 75: last three characters marking 1 0 0 0 : survival 1 1 0 0 : personal b 79 — b 84: longitude (min) Baudot) (binary coded decimal) (m odified b 44 — b 63: serial number Baudot) b 85: 0 = East, 1 = West b 76 — b 81: specific beacon b 76 — b 81: specific beacon b 64 — b 83: national use, not . (modified Baudot) (modified Baudot) defined b 82 — b 83: 0 0 = spare b 82 — b 83: 00 = spare b 82 — b 83: 00 = spare I 0 0 = no auxiliary radio-locating device e. 3- 301 633-1 Rec. b 84 — b 85: Auxiliary radio-locating device type(s) ( 1 1 = other auxiliary radio-locating device(s) b 8 6 — b 106: error-correction code for b 25 — b 85 , , n, , e . u i n { 0 = national use, undefined b 107: emergency-code use of b 109 — b 112 . « 1 = emergency-code flag b 108: 0 = manual activation only type of beacon 1 = automatic and manual activation type of beacon b 109 — b 112: nature of distress as indicated by IMO (Table XVI) b 109 — b 112: non-maritime user emergency code b 109: 1 = fire, 0 = no Tire b 1 1 0 : 1 = medical help needed, 0 = no medical help needed b 1 1 1 : 1 = disabled, 0 = not disabled b 1 1 2 : 0 = spare b 113 — b 144: optional long m essage b 113 — b 144: optional long message for user protocols for maritime/location b 113 — b 114: 00 = latitude/longitude flag; 01, 10, 11 = spare protocol b 115 — b 121: latitude (degrees) b 113 — b 121: course b 122 — b 127: latitude (minutes) A b 1 2 2 — b 126: speed b 128: 0 = North, 1 = South r 7* CZ o b 127 — b 139: activation time b 129 — b 136: longitude (degrees) z nv r - 1 b 127 — b 129: day of week b 137 — b 142: longitude-(minutes) b 130 - b 134: hour b 143 : 0 = East, 1 = West 'V V b 135 — b 139: m inute (2-m in b 144:. even parity applied to b 113 — b 143 increments) b 140 — b 144: optional national use 302 Rec. 633-1 2. Protected field The protected field consists of 61 bits (i.e. bit 25 to bit 85 inclusive) which are “protected” by application of the error-correction algorithm. The first bit (i.e. bit 25) is a format flag which shows whether the message is short or long using the following coding: 0: short format 1: long format The identification (ID) field, which begins at bit 26 after the format flag and ends at bit 85, has the general structure as shown in Table IV. T A B L E IV — Identification field bit structure Bits U sage 26 Protocol flag . 27-36 MID code (see § 2.2) 37-85 D ata field 2.1 Protocol flag Bit 26 in the ID field is used to identify the type of protocol being used by a satellite EPIRB, i.e. maritime/location protocol (bit 26 = 0) or for one of 8 possible user protocols (bit 26 = 1). 2.2 Maritime Identification Digits Bits 27 to 36 in the ID field designate 3-digit decimal country code number expressed in binary notation. These codes are based on the Maritime Identification Digits (MID), assigned by the ITU from Appendix 43 to the Radio Regulations. 2.3 Maritime/location protocol 2.3.1 Short message The short-message structure of the maritime/location protocol is shown in Table V. TA B L E V — Maritime/location protocol short-message structure Bits U sage 26 Protocol flag (=0) 27-36 - MID code (see § 2.2) 37-56 20 bits ID (trailing 6 digits of ship station identity) 57-85 29 bit location Use of this protocol requires recalculation of the BCH error-correcting code after each vessel position update. The MID for the maritime/location protocol is that of the country of vessel registration, and it is coded in bits 27 to 36. Bits 37 to 56 designate 6-digit decimal number of the ship station identity expressed in binary notation. The formation of this identity is described in Appendix 43 to the Radio Regulations. Bits 57 to 85 designate the location in binary notation, as shown in Table VI. Rec. 633-1 303 TABLE VI — Maritime/location protocol location field bit structure Bits U sage 57-63 Latitude (degrees) 64-69 Latitude (min) 70 0: N orth; 1: South 71-78 Longitude (degrees) 79-84 Longitude (min) 85 0: East; 1: W est However, when no location has been entered, bits 57 to 63 and bits 71 to 78 should be set to “Is”, and bits 64 to 70 and bits 79 to 85 should be set to “Os”. 