It also began sending voice information to help pilots navigate, first by radiotelegraphy and then by teletypewriter.
Coast and ship stations transmitting radiotelegraphy.
In the early days of amateur radio, radiotelegraphy was the primary communication mode of all radio operators, including amateurs.
British Dictionary definitions for radiotelegraphy
a type of telegraphy in which messages (usually in Morse code) are transmitted by radio waves; its use is no longer widespread as it has been superseded by satellite technology Also called wireless telegraphy