His father was a telegraphist for the post office, as was his mother before marriage.
From the en.wikipedia.org
By contrast, the dispatcher continues his express schedule of seductions, this time with the railroad telegraphist.
From the time.com
Born in Reading, in the middle of a snowstorm, she was the first child of Peggy, a housewife, and George, a post office telegraphist, and was followed seven years later by her sister, Pauline.
From the henleystandard.co.uk
More examples
Telegrapher: someone who transmits messages by telegraph
Telegraphist is an operator who uses the morse code in order to communicate by land or radio lines. Telegraphists were indispensable at sea in the early day of Wireless Telegraphy. During the Great War the Royal Navy enlisted many volunteers as Telegraphists. ...
Morse code operator who communicated radio or land lines.