2.3.2 Long message (optional) The long message is not in the “protected” field. At present, only one option exists for this protocol as shown in Table VII. These bits (113 to 144) follow the error-correction and emergency codes (see Fig. 6). . TABLE VII — Maritime/location protocol long-message structure Bits Item U sage 113-121 C ourse Degrees true; range from 0 to 359 122-126 Speed Knots; range from 0 to 31 127-129 Time of activation Day of week (000 = Sunday); range from 0 to 6 130-134 Hours; from 0 to 23 135-139 Minutes (2-min increments); range from 0 to 58 140-144 O ptional National use (') (') National option: it is desirable for administrations having alternative uses to so advise the COSPAS/SARSAT Secretariat and the appropriate SAR authorities (see § 1). The message-format flag, bit 25, should be set to (= 0) for a short-message transmission, but it should be switched automatically to (= 1) when data is entered in bits 113 to 144 for the long-message transmission. This will require two separate BCH codes: one for use with message-format flag (= 0) (short-message format) and one for use with message-format flag (= 1 ) (long-message format). User protocols The user protocol short-message structure is shown in Table VIII. TABLE VIII — User protocol short-message structure Bits U sage 26 Protocol flag (=1) 27-36 MID code (see § 2.2) . 37-39 User protocol type 40-83 D ata field 84-85 Auxiliary radio-locating device type(s) 304 Rec. 633-1 Bits 37 to 39 in the user protocol-type field designate one of 8 user protocols and are expressed as one octal character. This determines how the remaining bits in the data field are encoded/decoded. The 8 user protocols are shown in Table IX. TABLE IX — User protocol types Binary Octal User protocol type num ber character 0 0 0 0 Orbitography 0 0 1 1 A viation 0 1 0 2 M aritim e 0 1 1 3 •Serialized 1 0 0 4 Spare 1 0 1 5 Spare 1 1 0 6 Radio call sign 1 1 1 7 Test Bits 40 to 83 are used to encode the actual identification of the satellite EPIRB and are defined separately for each user protocol. Bits 84 to 85 are used to indicate the type of auxiliary radio-locating device(s) of Cach user protocol (excluding orbitography satellite EPIRBs). The assignment of bits is as follows: 00: no auxiliary radio-locating device 01: 121.5 MHz 10: maritime locating: 9 GHz search and rescue radar transponder (SART) 11: other auxiliary radio-locating device(s) (see Note) Note — It is desirable that administrations using the “other auxiliary radio-locating device(s)” category (i.e. bits 84 to 85 = 11) advise COSPAS-SARSAT Secretariat and the appropriate SAR authorities as to which auxiliary radio-locating device(s) and its (their) signal characteristics they are using. Of other auxiliary radio-locating device(s) is (are) used in addition to 121.5 MHz, the code for 121.5 MHz (i.e bits 84 to 85 = 01) should be used. 2.4.1 Orbitorgraphy user protocol (user protocol 000) The orbitography user protocol is for use by special system calibration transmitters and is intended for use only by operators of the local user terminals. \ 2.4.2 Aviation user protocol (user protocol 001) The short-message structure of the aviation user protocol is shown in Table X. T A B L E X — Aviation user protocol short-message structure Bits U sage 26 Protocol flag (=1) 27-36 MID code (see § 2.2) 37-39 User protocol type (= 001) 40-81 Aircraft registration marking (see Note) 82-83' Spare (=00) 84-85 Auxiliary radio-locating device type(s) Rec. 633-1 305 Bits 27 to 36 designate the country in which the aircraft is registered. However, it may also indicate the country to which an aircraft has been leased if the national authority in the leasing country requires ' this information within the country code. Bits 40 to 81 designate the aircraft registration marking (see Note) which is encoded using the modified-Baudot code shown in Table XI. This code enables 7 characters (6x7 = 42) to be encoded using 42 bits. This data will be right justified with a modified-Baudot space (100100) being used where no character exists. Note — This protocol may not be applicable for all commercial aircraft. Further study of protocols for commercial aircraft is necessary. TABLE XI — Modified-Baudot code C ode C od e Letter (’) Figure (') M SB LSB M SB LSB A 111000 ( - H 2) 011000 B 110011 C 101110 D 110010 E 110000 3 010000 F 110110 G 101011 H 100101 I 101100 8 001100 J >111010 K 111110 L 101001 M 100111 N 100110 O 100011 9 000011 P 101101 0 001101 Q 111101 1 011101 R , 101010 4 001010 S 110100 T 100001 5 000001 U 111100 7 011100 V 101111 w 111001 2 011001 X 110111 /. 