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
Telegraph code Telegraph code A telegraph code is one of the character encodings used to transmit information through telegraphy machines. The most famous such code is Morse code. Morse code can be transmitted and received with very simple electrical equipment, such as the electrical telegraph invented in 1816. Morse code represents each letter of the alphabet as a series of "dots and dashes" (short and long bursts of electronically-generated noise). The speed of sending is directly related to the length of the shortest (dot) element: a dash is three dots long, an inter-character gap is the same length (3 dots), and inter-word