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 Mk 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 bar.

The Mark 4 was introduced in 1938.

Circuit diagram - N181.

Adjustment of Magneto bells

Picture is a Mk4 - looking down into the unit with the lid open

Pictured below is the Telephone No. 103
It has an big generator which needs an enlarged cover


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Last revised: December 02, 2018