010111 Y 110101 6 010101 z 110001 ()(3) 100100 MSB: most significant bit. LSB: least significant bit. (') Letters/figures shift is shown by the most significant bit, i.e.: 1 = letters 0 = figures (2) H yphen . (3) Space 306 Rec. 633-1 2.4.3 Maritime user protocol (user protocol 010) The short-message structure of the maritime user protocol is shown in Table XII. TABLE XII — Maritime user protocol short-message structure Bits U sage 26 Protocol flag (=1) 27-36 MID code (see § 2.2) 37-39 User protocol type (= 010) 40-75 Radio call sign or trailing 6 digits of ship station identity 76-81 Specific satellite EPIRB 82-83 Spare (=00) 84-85 Auxiliary radio-locating device type(s) Bits 27 to 36 designate the country of vessel registration. Bits 40 to 75 designate the radio call sign or the trailing 6 digits of the 9-digit ship station identity using the modified-Baudot code shown in Table XI. This code enables 6 characters (6x6 = 36) to be encoded using 36 bits. This data will be right justified with a modified-Baudot space (100100) being used where no character exists. If all characters are digits' the entry is interpreted as the trailing 6 digits of the ship station identity. Bits 76 to 81 are used to identify specific satellite EPIRBs on the same vessel (the first or only float-free satellite EPIRB should be coded with a modified-Baudot zero (001101); additional satellite EPIRBs should be numbered consecutively using modified-Baudot characters 1 to 9 and A to Z). The maritime user and the radio call-sign user protocols may be used for satellite EPIRBs that require coding with a radio call sign. The maritime user protocol should be used for radio call signs of 6 or fewer characters. 2.4.4 Serialized user protocol (user protocol 011) The serialized user protocol is intended to permit the manufacture of satellite EPIRBs whose ID will be identified by a data base giving specifics about the unit. The short-message structure of the serialized user protocol is shown in Table XIII. TABLE XIII — Serialized user protocol short-message structure Bits U sage 26 Protocol flag (=1) 27-36 MID code (see § 2.2) - 37-39 User protocol type (= 011) 40-43 Satellite EPIRB type 44-63 Serial number 64-83 National use (see footnote to Table VII) 84-85 Auxiliary radio-locating device type(s) Bits 27 to 36 designate the country of satellite EPIRB registration. Bits 40 to 43 indicate the satellite EPIRB type as follows: 0000: aviation (i.e. aeronautical satellite EPIRB) 0100: maritime (i.e. float-free satellite EPIRB) 1000: survival (i.e. nonfloat-free satellite EPIRB) 1100: personal satellite EPIRB. Rec. 633-1 307 Bits 44 to 63 designate a serial ID code number from 0 to 1 048 575 (i.e. 220— 1) expressed in binary notation. Bits 64 to 83 are for national use and control but will be made public when assigned. 2.4.5 Radio call-sign user protocol (user protocol \ 10) The radio call-sign user protocol is intended to accomodate a radio call sign of up to seven characters where letters may be used only in the first four characters, thereby complying with the ITU practice on formation of radio call signs. The short-message structure of the radio call-sign user protocol is shown in Table XIV. TABLE XIV — Radio call-sign user protocol short-message'structure Bits U sage 26 Protocol flag (=1) 27-36 MID code (see § 2.2) , 37-39 User protocol type (= 110) , 40-75 Radio call sign 40-63 First 4 characters (modified Baudot) 64-75 Last 3 characters (binary-coded decimal) 76-81 Specific satellite EPIRB ' 82-83 Spare (=00) 84-85 Auxiliary radio-locating device type(s) Bits 27 to 36 designate the country of aircraft or vessel registration. Bits 40 to 75 contain the radio call sign of up to 7 caracters. Radio call signs of fewer than 7 characters should be left justified in the radio call-sign field (bits 40-75) and padded with “space” (1010) characters in the binary-coded decimal field (bits 64-75). Bits 76 to 81 are used to identify specific satellite EPIRBs on the same vessel or aircraft (the first or only float-free satellite EPIRB should be coded with a modified-Baudot zero (001101); additional satellite EPIRBs should be numbered consecutively using modified-Baudot characters 1 to 9 and A to Z). 