This is the hardware at the CO (Central Office) that terminates an ADSL connection.

DSL ransceiver nit at the entral Office end.

ADSL Terminal Unit Central Office. Terminal nearer the central office or remote network node.

ADSL Termination Unit - Central Office The device at the end of an ADSL line that stands between the line and the first item of equipment in the telephone switch. It may be integrated within an access node.

ATU - Central Office. An ATU at the carrier's central office in support of DSL-based services.