Telegraphist is an operator who uses the morse code

Morse code

Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...

 in order to communicate by land or radio

Radio

Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...

 lines. Telegraphists were indispensable at sea in the early day of Wireless Telegraphy

Wireless telegraphy

Wireless telegraphy is a historical term used today to apply to early radio telegraph communications techniques and practices, particularly those used during the first three decades of radio before the term radio came into use....

. During the Great War the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

enlisted many volunteers as Telegraphists. Telegraphists are also called Telegraph Operators. This job doesn't just use men but has used women equally.