TELEPHONE No. 19
Also known as the Post Office telephone for Granular Transmitter 'B' (GTB).
Wall type telephone with Deckert transmitter for use on CBS exchanges.
No more information, but it could be assumed that it is the same casing as
Telephone No. 17 and Telephone No. 21
but with differing circuitry.
Last revised: February 04, 2020