receive Morse code by ear mentally without writing down the information at speeds up to 70 wpm. To write down the Morse code information manually at speeds higher than 20 wpm it is usual for the operators to use a typewriter or computer keyboard to enable higher speed copying. In the United States a commercial radiotelegraph operator's license is still issued, although there is almost no demand for it, since for long distance communication ships now use the satellite-based Global Maritime Distress and Safety System. Besides a written examination, proficiency at receiving Morse at 20 wpm plain language and 16 wpm in code groups must be demonstrated. High-speed telegraphy contests are still held. The fastest Morse code operator was Theodore Roosevelt McElroy copying at 75.6 wpm using a typewriter at the 1939 world championship. See also Colemak keyboard Dvorak keyboard Instructograph Keystroke dynamics Morse code Speed typing contest Touch typing References Input/output Reading (process) Typing Writing Units of temporal rate