Gotta question. I've just started to try to gain a little knowledge about Cisco routers. So, I bought this very good unit called the 1604R. It has 1 WAN slot and the option to install a second WAN through a WAN interface card. The unit I have has a ISDN WIC. Now here is my question. Did I just buy an expensive router that can only be hooked up to an ISDN line? Cause I sure don't have and don't want a ISDN!! I have cable modem access and will be obtaining a T1 partial soon...but my problem is I don't know if I will be able to use them on this router or not. I know that I can but a different WIC for the T1, but I really can't afford that. So I wonder if that 1 WAN port that is built into the router itself (not the ISDN WIC) would work for this. P.S. I also have an external DSU/CSU but is not Cisco. Could I maybe use this as an option?