Relay used at telegraph receiving stations, particularly those operating on long connecting lines. Often signals received over long lines were too weak to operate the receiving instruments directly so the relay served as a very sensitive switch to connect a local battery to the receiving instruments.

This type of relay was used by the Australian Post Office in the 1920s.

Physical Description

Wooden baseboard. Relay with two horizontal coils on metal baseplate fitted to on end of baseboard. Baseboard also carries junction box to which is connected cable approximately1.6 m long fiited with plug with two jacks. Connecting wires beneath baseboard lead from relay to where another component was fitted but which is now missing.

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