Telegraph key and relay. The key was used for the transmission of signals in the Morse electric telegraph system. The relay was part of part of the circuit involved in receiving signals coming in from the telegraph line.

To transmit signals the operator depressed a pivoted metal lever (the key) to complete an electric circuit and transmit current along the telegraph line. Releasing the key broke the circuit and cut off the current. Letters and numbers were represented by a sequence of short and long current pulses, transmitted according to a defined code. The most widely used code was generally known as "Morse code".

When receiving signals, the current pulses coming in from the telegraph line activated the relay. From the relay, the signals could pass to a register and be displayed as long and short marks on a paper tape, or could be interpreted by an operator listening to the sounds made by the receiving instrument.

With marks of the Victorian Telegraph Service, which operated the telegraph system in Victoria from 1854 to 1869. Used at Melbourne Observatory.


This telegraph key and relay is one of the few objects in the telegraph collection that was used by the Victorian Telegraph Service which functioned between 1854 and 1869.

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