The Cisco 1-Port 4-Wire 56-/64-kbps CSU/DSU WAN Interface Card (HWIC-1DSU-56K4) performs the channel service unit/data service unit (CSU/DSU) functions for both digital data service (DDS) (dedicated) and 4-wire switched 56-kbps (56K) data networks. In addition, it provides an all-rate synchronous interface to any dedicated DDS point-to-point or multipoint network compatible with AT&T Publication 62310. The new card also supports 4-wire switched 56K data services such as AT&T's Accunet 56 or Sprint's VPN-56 plus many switched data services offered by local exchange carriers.