<P> Morse code is a method of transmitting text information as a series of on - off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment . It is named for Samuel F.B. Morse, an inventor of the telegraph . The International Morse Code encodes the ISO basic Latin alphabet, some extra Latin letters, the Arabic numerals and a small set of punctuation and procedural signals (prosigns) as standardized sequences of short and long signals called "dots" and "dashes", or "dits" and "dahs", as in amateur radio practice . Because many non-English natural languages use more than the 26 Roman letters, extensions to the Morse alphabet exist for those languages . </P> <P> Each Morse code symbol represents either a text character (letter or numeral) or a prosign and is represented by a unique sequence of dots and dashes . The duration of a dash is three times the duration of a dot . Each dot or dash is followed by a short silence, equal to the dot duration . The letters of a word are separated by a space equal to three dots (one dash), and the words are separated by a space equal to seven dots . The dot duration is the basic unit of time measurement in code transmission . To increase the speed of the communication, the code was designed so that the length of each character in Morse varies approximately inversely to its frequency of occurrence in English . Thus the most common letter in English, the letter "E", has the shortest code, a single dot . </P> <P> Morse code is used by some amateur radio operators, although knowledge of and proficiency with it is no longer required for licensing in most countries . Pilots and air traffic controllers usually need only a cursory understanding . Aeronautical navigational aids, such as VORs and NDBs, constantly identify in Morse code . Compared to voice, Morse code is less sensitive to poor signal conditions, yet still comprehensible to humans without a decoding device . Morse is, therefore, a useful alternative to synthesized speech for sending automated data to skilled listeners on voice channels . Many amateur radio repeaters, for example, identify with Morse, even though they are used for voice communications . </P>

In morse code which letter is represented by a single dot