(ACU) The device attached to the sending DTE that facilitates dialing of a receiving DTE. It automatically performs the dialing function eliminating the need to manually dial the receiving DTE.

A dialing device supplied by the communication common carriers that permits a business machine to dial calls automatically over the communication networks. See: common carrier.

A unit, which may or may not be integrated within a modem, that automatically dials calls based on digits supplied by the attached business machine.