English: Radio operator in the radio room of the German ocean liner SS Deutschland probably in 1914, showing the early Marconi wireless telegraphy equipment. On the right is the spark transmitter, consisting of an induction coil, Leyden jar capacitors behind it, spark gap, and an oscillation transformer ("jigger") inside the wooden box on the wall. The operator transmitted information by tapping on a switch called a telegraph key (visible behind coil) which turned the spark on and off, transmitting pulses of radio waves to spell out text messages in Morse code. On the left is the receiver, which recorded Morse code messages with an ink line on paper tape, which the operator later translated into text.
The equipment was produced by the Marconi Wireless Telegraph Co and the radio operator was also an employee. British-Italian entrepreneur Guglielmo Marconi invented the first practical radio transmitters and receivers in 1896. The first major use of radio was on ships, to keep in touch with the shore and call for rescue in emergencies, and Marconi's company dominated the marine wireless industry throughout the spark era until the 1920s, to the degree that the ship radio room was called the "Marconi room".