scope:

This specification establishes the performance, design, test, manufacture and acceptance requirements for modems, multiplexers, digital data service equipment and monitoring and support equipment to be used for the Data Multiplexing Network (DMN) subsystem in the National Airspace System (NAS). All modems/multiplexers, statistical multiplexers, ANMS equipment, HSTDMs, CSU/DSUs, LDMs, and the following ancillary equipment: interface adapters, port sharing devices, modem sharing devices, tail circuit synchronizers, "hot" standby switches, modem substitution switches, and patch panels shall be commercial off-the-shelf equipment. Production units shall be commercially available and be installed and fully operational in a system prior to operational capability demonstration. The clock box and the digital A/B switch need not be commercial off-the-shelf equipment.