Cisco T1/Fractional CSU/DSU WAN Interface Card WIC-1DSU-T1 800-03279-03D0. The card includes an integrated data service unit/chanel service unit DSU/SCU and supports T1 and fractional T1 service.
Cisco Part Number: 800-03279-03D0
Cisco Model Number: WIC-1DSU-T1
Compatible Models: 1600 1700 2600 3600 Series