To provide the real flexibility to its customers Cisco offers a variety of networking solutions. The Cisco routers feature network module slots, each of them accepts different network module interface cards, supporting a variety of LAN and WAN technologies.This ISDN BRI U WAN Interface Card provides your Cisco 1600, 2600, 3600 series routers with one ISDN BRI port (U interface, internal NT-1, RJ-45 connector). Note that this card does not support hot swap; however, no hardware damage will occur if it is swapped while power is on.