2.4.6 Test user protocol (user protocol 111) The test user protocol is used for demonstrations, national tests, training exercises, etc. Mission control centres (MCCs) will not forward messages coded with this protocol unless requested by the nation conducting the test. The short-message structure of the test user protocol is shown in Table XV. TABLE XV — Test user protocol short-message structure Bits U sage 26 Protocol flag (=1) 27-36 M ID code (see § 2.2) 37-39 User protocol type (= 111) ' 40-83 National use 84-85 Auxiliary radio-locating device types 308 Rec. 633-1 Bits 27 to 36 designate the country of satellite EPIRB registration. Bits 40 to 83 are for national use. 3. Emergency-code/national-use field The emergency-code/national-use field consists of bits 107 to 112, which can be encoded with optional data described in § 3.1, 3.2 and 3.3. However, when neither the emergency code nor the national use has been implemented nor such data entered, the following default coding should be used for bits 107 to 112: 000000: for satellite EPIRBs that can be activated only manually, i.e. bit 108 = 0 (see below); 010000: for satellite EPIRBs that can be activated both manually and automatically, i.e. bit 108 = 1 (see below). Bit 107 is a flag bit that should be automatically set to (= 1) if emergency code data has been entered in bits 109 to 112, as defined in § 3.1 or 3.2. Bit 108 indicates the method of activation that has been built into the satellite EPIRB: — bit 108 set to (= 0) indicates that the satellite EPIRB is the type that can be activated only manually; — bit 108 set to (= 1) indicates that the satellite EPIRB is the type that can be activated both manually and automatically. 3.1 Maritime emergency-code users The emergency code is an optional feature that may be incorporated in a satellite EPIRB to permit the user to enter data in the emergency code field (bits 109 to 112) of any maritime protocol (i.e.maritime/location protocol, maritime user protocol, serialized user maritime and survival protocols, and radio call-sign user protocol). If data is entered in bits 109 to 112, then bit 107 should be automatically set to (= 1) and bits 109 to 112 should be set to an appropriate maritime emergency code shown in Table XVI. TABLE XVI — Maritime emergency codes in accordance with the modified (*) IMO nature of distress indications IMO Binary code U sage indication 1 0 0 0 1 Fire/explosion ' 2 0 0 1 0 F lood in g 3 0 0 1 1 C ollision 4 ' 0 1 0 0 G rounding 5 0 1 0 1 Listing, in danger of capsizing 6 0 1 1 0 S inking r - 7 0 1 1 1 Disabled arid adrift 8 0 0 0 0 Unspecified distress (') 9 1 0 0 0 Abandoning ship 1 0 0 1 to 1 1 1 1 Spare (could be used in future for assistance desired or other information to facilitate the rescue if necessary) (*) Modification applies only to “1111”, which is used as a “spare” instead of as the “test” code. (') If no emergency code data has been entered, bit 107 remains set to (= 0). Rec. 633-1 309 3.2 Non-maritime emergency-code users The emergency code is an optional feature that may be incorporated in a satellite EPIRB to permit the user to enter data in the emergency code field (bits 109 to 112) of any non-maritime protocol (i.e. aviation user protocol, serialized user aviation and personal protocols, or other spare protocols). If data is entered into bits 109 to 112, then bit 107 should be automatically set to (= 1) and bits 109 to 112 should be set to an appropriate non-maritime emergency code shown in Table XVII. TABLE XVII — Non-maritime emergency codes Bits Usage (') 109 No fire (= 0), fire (=1) 110 No medical help (=0); medical help required (= 1) 111 Not disabled (=0); disabled (=1) 112 Spare (=0) (’) If no emergency code data has been entered, bit 107 remains set to (= 0). 3.3 National users When bit 107 is set to (= 0), codes (0001) through (1111) for bits 109| to 112 may be used for national use and should be set in accordance with the protocol of an appropriate national authority. 