Telephone Repeater

r . , , -. ~ .. - ' ..- . ,;:· ; ·; .·-~ I ··, ·, .{ ...... - ,. \: ••· .'}f '---:. !\ ' . ' 111-'..!_..,.,,;..;: ...-.. ..... ' ·• , I ~:-U;. '- .~~ ... ~.<-I -~ I r··· i..:'t '.. --~ INSTRUCTION BULLETIN FOR TELEPHONE REPEATER-<P-7 Signal Corps, U. S. Army Order No. 12930 - Phila. - 42 FORT MONMOUTH SIGNAL CORPS PUBLICATIONS AGENCY FOR REFERENCE ONLY DO NOT TAKE FROM THIS ROOM • BY ORDER OF THE DIRECTOR n4- F't. Mon.- J2-4-43-5M--HQ ~~~~~~~~e_ MANUF ACTUBED BY !ntcrnational retepltone ~ J<adio ;Mfg. eorp. UNITED STATES OF AMERICA INSTRUCTION BULLETIN FOR TELEPHONE REPEATER TP-7 Signal Corps, U. S. Army Order No. 12930 - Phila. - 42 MANUFACTURED BY JJtterJtatioJta! retepltoJte .t J(adio ;tlfp. eorp. UNITED STATES OF AMERICA I October 15, 1942 CONTENTS Section Subj ect Page General .................................................................. ....... 2 Mechan ical Description 2. 1 l ~epeate r U nit ............. .................... ............ ................. 2.2 Power U ni t .................................. .. .............................. 2 2.3 !\ ssem b Ie d Units ---- -·- ·····················---·-·--- ········-········-- 2 3 Circuit D escription 3. 1 I ~ cpea ter Unit ................. ............................................. 2 3.2 l)o wer Unit ............................ ...................................... 5 4 O peration 4.1 General .................................................. ........................ 5 4.2 ·Power Connections ..................... ............................... 6 4.3 Line Connections ........................................................ 7 4.4 Circui t Operation ...................................................... 7 4.5 Monitori ng and Talking .. ................................... ....... 7 4.fi ~ ignalli ng .................................................................... 8 5 Parts l ist 5. 1 T elephone Repeater TP-7... ..................................... 8 5.2 W93-22 T elephone Repeater U ni t................ .... .. ...... 8 5.3 W93-23 Power Unit .................................................. 10 5.4 W93-21 Outer Case Equi pped with Spares ............ 11 5.5 W93-11 A. C. Mains Power Cable ..... ....................... 11 5.6 W93-12 Current Supply Cable ................................ 11 LIST OF PHOTOGRAPHS AND DRAWINGS Figure Subject Page Repeater Unit without Dust Co ver (Back View)____ 12 2 Repeater U nit without Dust Cover (Front View).. 13 3 Repeater Unit -- ---- -- -------- ----'- --- ------- --- -- ----- -- ------ ------------- --- 14 4 Relay Rack Mounting of Telephone Repeater T P-7 15 Sa ] ower Unit 16 Sb Power Unit without Dust Cover__ _____ ___ _____ ____ ______ _______ 17 Ga Telep hone Repeater with Case Cover open________ ____ ____ 18 ob T eleph one Repeater with Case Co ver cl osed___ __ _______ 19 7a Typical Four Wire Circuit___ ___ __ _____ __ __ __ ___ _______ ______ _______ __ 20 7b Transform er Connection s at the Vari ous Impedance Switch Positions -- -- ------ ----------- ---- ----- -- ------------ -------------- 21 8 Simplifi ed Schematic Diagram of Amplifier._____ __ ______ 22 9 Co nn ec tions for Impedance Switches S-1 and S-2.. __ 23 10 Circuits of Equalization for E ach Position of Switch 24 11 Frequ ency Curves of Repeater and Cabl e__ ________________ 25 12 Schematic of Power Unit_____ __ __________ _______________________________ 26 13 Panels for Repeater Showing Cabl e Co nnections______ 27 14 Co nn ec tions for T alking and Monitoring __ ____ __ ____________ 28 15 Schematic Circuit of T elephone Repeater 1 P -7__ ____ __ 29 TELEPHONE REPEATER TP-7 1. GENERAL Telephone repeater TP-7 is intended to use on fo ur wire Jin es either as a throug h or a termin al repeater. It is arranged f r portable field use or for mounting on a relay rack in an office. It consists essentially of two two-stage amplifi ers arranged o t hat the in puts and outputs can be switched to present either 300 ohm or 1200 ohm im pedance to the line as req uired or 600 ohm impedance w hen used a a terminal repeater. In order to compensate for variation of the transmission los w ith frequency over the lin e, an eq uali zer w hi ch can I e switched is provided. The switched positions make possible a fl at o·ain freq uency characteristic or one which slopes to compensate for diffe rent lengths of lin e. Each am pli fier has an operatin g gain of about 35 db at 1000 cycl es per second irrespective of the eq uali zer setting. Under normal opera ting conditions the re1 eater i capable of handling a power level of + 20 dbm. A power unit is provided, which suppli e the req uired power for operatin g the re1 eater