A WAN interface card, or WIC, is a specialized network interface card (NIC) that allows devices to connect to a wide area network. (A NIC provides the interface between a device and a local area network.) A WIC has a built-in Channel Service Unit/Data Service Unit (CSU/DSU) interface that allows the card to communicate with a router that is connected to a WAN. The term is especially used in conjunction with hardware manufactured by Cisco Systems.
The typical WIC is a standard-size circuit card that fits into an expansion slot in the router. WICs are available for plain old telephone service (POTS), wireless networks, and proprietary wired networks. WICs are manufactured for use with all common network protocols. Data speeds range from 56 kbps for dial-up connections to the highest speeds supported by WANs. Modes include half-duplex, full-duplex, synchronous, and bisynchronous.