Carbon granule transmitter introduced in the early 1930's and used in all bakelite handsets, later Candlesticks and some early 700 types.

Superseded by Transmitter No. 13.
 

Carbon granule transmitter used in all bakelite handsets and some early 700 types.

Superseded by the Transmitter No. 16 for 700 type telephones.
 

Carbon granule transmitter used in Trimphones and headsets.

The rubber grommet on the front is removed when used in Trimphones.

Carbon granule transmitter in general use from around 1960.  Superseded by the Transmitter No. 21.

Click here for a description of the transmitter

Two types available.

Introduced Oct 1982