Morse code in Cayo Largo del Sur, Cuba is coded as "UCL", and UCL in Morse code is transmitted on its radio frequency. In some countries, during periods of maintenance, the facility may radiate a T-E-S-T code () or the code may be removed which tells pilots and navigators that the station is unreliable. In Canada, the identification is removed entirely to signify the navigation aid is not to be used. In the aviation service, Morse is typically sent at a very slow speed of about 5 words per minute. In the U.S., pilots do not actually have to know Morse to
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