Morse code most common letter in English, the letter "E", has the shortest code: a single dot. Because the Morse code elements are specified by proportion rather than specific time durations, the code is usually transmitted at the highest rate that the receiver is capable of decoding. The Morse code transmission rate ("speed") is specified in "groups per minute", commonly referred to as "words per minute". Morse code is usually transmitted by on-off keying of an information carrying medium such as electric current, radio waves, visible light or sound waves. The current or wave is present during time period of the dot
History of the alphabet French/American one-handed alphabets retain the forms of the Latin alphabet, as the Indian manual alphabet does Devanagari, and the Korean does Hangul), Braille, semaphore, maritime signal flags, and the Morse codes are essentially arbitrary geometric forms. The shapes of the English Braille and semaphore letters, for example, are derived from the alphabetic order of the Latin alphabet, but not from the graphic forms of the letters themselves. Most modern forms of shorthand are also unrelated to the alphabet, generally transcribing sounds instead of letters. History of the alphabet The history of alphabetic writing goes back to the consonantal writing system