4. Long message (optional) Long message format for maritime/location protocol us described in § 2.3.2. For all user protocols (bit 26 = 1), the optional long-message format permits additional information to be included in the essage as shown in Table XVIII. TABLE XVIII — User protocol long-message code for bits 113-114 Code Usage 00 Latitude/longitude flag 01 Spare 10 Spare 11 Spare 310 Rec. 633-1 For the location message type (i.e. bits 113-114 = 00), bits 115 to 144 inclusive are decoded as shown in Table XIX. TABLE XIX — User protocol long-message structure for bits 115-144 Bits U sage 115-121 Latitude (degrees) 122-127 Latitude (min) 128 0: N orth; 1: South 129-136 Longitude (degrees) 137-142 Longitude (min) 143 0: East; 1: W est 144 Even parity bit applied to bits 113-143 The message-format flag, bit 25, should be set to (== 0) for a short-message transmission, but it should be switched automatically to (= 1) when data is entered in bits 113 to 144 for the long-message transmission. This will require two separate BCH codes: one for use with message-format flag (=0) (short-message format) and one for use with message-format flag (= 1) (long-message format). Rec. 441-1 311 SECTION 8K: AERONAUTICAL MOBILE SERVICE (TERRESTRIAL) RECOMMENDATION 441-1 SIGNAL-TO-INTERFERENCE RATIOS AND MINIMUM FIELD STRENGTHS REQUIRED IN THE AERONAUTICAL MOBILE (R) SERVICE ABOVE 30 MHz (Question 1/8) , (1966-1982) The CCIR, CONSIDERING (a) that the World Administrative Radio Conference, Geneva, 1979, in Recommendation No. 64, invited the CCIR to continue its study of signal-to-noise ratios and minimum field strengths; (b) that there are partial data relating to interference protection ratios and minimum field strengths required in certain documents of the ITU; (c) that the International Civil Aviation Organization (ICAO) has adopted standards and recommended practices for the best use of VHF frequencies and the aeronautical service and the avoidance of harmful interference, - UNANIMOUSLY RECOMMENDS that the provisions made by the ICAO should be considered as adequate for the planning and protection of Aeronautical Mobile (R) Service frequencies above 30 MHz; the provisions are contained in Annex 10, Volume 1, Part II, § 4.1.5, to the Convention on International Civil Aviation. 312 Rec. 591-1 RECOMMENDATION 591-1 * COMPATIBILITY BETWEEN THE BROADCASTING SERVICE IN THE BAND OF ABOUT 87-108 MHz AND THE AERONAUTICAL SERVICES IN THE BAND 108-136 MHz** (Question 61/8) . (1982-1986) The CCIR, CONSIDERING (a) that high-powered FM broadcasting service operations in close geographic proximity to aerodrome facilities are at times incompatible with airborne ILS, VOR and VHF communications equipment utilizing those facilities, and that this is a widely recognized problem among many users of aviation facilities in the Northern Hemisphere of ITU Region 2 and parts of Region 1; . (b) that in accordance with RR No. 44, the aeronautical radionavigation service is “A radionavigation service intended for the benefit and for the safe operation of aircraft”; (c) that FM broadcasting transmitters employ power levels which are relatively much higher than aeronautical services transmitters; (d) that aeronautical radionavigation and communication receivers have varying degrees of signal sensitivity and susceptibility to interference; (e) that high power broadcasting transmissions may cause interference to airborne receivers, depending upon relative distance between the transmitter and receiver; (f) Recommendation No. 704 of the World Administrative Radio Conference (Geneva, 1979) (WARC-79) which addresses potential interference problems between the FM broadcasting service and the aeronautical radionavigation service; UNANIMOUSLY RECOMMENDS 1. that administrations be invited to advise the broadcasting and aviation communities of the potential FM broadcasting and aeronautical systems incompatibility problem; 2. that administrations develop or, where applicable, strengthen coordination procedures between the aviation and broadcasting communities to minimize future problems; 3. that Report 929 be used as the best available guidance to date on the above matters. * The Director, CCIR, is requested to bring this Recommendation to the attention of the International Civil Aviation Organization (ICAO) and Study Groups 1 and 10. ** This band will be expanded to 137 MHz by 1 January, 1990. SECTION 8L: AMATEUR SERVICE; AMATEUR SATELLITE SERVICE There are no Recommendations in this Section. PAGE INTENTIONALLY LEFT BLANK PAGE LAISSEE EN BLANC INTENTIONNELLEMENT Res. 20-5 315 RESOLUTIONS AND OPINIONS RESOLUTION 20-5 CHARACTERISTICS OF EQUIPMENT AND PRINCIPLES GOVERNING THE ALLOCATION OF FREQUENCY CHANNELS BETWEEN 25 AND 3000 MHz IN THE LAND MOBILE SERVICE (Question 7/8) (1959-1963-1966-1970-1974-1978-1990) The CCIR, CONSIDERING (a) that land mobile services of various kinds are developing rapidly; (b) that, in border areas, difficulties may arise between the services of different administrations; (c) that it would be