I have a client that has a Cisco 3825 & 2 WIC-1DSU-T1 cards he bought. I cannot see the cards at all. From what I can find in the CISCO documentation, the 3825 uses the WIC-1DSU-T1-V2, however there is nothing that says the older cards (WIC-1DSU-T1) are not compatible.
Before I have him send...