Morse code

The Morse telegraph and workable code was first demonstrated in 1844. When a message was received, a series of short or long dashes (‘dots’ and ‘dashes’) were recorded onto a moving strip of paper. The pattern of the dots and dashes could be interpreted using Morse's Alphabetical Code.

International code for transmitting messages by wire or radio using signals of short (dots) and long (dashes) duration, originated by US inventor Samuel Morse for use on his invention, the telegraph (see telegraphy).

The letters SOS (3 short, 3 long, 3 short) form the international distress signal, being distinctive and easily transmitted (popularly but erroneously save our souls). Its use was discontinued in 1997. By radio telephone the distress call is ‘Mayday’, for similar reasons (popularly alleged to derive from French m'aidez, help me).