Q code

The Q-code is a standardised collection of three-letter codes that each start with the letter "Q". It is an operating signal initially developed for commercial radiotelegraph communication (used e. g. by the Maritime Mobile Service or Amateur Radio Service), later also for TeleTYpe (TTY. e. g. for AFTN, the Aeronautical Fixed Telecommunications Network) and RadioTeleTYpe (RTTY e.g. used by the Maritime Mobile Service or Amateur Radio Service) and in voice communications (e.g. Aeronautical mobile service). Most Q-codes defined in 1947 are still in use today, date back to the International Telecommunication Convention in Atlantic City, 1947 and are standardized in the ITU International Radio Regulations from 1947 (ITU-RR).