scope:

This specification states the conditions and requirements for furnishing and installing the electronic and associated equipment necessary for voice-data multiplex (VDM) terminals. The VDM terminals will be connected to various radar microwave links (RML's) to transmit voice and data information between various locations. The VDM terminals will operate over en route microwave link systems between Air Route Traffic Control Centers (ARTCC'S) and long range radar (LRR) sites, between ARTCC's and remote air/ground (RCAG) terminals at an en route microwave repeater station, and over airport surveillance radar microwave systems between the control tower and the remote radar location. The voice circuits may be various "hot" lines between controller personnel, administrative lines, and air/ground voice lines. The data circuits may handle any data speed, from low-speed voice frequency telegraph systems to high-speed 50 KBS systems. This shall be handled over varying channel bandwidths from standard 4 kHz channels to 48 kHz wideband circuits. Of paramount importance in the design of the VDM terminals is reliability, performance, and flexibility.