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
American Morse code 1851. It was necessary to have a common code as the Union had also agreed to direct connection of cables across borders (as opposed to recoding and retransmission by an operator). The code was adopted as the European standard in 1865, and was known at first as "Continental Morse," although as its use spread it also became known as "International Morse." At this point the original Morse Code started to be called American Morse, to differentiate between the two main standards. There was some resistance to adopting International Morse in the US. This resulted in international Morse operators in the