Ringdown and Private Line Automatic Ringdown Channel Units Channel Ringdown Automatic Line and Privateringdown

Page 1

SECTION 365-170-119

Issue 1, February 1983

leads and convert to signaling logic for the to convert leads signaling and logic

Signaling is accomplished in the RD applica-

tion by pushingtion a button by at the calling station

Supervisionduring operations RD for both 2-

wire and 4-wire circuits wire 4-wirea propand by provided is

"S"

generates ringing current to the calling chan

2. CIRCUIT DESCRIPTION

other station out of a group of 15 on the onother stationsame bridge. 15 group of a of out

and circuit description numbers. (CD) Figures and 1

unit.

A. Signaling and RDand Supervision PLAR

2.01 Table A lists these units with their schematic (SD)

2 show a pictorial view of the of a pictorialeach component of side show view 2 the calling station. Options to convert the channel

both the 2-wire and 4-wire units. and 4-wire thethe Bothboth 2-wire and 2-wire

which nel unit. Signaling is accomplished in the PLAR ap plication by an off-hook condition (loop closure) at

unit to or type RD PLAR signaling are contained on

4-wire units, 4-wire optioned when in the PLAR pro mode, bursts and passes the appropriate signaling to logic

2-wire unit, 2-wire optioned in the PLAR also mode, offers the option of -72 volt talk battery.

2.02 (via switches) in each channel unit. During ringing,

erly conditioned (via microswitches) microcomputer contained in each channel unit. The calling RD optioned channel unit identifies the 20-Hz ringing bridge, the channel units receive -48 volt de pulses vide -48 vide talk volt battery to the metallic facility. The the D4 common circuits. The called RD optioned channel unit channel the from converts the signaling D4 logic common circuits into a ringing signal toward the called station depending on the selectedringing station on mode called depending

the called station channel unit produces de pulse

the calling station answers and a talking path is es tablished. For bidirectional signaling around a

on the on

which is sent to which the stationcalling channel unit until

2 NOTICE

Printed in U.S.A.

PAGE

DESCRIPTION

•

D4 CHANNEL BANK D4 CHANNEL

Not for use or disclosure outside the

channel units.

Bell System Bell except under written agreement

DIGIT AL TRANSMISSION SYSTEMS TRANSMISSION AL DIGIT

set to determine the

CONTENTS

Ringing Modes (Ringdown)

Transmitting Operation

Receiving Operation Receiving

Wheneverthis section is reissued the reason

This section describes the D4 2-wire and 4- Both the 2-wire and 4-wire units provide a nonswitched private line service. Each unit

for reissue in given be will this paragraph.

wire ringdown/private line automatic

RINGDOWN AND PRIVATE LINE AUTOMATIC RINGDOWN CHANNEL UNITS CHANNEL RINGDOWN AUTOMATIC LINE AND PRIVATERINGDOWN

A. Signaling and and RD PLAR Supervision REFERENCES

CIRCUIT OPTIONS CIRCUIT

TCo Standard TCo

1. GENERAL

2. DESCRIPTION CIRCUIT

BELL SYSTEM PRACTICES SYSTEM BELL

1. GENERAL 1.02

1.01 1.03

and channel PLAR units.

service channel units combine the RD and PLAR mode of -either operation, RD or PLAR. The PLAR The D4 channel units channel with are the compatibleD4 The mode RD The lines. 2-point to only applicable is mode is intended for multipoint bridged private lines and includes features to allow any station to select any

ringdown (RD/PLAR) channel units. These special contains options that can functions that separate were the in SECTION 365-170-119

