Introduced in 1939 this is a combined table handset telephone used by the BPO in both C.B. and Automatic exchange areas.

This telephone has a DC Trembler bell, with one bell gong only and provision in the Bakelite case for three press buttons.

The bell was for intercommunication only and would have rung on an incoming exchange call.

Detail as for Telephone No. 326, Black, minus Cord, except  the Cradle-switch action is 2M and lC, instead of 2M.

Used on extension plans that require an additional gravity switch hook springset.

Mark 1 - has a receiver, Inset No. 1L in the handset.
Mark 2 - has a receiver, Inset No. 2P in the handset.
Mark 2A - has a receiver, Inset No. 2P in the handset with a switch hook bracket and plungers of an improved design.

Early models may be found with a Filter, Suppression No. 6 and a Coil, Induction No. 22 fitted.

Spring 1 of the cradle switch is spring-set is adjacent to the mounting.

Telephone includes:-
1 x Bell No. 65A, Unmounted.
1 x Part No. 3/SCA/17, Black.
1 x Bell-gong No.2, Nickelled.
1 x Capacitor, M.C. No. 97.
1 x Filter, Suppression No. 26A.
1 x Telephone No. 164, Black.
1 x Coil, Induction No. 27.
1 x Tray, D 62076, Black or Tray, D1/62833, Black or Tray, Dummy, D62099, Black.
1 x Dial, Automatic, Dummy No.3, Black (on CB variant).

Diagram for telephone circuit - N406.

Diagram for Button labels - N620.

Drawing No. 63022 - Telephone components parts.
Drawing No. 63023 - Chassis components.
Drawing No. 63250 - Chassis components (improved switch hook buttons).
Drawing No. 90319 - Telephone parts (Mk 3A).
Drawing No. 90373 - Chassis components (improved switch hook buttons).
Drawing No. SBA12 - 300 type base plate.
Drawing No. SCA17 - 300 type complete case.
Drwaing No. SCA20 - 300 type case.
Drawing No. SCA47 - 300 type complete case (improved switch hook buttons).

How to wire your Telephone No. 306 to make it work on Plug and Socket

300 Type telephone circuit description

Dismantling the Telephone No. 306

Dismantling the Handset

History, Technical and General Information on 300 type telephones

Collectors information

Adjustment of Magneto bells

Keys for use in 300 type wall and table telephones

Lamp Fittings

Labels that fit in the sliding tray

General fault finding on your phone

How to restore Bakelite

Comparison chart of GPO 300 type telephones


Typical 300 type chassis showing dial cord wiring connections



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

Last revised: February 19, 2023