Special Features:

Operates half-or full-duplex over four-wire leased older type 3002 or nnewer service types 5, 6, 7, or 8 unconditioned voice-grade private lines, or international ccitt m1040 or equivalentlines; may be used on either point-to-point or multidrop circuits; operates in half-duplex mode over two-wire dial-up lines when the two-wire dial interface option in installed

Properties:

An item which modulates and demodulates one or more electrical signals. It connects data terminal equipment to a communication line or network such as telephone, radio or telegraph. It may include the multiplexing and demultiplexing circuits, circuit amplifiers and source(s) of carrier frequency. For items designed for light signals, see modem, fiber optic.