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