advantageous if there were a sufficient measure of agreement, where necessary, between administrations on the characteristics of equipment and on the principles adopted in the planning for land mobile services, UNANIMOUSLY DECIDES 1. that administrations should consult together as necessary to resolve any difficulties concerning their land mobile services and for the purpose of improving such services; 2. that those administrations which are interested in the provision of common land mobile services should consult together and should advise the CCIR of any technical and operational problems that require international study; 3. that administrations should continue to submit new data regarding the measuring methods used in their respective countries to the Chairman, Study Group 8 and to the Director, CCIR, for circulation. The attention of administrations is drawn to the methods of measurement currently being standardized by the International Electrotechnical Commission (IEC) (see Opinion 42); 4. that administrations should submit information on practices adopted for the allocation of channels between 25 and 3000 MHz for land mobile services to the Chairman, Study Group 8 and the Director, CCIR, for circulation; 5. that administrations should submit details of the blocks of frequencies between 25 and 3000 MHz allocated: 5.1 for transmissions from base stations, and 5.2 for reception at base stations; 6. that administrations which have reached agreement with adjacent countries on the operation of land mobile services in border areas, should submit to the CCIR technical and operational details of the agreement to assist other administrations with similar problems. 316 Op. 42-2 OPINION 42-2 METHODS OF MEASUREMENT OF TECHNICAL CHARACTERISTICS OF EQUIPMENT FOR THE LAND MOBILE SERVICE BETWEEN 25 AND 3000 MHz (1970-1974-1990) The CCIR, CONSIDERING • (a) that it is desirable to interchange information of the requirements of administrations concerning the technical characteristics of equipment used in land mobile services between 25 and 3000 MHz; (b) that to facilitate the exchange of such information it is desirable to reach agreement on the methods to be adopted for the measurement of the technical characteristics; (c) that it is understood that the International Electrotechnical Commission (IEC) is studying methods of measurement, IS UNANIMOUSLY OF THE OPINION 1. that the IEC should be invited to advise the CCIR of any proposals they have made (or have under consideration) for the methods of measurement of the technical characteristics of transmitters and receivers which could be applied to radio equipment used in land mobile services; 2. that the Director, CCIR, should be invited to transmit this Opinion to the IEC. Note — Recommendation 478 indicates the technical characteristics considered of international importance. Op. 43-2 317 I OPINION 43-2 \ ' SELF-SUPPORTING ANTENNAS FOR USE ON BOARD SHIPS Performance at 500 kHz (1970-1974-1978) The CCIR, CONSIDERING (a) that an increasing number of ships are equipped with self-supporting antennas; (b) that the CCIR has studied the problems concerning self-supporting antennas and has collected data from measurements carried out by administrations (see Report 502 (Kyoto, 1978)); (c) that development work is taking place in several countries with the aim of improving the performance of such antennas; * (d) that further study is necessary, IS UNANIMOUSLY OF THE OPINION « 1. that the information given in Report 502 (Kyoto, 1978) demonstrates that the values in the table of metre-amperes in Chapter IV, Regulation 10 (g) of the International Convention for the Safety of Life at Sea, London, 1974, are not applicable to self-supporting antennas; 2. that a single metre-ampere table may not be sufficiently accurate for all types of self-supporting antennas and corrections should be made according to results obtained from series of field strength measurements on various ship installations, including each particular type of self-supporting antenna; 3. that from the results of tests available, the following additions to the above-mentioned table of metre-amperes could be made to include self-supporting antennas: TABLE I Normal range in nautical miles Metre-amperes (•) 200 305 - 175 . 