The Q-code is an international set of abbreviations that was created at the beginning of the last century to simplify radiotelegraph communication. Each code is composed by three letters always starting with Q. Each code can be a question if followed by a question mark or an answer (or statement) if not. To avoid confusion, no station call-sign begins with Q. Even if initially designed for telegraphy, it’s also used in voice communications.
Amateur radio international Q-code
Amateur radio operators use a subset of the full international Q-code and they use it extensively still today. In many countries, learning this code is necessary to obtain a Ham Radio license, the exact subset used may slightly vary from country to country. Sometimes Q-codes are used informally with a slightly different meaning.