Morse code is a type of character encoding that transmits telegraphic information using rhythm. Morse code uses a standardised sequence of short and long elements to represent the letters, numerals, punctuation and special characters of a given message.
Originally created for Samuel F. B. Morse's electric telegraph in the early 1840s, Morse code was also extensively used for early radio communication beginning in the 1890s.
Military ships, including those of the US Navy, have long used signal lamps to exchange messages in Morse code. Modern use continues, in part, as a way to communicate while maintaining radio silence. An important application is signalling for help through SOS, '. . . - - - . . . '. This can be sent many ways: keying a radio on and off, flashing a mirror, toggling a flashlight and other similar methods.
Regulations in 1987 replaced Morse code with the Global Maritime Distress Safety System (GMDSS) and came into force from 1st February 1992.