The WAN-interface-card (WIC) option offers a single ISDN BRI port (with optional NT1). The WIC inserts into a mixed-media network module or into the Cisco 1700, 2600, or 3700 chassis WIC slots. The ability to add BRI connectivity via a WIC enables administrators to maximize valuable slot space while providing additional connectivity options on the same module (for Cisco 3600 and 3700 series), such as Fast Ethernet.