Telephone No. 262CB was a combined handset telephone and Repeater Telephonic (amplifier) for customers with weak voices.  The phone could be fitted with a dial if required.  The telephone is a modified Telephone No. 226.

The amplifier unit is secured beneath the telephone in the place normally occupied by the bell-set of a combined sot telephone and has a moulded cover similar to a bellset cover but modified to take the amplifier switching key.

The amplifier has a single stage employing a miniature directly-heated pentode type Hivak XY.  It is operated by dry batteries housed in a battery box which also contains a bias resistor and capacitor.  The degree of amplification is variable and controlled by a potentiometer mounted on a bracket fixed to the telephone cradle.

A Bellset No. 26 was used for the incoming ring and this would be mounted on an adjacent wall.

The battery box was installed close by.  The batteries required to operate the amplifier were:-
LV - 2 x Cells Leclanché DR2.
HV - Battery Dry No. 2.

Introduced circa 1952, but no indication of it's life span or uptake.

Wired to Diagram SA4117.

Circuit diagram - N362.

Drawing - 90347

Specification - D1944.

Superseded by Amplifier No. 143A which is used with a Telephone No. 710.

Additional Pictures

The test sets were made up using a Telephone No. 226.
Picture taken in 1937 at the GPO Laboratories at Dollis Hill, London


Picture taken in 1937 at the GPO Laboratories at Dollis Hill, London


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Last revised: December 11, 2022