BT SENATOR (MERLIN S4022)

PXML No. 83
APPROVAL No.

Manufactured by GEC the Senator system came as a Mk1 or Mk2 system and both had an ultimate configuration of 5+10. When the Merlin trading arm of BT took over marketing of business systems the Senator Mk 2 became the S4022. The Senator system case was wall mounted and had an integral MDF. Adaptors could be supplied to cover 2 wire external extensions, inter PBX circuits and extension bells. These adaptors would be wall mounted along side the system box. A speed dialler called the Autodial 5000 was introduced and this was the same model as the Tyne autodial.

The terminals used are the same ones used on the Ambassador system but a 10 memory type (Telephone 8550) was introduced that was not sold as a Senator terminal.  These telephones are connected by four wires to the CCU are are connected via PST sockets.  The style of telephone was changed in  the mid to late eighties, away from the generic Ambassador telephone style.  The later Ambassador/Senator system telephone is shown on the right.
 

LD POT phones with Earth Recall can be fitted via an External Extension Adapter ESS10253.

Senator cannot be used on PBX's which use "C" wire signalling or timed break recall.

Power consumption - 200 watts

See also Ambassador

Go to Ambassador/Senator telephones page

Extension Socket Wiring (secondary sockets only)

System Options
DPA1210A LD Intercom Card to make system pulse dial
DPA1217A MF Intercom Card to make system tone dial
ESS10253 External Extension Adapter to allow connection of standard telephones.
ESS10255 External Bell Adapter to allow connection of additional bells.

Senator ESS10253 - External extension adaptor

Senator with front cover removed

In the picture above:-
Clear handle = Intercom card
Blue handle = Exchange line card
Yellow handle = Extension card

CPU Card Codes
MF cards have the code 80
LD cards have the code 77/A

Fuses
Fuses used on this system are BT types:- 36A/0.05, 72/0.5, 72/5, 73/0.1 & 73/4.

KNOWN ISSUES

INTER-PBX ADAPTOR (SA10254) USED ON SENATOR 1 SYSTEMS (JULY 1994)
A problem was highlighted when engineers were experiencing difficulty with an inter PBX circuit which kept locking up between a Senator and a Pentara when calls were extended over it. The problem did not exist prior to the adaptor being changed due to a lightning strike. This was eventually cleared by changing the Senator backplane, and therefore the software, to Senator 2.

The reason for this is that all adaptors (I/C 374225) now include an additional circuit board (marked DPA1383) that replaces the original plug-in IC. This has software that offers full DC5 signalling conditions when used with Senator 2 systems but is not to be used with Senator 1. Field staff should be aware of this problem to ensure that Inter-PBX adaptors are not changed out unnecessarily.

PARTS LIST

Last revised: November 04, 2021