The Digital Data Communications Message Protocol (DDCMP) module is a
    data link control procedure that ensures a reliable data communication
    path between communication devices connected by data links. DDCMP has
    been designed to operate over full- and half-duplex synchronous
    and asynchronous channels in both point-to-point and multipoint
    modes. It can be used in a variety of applications such as
    distributed computer networking, host/front end processing,
    remote terminal concentration, and remote job entry-exit system
    operation.