Abbreviation for digital data communication message protocol. A data link
control protocol developed by Digital Equipment Corporation. It is similar to
and HDLC but is character-oriented rather than bit-oriented. It allows a
variety of data link characteristics: full duplex or half duplex, asynchronous
or synchronous, switched or dedicated, point-to-point or multipoint, and serial
or parallel. Data transparency is achieved using a data-length field rather than
bit or byte stuffing techniques. Active NAKs are used for error control, in
addition to timeouts.