AFTN (Aeronautical Fixed Telecommunication Network) is connected between international airports, Air traffic control facilities and international airline companies. It ensures the telecommunications of international air navigation, and exchanges vital information for aircraft operations such as distress messages, urgency messages, flight safety messages, meteorological messages, flight regularity messages and aeronautical administrative messages.

ATFN teletype addresses are 8 characters long, whereas SITA teletype addresses are 7 characters long.