D4 common circuits. The bridge provides the means limit is a nonselective ringing mode with a morse for connecting three or more stations together. Fig code type of signaling. The ringing button at the ure 3 illustrates a typical multipoint RD 4-station calling station is pushed as many times as the code bridge circuit. being generated. All receiving station channel units respond to the pushbutton signals of the call 2.03 Supervision during PLAR operations for both ing station with a 2-second limit on each pulse. 2-wire and 4-wire units is also provided by a This causes all receiving stations to ring simulta properly conditioned microcomputer contained in neously with a 2-second ring duration for every each channel unit. An off-hook condition (loop clo signal from the calling station. sure) at either station will cause the calling station PLAR optioned channel unit to convert the loop clo sure signal into appropriate signaling logic for the D4 (4) Repeat Input Timing (No Limit): The common circuits. The called station PLAR optioned repeat input timing mode is identical to the channel unit converts the signaling logic from the D4 input timing mode of (3) above except no time limit common circuits into a repeated ringing signal to is invoked by the receiving station channel unit; ward the called station. The called station rings with therefore, ringing time will vary depending on how 2 seconds on and 4 seconds off. The called station long the calling station ringing button is de channel unit produces a 440- and 480-Hz ringback pressed. This mode is the pref erred mode for tone which is sent to the calling station channel unit bridge signaling which connects two carrier sys until the called station answers and a talking path is tems together. established. Figure 4 illustrates typical 2-point PLAR circuits. C. Transmitting Operation B. Ringing Modes (Ringdown) 2.06 The transmit circuit of the 2-wire RD/PLAR 2.05 The 2-wire and 4-wire ringdown units have channel unit has a hybrid circuit to convert four different switch-selectable signaling from 2-wire to 4-wire transmission for bidirectional modes available to satisfy the need for selective and processing of voice circuits. The transmitting signal nonselective ringing. They are as follows: is amplified, level adjusted, and filtered. Following the filter, the signal is sampled by a gate that is con (1) Code Select: In this mode any combination trolled by the channel unit logic circuits. It is then of 15 station switches may be selected to desig passed to the D4 common equipment. nate the ringing code to which a specific station will respond. The calling station sends ringing bursts to the transmitting channel unit (the same 2.07 The transmit circuit of the 4-wire RD/PLAR number of bursts as the code assigned to the de has a balanced input transformer equipped sired station). The transmitting channel unit con with switched impedances of 150, 600, or 1200 ohms verts these bursts to the appropriate signaling and an equalizer with 15 dB of 1 kHz insertion gain. required by the D4 common equipment, and the The transmitting signal is equalized, amplified level receiving channel units compare the received code adjusted, and filtered. After being filtered, the ~ignal to their assigned code. When the codes match, the is sampled by a gate and sent to the D4 common receiving channel unit sends a single 2-second equipment. burst of ringing toward the associated called sta tion. D. Receiving Operation (2) No Code: This mode is a nonselective type of 2.08 The 2-wire and 4-wire RD/PLAR receive cir- ringing mode that causes all receiving stations cuits are similar. Each unit reconstructs the to ring simultaneously. Each receiving channel voice frequency (VF) waveform from the gated PAM unit in a multipoint bridge circuit responds to the sample in the receive active filter at +4 dB TLP. The release of the ringing button at a calling station output of the receive filter is attenuated and ampli with a single 2-second 20-Hz ringing burst to its fied to meet levels needed on the VF cable. The re station loop or a 2-second -48 volt de pulse to the ceived VF signal is put on the cable through a hybrid "S" leads. in 2-wire units or a balanced transformer with (3) Repeat Input Timing (2-Second Limit): switched impedances of 150, 600, or 1200 ohms in 4- The repeat input timing mode with 2-second wire units.

Page 2

Page Page 3

365-170-119 365-170-119

SECTION SECTION

TITLE TITLE

1, 1,

155 155

rier rier Engineering.

Application Application Engineering - Car

D4 Channel D4 Channel Bank Channel Units

sion sion Systems

Description Description - Digital Transmis

D4 D4 Channel Bank Channel Unit

Practices Practices (TOP)

D4 Channel Channel Bank-Task D4 Oriented

7C036 7C036

7C035 7C035

SD/CD NUMBER NUMBER SD/CD

SECTION SECTION

855-351-105 855-351-105

365-170-101 365-170-101

365-170-000 365-170-000

TABLE A A TABLE

J98726SP J98726SP

D4 2-/ 4-WIRE RD /PLAR CHANNEL UNITS UNITS CHANNEL /PLAR RD D4 4-WIRE 2-/

EQUIPMENT EQUIPMENT CODE EQUIPMENT

4RD/PLAR 4RD/PLAR

2RD/PLAR 2RD/PLAR J98726SN

with with the RD/PLAR channel units:

The The is following a list of sections associated

Options for Options the 2-wire and 4-wire RD/PLAR units units are on and Fig. 1 respectively. shown 2,

CIRCUIT OPTIONS OPTIONS CIRCUIT

4.01 4.01

4. 4. REFERENCES

ment ment for that circuit.

