Named for Morse, Samuel Finley Breese, the set of signals used on the Telegraph and in some Radio transmissions, or with a flash lamp for visible signaling. The unit of the
code is the dot, representing a very brief depression of the telegraph key. The
dash represents a depression three times as long as the dot. Different
combinations of dots and dashes are used to code the alphabet, the numerals 1 to 9 and
zero, the period, and the comma. American Morse differs considerably from
International Morse. Morse code is now mainly used by amateur (ham) radio operators.