Cisco WIC-1DSU-T1-V2 1-Port T1 CSU/DSU Card 800-22193-01 A0. The Cisco Systems T1 data service unit/channel service unit (DSU/CSU) WAN interface card is an integrated, fully managed DSU/CSU for T1 or fractional T1 service.

Cisco Part Number: 800-22193-01 A0
Cisco Model Number: WIC-1DSU-T1-V2
Compatible Part Numbers: 73-8346-03 A0
Compatible Models: Cisco 1600 1720 2600 3600 3700 Series