(CLRC) or or work order record docu details (CLRC) (WORD)

PLAR options. options. Options PLAR necessary for a cir specific cuit cuit will be listed on the circuit layout record card

tions tions and Table C lists and defines the 4-wire RD/

3.01 3.01

Table Table B lists and defines the 2-wire RD/PLAR op 3. 3. JS,·

J4,

J3,

MODE

RINGING

Repeat input timing (2-second limit) Code select

Repeat input timing (no limit)

ringing is used in RD or PLAR applications.

FUNCTION

TABLE B TABLE

Red

COLOR

White No code

White

of S6 (M) are set as follows for one of four ringing modes:

and J9 exposedforis applications. RD Blackarea of

SWITCH 2 SWITCH

JS,

2-WIRE RD/PLAR OPTIONS RD/PLAR 2-WIRE

Red

COLOR

White White

SWITCH 1 SWITCH

Two switches (1 and

selected by switches 1 through 7 on S7 and by 8 through 15 on S8, respectively. and J9 is exposed for PLAR applications. White area of J2 is exposed for nonlooped de signaling. White area of J2 is exposed when 20 Black area of J2 is exposed when de ringing is used in RD applications. White area of J6 is exposed for 48-volt battery and black area is exposed for 72-volt Transmit attenuator provides 0 to dB 16.5 of attenuation in steps of 0.1 dB. These switches select a for code the select code ringing through mode. 1 Codes are 15 battery. White area J3, J4, of Receive attenuator provides 0 to dB 16.5 of attenuation in steps of 0.1 dB.

OPTION

J4, JS, J9

8, J2 M'(l, AC,DC

87, 88

PLAR/RD

J2 F, J6 RCV,AT2 J3,

TRMT, ATl

SECTION 365-170-119 SECTION

Page 4

JS JS

Page Page 5

ISS 1, SECTION 365-170-119 365-170-119 1, SECTION ISS

RINGING RINGING MODE

selected selected for nonloaded cable.

is is

N N

dB dB in steps. 15

11 11

to to

O O

Repeat Repeat input timing (no limit)

No No code

Repeat Repeat input timing limit) (2-second

dB dB of attenuation in steps of dB. 0.1

FUNCTION FUNCTION

16.5 16.5

C C

to to

to to dB of 16.5 attenuation in steps of dB. 0.1

O O

TABLE TABLE

is exposed for RD applications. Black area of J3, J4, and and J4, J3, area applications. Black of for RD exposed is

Red Red

COLOR COLOR

JS JS

White White

White White select Code

SWITCH 2 2 SWITCH

4-WIRE RD/PLAR OPTIONS OPTIONS RD/PLAR 4-WIRE

Red Red

COLOR COLOR

White White

SWITCH 1 1 SWITCH

and and sides of the receive metallic facility. The open position disconnects the metallic

These switches allow selection of 150-, 600-, or 1200-ohm impedance impedance to or the 1200-ohm 600-, switches These allow transmit selection of 150-,

steps. steps.

Four Four adjust binary are to used weighted switches S3 of the bandwidth the response of

Receive attenuator attenuator Receive provides

equalizer equalizer (height Hz bump) of 3250 from

Four Four binary are weighted used S4 switches of to adjust the amplitude the response of

facility. facility.

equalizer Hz equalizer bump) (bandwidth from of 3250 approximately Hz to kHz 200 3.4 in 15

Four Four binary weighted switches of S2 are used to adjust the slope of the equalizer

Part Part of switch S2 is used to make an overall slope adjustment to the equalizer fre

Transmit Transmit attenuator provides

frequency frequency response in steps 15 for loaded and nonloaded cable. White White area of J2 is for exposed de nonlooped signaling.

applications. applications.

quency response. response. L quency is selected for cable and loaded

White area of J3, J4, and and J4, White area J3, of

Black Black area of J2 is when exposed de ringing is used in RD applications.

