WAN Interface Card
A WAN interface card is a specialised network interface card (NIC) that allows a network device such as a router to connect and transmit data over a Wide Area Network. A WIC has a built-in channel service data unit (CSU/DSU) interface to connect to a digital circuit and provide error correction and line monitoring.
A WIC is usually inserted into an expansion slot in a network router.
There are also CISCO HWIC's (High-Speed WAN Interface Cards) for data transmissions and CISCO VWIC's (Voice WAN Interface Cards) for both voice and data transmissions.