Telegraph - Morse Code communication
The transmission of Morse Code over electrical wires is known as Telegraph and when it is sent wirelessly via radio it is known as Radio Telegraphy. Both involve a Morse key at the sending end to tap out the message and a receiving device at the receiving end which either converts the message into an audible tapping sound or into a punched /printed tape containing dots and dashes.
Telegraph transmitter
Date: c1900
Title: Morse key – sending device
Description: A telegraphic Morse key allows an operator to transmit coded signals between remote locations in the form of electrical pulses.. In the case of Telegraph these signals travel between locations via an electrical wire.
Telegraph Receiver
Date: c1880
Title: Telegraph Sounder - Air Ministry ref. number 10G/117 telegraph sounder.
Description: This type of receiver converts the Morse Code signal into audible sounds. In this instance the operator listens to the Morse signal as it is received and transcribes it directly into text.
Spark Gap Transmitter
Date: Unknown
Title: Spark Gap Transmitter
Description: Used for transmitting morse code as radio signals. Early radio transmitters used high voltage sparks to send Morse Coded messages as a series of pulses of radio waves. The very early radio transmitters operated by virtue of a spark arcing across a gap. This would generate pulses of electromagnetic radiation which could then be broadcast as radio waves via an aerial. Details of how Spark Gap Transmitters work can be found here
Film: Telegraphic services in early New Zealand
The following link is a short film produced by the New Zealand Post and Telegraph Department in the 1930’s describing the operations of telegraphic services at the time: From Back blocks To High Seas (AAOJ W3327/281)