from either the A. mains or from a 12 volt battery with a 100 cycl e per second vibrator. In addition, a means is provid e I so that the power may be obtain ed from local 24- 130 v bat teri es. T he current drain s for these methods of supplyin g power are as foll ows: Power ·~t jJJJl ·y Voltage C~ot ?Tent A. C. (Line) 110 110 milliamperes A. (Lin e) 220 55 milliamperes Battery 12 1 ampere Office Battery 24 150 m iII iam peres Office Battery 130 20 milliamperes 2. MECHANICAL DESCRIPTION 2.1 Repeater Unit T he repeater unit compri ses a chassis type assembly 17" x 5% 6" x 3~" as shown in photographs F ig. 1 and Fig. 2. This chassis has mounted on it the co mponent parts of the two amplifiers and is enclosed in a metal dust cover, as hown in protograph F ig. 3. The location of the necessary gain controls, witches and terminals fo r making the con nections to the lin e. for operatin g the repeater are hown in the upper panel of the rack moun ted repeater a· in photograph Fig. 4. T he eq uipment fo r each ampli fier occupies one half the length of the chassis. T he e 1uali zer coil , input and output coil an l gain control with associated switches are mounted in this ·equence from either end toward the center. T he two tubes of each a mplifier are mounted in a w ell left and ri g ht of the vertical center lin e and are covered by a removable plate so that they are readil y accessibl e. A plug is mounted on th e bottom of the chassis for making the power connections by means of the special cable supplied with the repeater. 2.2 Power Unit The equipment for the power supply is as ·embled on a chassis similar in design to the repeater unit as shown in photographs F ig. Sa and Fig. Sb and in the bottom panel of Fig. 4. It contain s the power transformer, rectifier and fi ltering arrangemen ts for operatino" lhe heat ers and plates of the tubes in the repeater from A. mains. W hen a 12 vo lt torage battery is the source of power, it i · used in conjuncti n with a 100 c. p. s. vibrator to energize the tran former feeding the recti fier. Under thi condition the heaters of the vacuum tubes are operated directly from the I attery. T erminals, fuses and switches arc mounted on the panel of the chassis assembly. A plug for connecting power to th e repeater is moun ted on the bottom of the chassis. 2.3 Assembled Units Both the repealer and the power unit have brackets at ll1c ends so that th ey can l.)e mou nted on a relay rack as shown in Fig. 4 o r in a case as shown in F ig. 6a. A wooden case is provid ed for mounting both the repeater unit and the power unit. This case is 20" x 8" x 9;;.;1." and is eq uipped with straps so that it is readily portable, as ·hown in photo graphs F ig. 6a and 6b . T he case with rq eater and power unit mounted in it weighs about 38 pounds. When the cover is opene l, lhe terminals, switches and co ntrols are exposed so that they are readily available f r making con nections and operation, as shown in photograr h Fig. 6a. The power from the power unit is ·upplied to the repeater unit by means of a cabl e with a socket on each end, which ma tches the plu g mounted on the uni t·. Two spare tubes, two spare fuses, a socket fo r connectin g the repeater to a 24 v - 130 v supply, a spare vibrator and a pare socket to fit th e plug marked A. ·.Main are mounted in the cover of th case. When the repeater and power unit are m unted together on a relay rack, the same cabl e with sockets on each end as is used with the case may be used for making the co nn ection to supply the power to the re peater unit, otherwise a longer cable between plugs will be required. In case the repeater is install ed where the office batteries are available for operatin a it, either on an emergency basis or in place of the power unit, a socket i provided which fi.ts the plu g in the repeater a nd can be wired so that the proper co nnections can be rea lily made to the batteries, as shown in F ig. 12. T his socket is mounted in the cover with the spare parts. 3. CIRCUIT DESCRIPTION 3.1 Repeater Unit The repeater unit consists of two amplifiers, with an equalizer for each and 3 position switches to change the gain frequency characteristic from Aat to different slopes to compensate fo r lin e conditions. Switches are also provided to chan ge the input and output impedance of the am plifi ers from 300 to 1200 ohms and to con nec t the input of one amplifier and the output of the other to a two-wire 600 ohm connection for ter minal use. The diagrams of Fig. 7b show the different arrangements pos sible when this repeater is connected on a four-wire line.

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