Subs Line Unit - 71200

The Subs Line unit (SLU) has 5 Line circuits and a 5x5 'A 'switch

1A1/71200

Location of A switch and LR and K Relays 

Y side of plug in unit

Picture of first generation Plessey Subs Line card taken from 1965 Publication 'PENTEX'

A SMALL ELECTRONIC EXCHANGE

Also from the 1965 Pentex  publication

Figure 18-Subscribers' Line Unit and 5 x 5 'A' Switch. (Three-quarter rear view) Also from the 1965 Pentex  publication


T71200.PTL - Issue 01

PATW_____712000_________________7.pdf

Wiring Notes

1 . DESCRIPTION.

 This document specifies TXE2 exchange equipment commonly referred to as

AT 71200 which was first used on MKl exchanges. The circuit consists of 1

unit and is constructed to T11000 equipment practice. The circuit is described

as a Subscribers Line Circuit and 'A' Switch.

2. DOCUMENTATION.

2.1 Contractual Documentation. In addition to this specification the

following documents shall de·termine the Post Office requirements for manufacture

and supply purposes.

2.1.1 Unit 1.


ITEM DOCUMENT CONTENT ISSUE CONTROL SIZE PURPOSE

01 700801/S PTL Circuit Diagram 3A PTL,R A1 C,M

02 700801/W PTL Physical Layout 07 PTL,R A1 C,M

03 700801/U PTL Upt Layout 09 PTL,R A3 C,M

ISSUE: P = Provisional;

CONTROL: D = On file for distribution; R = Restricted; U = Unsuitable

SIZE: Ax = Isometric size; I = Imperial; M = Microfilmed

PURPOSE: C = P&S Contractual; S = Service; M =Manufacture; I = Information

Shelf Wiring

Uf - not fitted on subs card

Back Plane Connector Summary

Line 1-5 : for connection to subs telephone A, B and Meter - Do i need to connect anything to Meter wire ?

A Switch Outlet A-E : for connecting to B switches - ABPH, where P is meter H is signal for holding path through Crosspoint switch relays. - for my TXE2 I only have 1B switch and 2 subs cards - so how do i connect ?

MK1 - MK5 : Input : Mark signal for each subs line - connects KT(A) & KT(B) to 'marked' sub

KT- K Test: Output:  - enables call control to know state of line selected by MK signal above

Free - 530 ohms to -48v ( 530 is 1.5k and 820 ohms in parallel) 

Parked - 1.5k ohms to -48v

Busy - earth ( when K relay is energised by P signal) 



Power Pins


Purple - A1 -50v pwr

 Grey/Red -A2 

NOT FITTED

NOT FITTED

Wht/Ora- A5 - Earth pwr

Gry/Brwn- A6 - 

NOT FITTED

NOT FITTED

A9 +50v pwr

A10

NOT FITTED

NOT FITTED

red- A13 - frame eth

GRN/RED -A14 -

NOT FITTED

NOT FITTED


TXE2 SIGNALS