Special fire telephone used in exchange buildings This is the later model called the Mk 4

Fire emergency phone for use in CB and Automatic exchanges.

The Mark 4 version consisted of a Telephone No. 232 mounted on a Bellset which in turn is mounted on a wooden box that houses batteries and a hand generator.  The hand generator is locked by means of a releasable metal bar.

The Mark 4 was introduced in 1938.

Telephone included (1928):-
1 x Bell, Magneto, 1000w.
1 x Coil, Induction, No. 3 or No. 14 .
3 x Condensers, M.C., No. 1.
2 x Cords, Instrument, No. 116.
1 x Cord, Instrument, No. 222.
1 x Frame, Notice, No. 1.
1 x Generator, N.T. No. 1001.
1 x Key, No. 72, red.
1 x Key-mounting V.
1 x Receiver, Bell, No. 1A.
1 x Transmitter, N.T. No. 13.
1 x Transmitter No. 1 and Adapter, transmitter, if used for maintenance.

Telephone included (1946 and 1956):-
1 x Bell-set No. 26.
1 x Glass No. 3.
1 x Cap, Lamp, No. 2-1C.
1 x Jack, Lamp, No. 10.
1 x Clip No. 31.
1 x Key No. 72, Red.
2 x Condenser, M.C., No. 102.
1 x Key-mounting, V.
1 x Cordage, Inst., No. 2/B, Brown, 18".
1 x Relay No. 503A.
1 x Relay-cover, AK.
1 x Frame, Notice, No. 1.
1 x Telephone No. 164, Black, with Cord, 3/63KB, 33".
1 x Generator. No. 26A with  adapter, generator, D 63018 and Handle, Generator, No. 15 (earlier supplies fitted with Generator No. 8A).
1 x Telephone No. 1/232CB, Incomplete (minus Base, Telephone No. 1/162).

To be requisitioned separately as required:-
3 x Cells, Leclanché, DS 5
1 x Lamp No. 2- ... V.

Circuit diagram - N181.
Diagram C.B. 1185.

Adjustment of Magneto bells

Telephone No 81 (Mark 4)

Looking down into the unit with the lid open

External view


Pictured above is the Telephone No. 103
It has an big generator which needed an enlarged cover

BACK Home page BT/GPO Telephones Search the Site Glossary of Telecom Terminology Quick Find All Telephone Systems

Last revised: March 02, 2021