215 150 150 125 110 100 85 > 75 55 (!) The product of the distance (in metres) from the highest part of the antenna to the deepest load water-line and the current (in amperes) measured at the base of the radiating portion of the antenna. 4. that for certain types of antennas such as the whip type shown in Fig. 18 of Report 502 (Kyoto, 1978), the metre-amperes values in the table shown in § 3 might be considerably higher; 5. that this Opinion, together with Report 502 (Kyoto, 1978), should be brought to the attention of the International Maritime Organization (IMO) by the Director, CCIR. 318 Op. 49-1 OPINION 49-1 METHOD OF MEASUREMENT OF MAN-MADE NOISE IN THE VARIOUS MOBILE SERVICES (1974-1978) The CCIR, CONSIDERING (a) that the CCIR has under study the signal-to-noise ratios and the minimum usable Field strengths required for satisfactory reception of the different classes of emission in the various mobile services; (b) that the minimum usable field strengths required are influenced by levels of ambient man-made noise; (c) that information on ambient man-made noise levels is necessary to further the present studies; (d) that the levels of man-made noise will vary with the distance from the source of that noise; (e) that the units in which man-made noise is measured should be the same as the units used in the determination of the degradation of performance of mobile radio receiving equipment; (f) that the degradation of performance of mobile radio receiving equipment appears to be dependent not only on the amplitude of such noise but also on the pulse repetition rate; (g) that the IEC have under consideration methods of measurement of degradation of performance of mobile radio receiving equipment due to man-made noise; and (h) that a uniform method of measurement and presentation of results is desirable to permit comparison of measurements made independently, IS UNANIMOUSLY OF THE OPINION 1. that the International Electrotechnical Commission (IEC) and the International Special Committee on Radio Interference (CISPR) should be invited to ' advise the CCIR of suitable methods of measuring the parameters of man-made noise; 2. that the methods proposed should include the definition of a reference antenna and a reference distance from noise sources; 3. that the IEC and the CISPR should advise the CCIR on the preferred units to be used in the measurement of noise parameters and degradation of performance by man-made noise. Note 1 — The Director, CCIR, is invited to draw the attention of the IEC and the CISPR to this Opinion. Note 2 — The Director, CCIR, is also invited to draw the attention of the Interim Working Party 6/2 to this Opinion. Op. 73 319 OPINION 73 INTERFERENCE DUE TO MAN-MADE NOISE IN THE VARIOUS MOBILE SERVICES (1982) The CCIR, CONSIDERING (a) that the CCIR has under study the signal-to-noise ratios and the minimum usable field strengths required for satisfactory reception of the different classes of emission in the various mobile services; .(b) that the minimum usable field strengths required are influenced by levels of ambient man-made noise; (c) that information on ambient man-made noise levels is necessary to further the present studies; '(d) that the International Electrotechnical Commission (IEC) has elaborated methods of measurement of degradation of performance of mobile radio receiving equipment due to man-made noise; (e) that the IEC has elaborated methods of measurement of man-made noise which are expressed in the same units as used in Considering (d); (f) that the International Special Committee on Radio Interference (CISPR) limits provides for measurements of ignition systems of motor vehicles in the frequency range 40-250 MHz, IS UNANIMOUSLY OF THE OPINION 1. that the IEC and the,CISPR should be invited to advise the CCIR as to the man-made radiation levels of motor vehicles complying with the CISPR limits when received by a base or mobile station antenna: 1.1 mounted on a vehicle radiating the noise, 1.2 mounted on a vehicle operated in traffic of from 100 to 10 000 vehicles per hour, 1.3 mounted at a base station in an area of traffic density of 10, 100, 1000 vehicles per km2, 1.4 mounted on an aircraft operating at altitudes of 1 km, 4 km and 10 km for traffic densities of 100 and 1000 vehicles per km? in an area below the aircraft; 2. that the IEC and the CISPR should be invited to advise the CCIR as to the degree of degradation to both analogue and digital communication systems caused by these noise levels.