Cisco - HWIC-4B-S/T= - 4-port ISDN BRI High-Speed WAN Interface Card new and refurbished buy online low prices
Cisco High-Speed WAN Interface Cards - Support - Cisco
Cisco 2921 Integrated Services Router - 1 x SFP (Mini-GBIC), 2 x CompactFlash (CF) Card, 4 x HWIC, 2 x Services Module, 3 x PVDM - 3 x 10/100/1000Base-T WAN - CISCO2921-SEC/K9