Morse code become commonly available until around 1920. Until 2003, the International Telecommunication Union mandated Morse code proficiency as part of the amateur radio licensing procedure worldwide. However, the World Radiocommunication Conference of 2003 made the Morse code requirement for amateur radio licensing optional. Many countries subsequently removed the Morse requirement from their licence requirements. Until 1991, a demonstration of the ability to send and receive Morse code at a minimum of five words per minute (wpm) was required to receive an amateur radio license for use in the United States from the Federal Communications Commission. Demonstration of this ability was still
Morse code in Morse code format, would normally be written something like this, where – represents dahs and · represents dits: Next is the exact conventional timing for this phrase, with = representing "signal on", and . representing "signal off", each for the time length of exactly one dit: Morse code is often spoken or written with "dah" for dashes, "dit" for dots located at the end of a character, and "di" for dots located at the beginning or internally within the character. Thus, the following Morse code sequence: is orally: "Dah-dah dah-dah-dah di-dah-dit di-di-dit dit, Dah-di-dah-dit dah-dah-dah dah-di-dit dit". There is