Morse telegraph receiver. Historical illustration of the receiver of a telegraph machine used to communicate in Morse code. The messages arrived through wires as a series of long and short electrical pulses. Electromagnets attached to a printing head then converted these into dashes and dots. In Morse code, each letter and number is represented by a combination of dots and dashes. The code was printed on a stream of ticker tape, which was collected at far left. Morse sent the first telegraph message in 1844. Artwork from 'Les merveilles de la science' by Louis Figuier, 1878.