PXML No. 45
APPROVAL No. S/1207/3/C/021122


Tudor is a microprocessor controlled key telephone system with a maximum capacity of 5 exchange lines and 20 extensions, It comprises a free standing central control unit with wall mounted box connection and a range of 4 wire connected Keysystem terminals. Two wire extension telephones may also be provided in place of 4 wire terminals.  Two sealed batteries are supplied to provide basic system operation during power failures.
Introduced around 1983/1984.

Tudor was installed by BT in the former Midland and Scottish regions. BT has now withdrawn this product from their portfolio.

Made by GEC Plessey Telecommunications Ltd (GPT).
Marketed by Reliance Systems Ltd as the Keylink.
Marketed by BT Midland Region as the Tudor.

Approved for direct connection to the PSTN (loop disconnect signalling only) or by working as a (List A or D) subsidiary system (loop disconnect or MF signalling) connected to a (List C) PBX. The system will only support Earth Recall to host PBX.

SOFTWARE: The following software levels are approved for use are:-
Version 3 : Dated 31 January - 1984 (D140846/C or D140847/C (EPROM)
Version 4 : Dated 10 April - 1984 (Serial ringing) (D140846/D PROM & D140847/D EPROM)
Version 4 : Dated 19 April - 1984 (Parallel ringing) (D142390/A PROM & D142391/A EPROM)
The Issue level is shown on Eprom IC3 on the Processor Card.

Terminal types-
Terminals 30N (Mk I terminals) are only compatible with Subscribers card SP.
Terminals 34N (Mk II terminals) & 62N & 64N (Mk III terminals) are only compatible with Subscribers card TP.

When replacing a 30N terminal by any other type will also require replacing the subscriber card by a TP card (and changing the partner terminal as each subscriber card supports 2 extensions).
Where a TBL 30N terminal is deemed unrepairable or (unreplaceable) by GPT it will be replaced by two TEL 34N terminals and compatible extension line card for the repair price of a TEL 30N terminal.
Terminals 62N & 64N are electrically compatible with 34N terminals but are GPT badged and physically different to BT Tudor terminals and should not be used whilst TEL 30N or TBL 34N terminals are available.
Two wire terminals (TEL 33N) are not covered by this agreement and should be maintenance replaced by any basic LD signalling telephone (e.g. Statesman).

The BT Tudor Buy-Back scheme ended on 28th Feb 1992. The majority of Tudor systems were sold to customers and are hence the customer's property.

Maximum loop resistance from CPU to extension telephone is 250 ohms.

Height - 310mm
Width - 574mm
Depth - 315mm

Parts List


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Last revised: November 05, 2021