An Experimental Automatic Communication System for Air Traffic Control

The "Experimental Automatic Ground/Air/Ground Communication System (AGACS)" under development for the Bureau of Research and Development, Federal Aviation Agency, will provide a two-way traffic control data link permitting automatic mechanized communication for essential routine flight information between the air and ground environments. The system selected is operable in both VHF and UHF aircraft communication bands and permits choice of FSK-carrier or FSK-AM modulation. Up to 500 aircraft may be interrogated and reply on a single channel in a time period of two minutes or less. Information is binary coded and transmitted by time-division multiplex techniques at a data rate of 750 bits per second.