International Morse Code

A standardised method of representing letters, numerals and punctuation as sequences of short and long signals.

The signals are commonly written as dots and dashes and can be sent by sound, light, radio keying or another medium in which short and long elements can be distinguished. The spacing between elements, characters and words is part of the code.

Morse code has a long history in maritime communication and can still be encountered in light signals, identifiers and distress signalling. The sequence three short, three long and three short signals represents SOS; its use as a distress signal is separate from the spoken radiotelephony word “Mayday”.