White White area Hz ringing J2 of 20 is when used is in or exposed PLAR applications. RD

selected selected by switches 1 through 7 on S7 and by 8 through on 15 S8, respectively.

White White area J5 of for is exposed PLAR applications and black area for is exposed RD

is is for exposed PLAR applications.

These switches select a code for the code select ringing mode. Codes 1 through through These switches for 1 select select the are ringing code Codes a code 15 mode.

Two switches switches Two (1 and 2) of S6 are (M) set as follows for one of four ringing modes:

S1 S1

OPTION OPTION

dB, J5 J5 dB,

J2 J2

RCV, S5 S5 RCV,

TRMT, TRMT,

BW,83 BW,83

HT, HT, S4

SL,S2 SL,S2

RCV,AT2 RCV,AT2

s, s,

-7 -7

L/N, L/N, S2

PLAR/RD PLAR/RD

TRMT, ATl ATl TRMT,

AC,DC AC,DC

S7, S8 S8 S7,

J3, J3, J4, JS

J2 J2 M M 2) (1, "'

1£\l

1lffl

(AT1) (AT2)

Channel Unit

RD/PLAR

1-2-Wire

Fig.

SECTION 365-170-119 SECTION

Page6 7

Page

ISS 1, SECTION 365-170-119ISS1, SECTION

-71B

Channel Unit

RD/PLAR

5¥u

2-4-Wire

Fig. SECTION365-170.119

STATION EQUIPPIENT 'f....

STATION13

T1 LINE

D4 COPlfflN 4WRD/PLAR RD

2 4 .... 4 2 w D 1J w 'f 'f w D D w 4 4 ....: 4 4 R R S1 S1 R R T-R 0 C T1 LINE C D T-R T-R D C T1 LINE C D T-R I 0 0 I BRIDGE I 0 0 I p p T1-R1 T1-R1 p fll p L " " L L "fll L A "D "0 A A "0 0 A R N N R R N N R (RD) (RD) (RO) (RD)

fllETALLIC STATION FACILITY STATION EQUIPIENT TERNINAL EQUIPftENT

Q: a:I ...... I .,... STATION#2

STATION EQUIPftENT

STATION11 STATION#4 'f 'f.... .:.______

Fig. 3- Typical Multipoint Ringdown 4-Station Bridge Circuit

Page 8

'° '°

I I

,0 ,0

......

ca ca • •

......

D D CD CD

Fig. 4-Typical 2-Point RD/PLAR Circuits Circuits RD/PLAR 2-Point 4-Typical Fig. 9 9

D D

"'Cl "'Cl

,0 ,0 .,, .,, ......

°' °' I I UI UI

B. ANALOG AND DIGITAL CARRIER LINKS IN IN LINKS CARRIER DIGITAL AND ANALOG B.

TANDEM TANDEM w w

z z

6 6 a a

EXTENSION EXTENSION RANGE RANGE

Bi Bi F9

END END END END

STATION CARRIER OFFICE OFFICE CARRIER STATION

PLAR PLAR PLAR PLAR

EXCHANGE EXCHANGE EXCHANGE EXCHANGE

D4 D4 D4 D4

tj tj

FOREIGN ANALOG FOREIGN FOREIGN ANALOG FOREIGN

f--5 f--5

~ ~ F-SIGIALINI F-SIGIALINI F-SIGIALING F-SIGIALING

A. SINGLET CARRIER LINK LINK CARRIER SINGLET A.

RINGING RINGING LOOPCLOSURE LOOPCLOSURE

LOOPCLOSURE LOOPCLOSURE RINGING RINGING

4-WIRE 4-WIRE

OR OR 2- PLAR PLAR

PLAR PLAR

03 03 OR D4 D4 OR

T CARRIER CARRIER T

D4 D4

------OR OR METALLIC METALLIC 2- FACILITY------4-WIRE 4-WIRE