POST OFFICE RELAY TYPE G, 1920's

Used in telegraphy systems to amplify power and and enable equipment to be powered locally. Post Office Relay 'G' on a pluggable base.

The 'G' Relay is a later model of the Gulstad Relay see item A0238. It works best in Duplex Systems. "Duplex working consists in the simultaneous transmission of two messages in opposite directions over a single wire connecting two stations "(sic) P249 Telegraphy T.E. Herbert 1906 see item A0252 for types of telegraphy relays.
Suitable for use on a single needle telegraph or double plate sounder. It has double throw contacts and is polarised, (has a magnet).

A0253