Other Public Mobile Radio Systems 4.1 Airline Telephone Network for Public Air–Ground Communication In 1993 ETSI RES 5 submitted a standard for the Terrestrial Flight Telephone System (TFTS), specifying the radio interface and the interfaces to public telecommunications networks. At the same time the European Airlines Electronic Committee (EAEC) specified the airline equipment and interfaces to cabin facilities. Commercial operations began in 1994. In July 1994, after inviting international tende