Bakelite wall telephone for use in C.B. & Automatic exchange areas on PBX extensions, systems that require recall facilities and certain extension plans.

This telephone had provision for one button in the case moulding.

There was no call for this telephone so it was not released, the Telephone No. 321 being used instead.

Diagram for telephone circuit - N431.

Diagram for Button labels - N620.

History, Technical and General Information on 300 type telephones

300 Type telephone circuit description

Development of the Bakelite Wall Telephone

Collectors information

Keys for use in 300 type Wall and Table Telephones

How to restore Bakelite

Comparison chart of GPO 300 type telephones

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Last revised: February 19, 2023