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
Morse code abbreviations head, instead of writing text on paper or into a computer file, the receiving operator copying mentally will interpret the prosign for either a mental pause, or to jot down for later reference a short word or phrase from the information being sent. "Rag chewer" is a name applied to amateur radio Morse code operators who engage in informal Morse code conversations (known as "chewing the rag") while discussing subjects such as: the weather, their location, signal quality, and their equipment. Meaningful rag chewing between fluent Morse code operators having different native languages is possible because of a common language