ATU-C (ADSL Transmission Unit-Centralized) An asymmetrical digital subscriber line (ADSL) modem located at the telco central office (CO) or other headend location. The ATU-C is the line side interface of a digital subscriber line access multiplexer (DSLAM). A matching modem, known as an ADSL transmission unit-remote (ATU-R) is located on the customer premises. See also ADSL, ATU-R, CO, DSLAM, headend, and modem. |