The WIC-1T has a DB60 connector on it.
The WIC-2T has a smart serial connector on it.
The WIC-1DSU-T1 has a RH-45 style connector on it.
You can have the WIC-1t and WIC-2T work together with a special back to back cable. It just has to be db60 to smart serial. Obviously you can have wic-2t to wic-2t with a smart serial to smart serial cable.
WIC-1DSU-T1 cards need a special cable that can only be used with each other. Watch out as there is a v1 and a v2 of this modules and they each do not work in all models. Rougly the v1 is up to a 2600XM. The V2 is for ISR routers like a 1841, 2801, etc.