An equipment that establishes, maintains, and terminates a connection, and performs the conversion necessary for communications. For example, in the case of an EIA 232-D connection, the modem is usually considered as DCE.

Data circuit-terminating equipment is required to attach data terminal equipment (DTE) to a network or serial line. Data circuit-terminating equipment (DCE) includes devices such as modems and ISDN terminal adapters.

In a communications link, equipment that is either part of the network, an access point to the network, a network node, or equipment at which a network circuit terminates. In the case of an RS-232-C connection, the modem is usually regarded as DCE while the user device is DTE, or data terminal equipment; in a ITU-T X.25 connection, the network access and packet-switching node is viewed as the DCE. Also known as data communications equipment.