router communication with DSL

Yesterday I attempted to hook up a router between my computer (well established stability therefore not the problem) and my DSL modem ( Cisco 675 provided by my ISP ). Now I've hooked up a couple routers before - both were the same - Linksys 4 port 10/100's. but I've never had this problem before - the computer would connect to the router with no problem, but the DSL Cisco wouldn't connect to the router. it's as though there wasn't even a cable between them. Thinking there was something wrong with the router I took it back and they tested it. I worked just fine in ALL aspects. Assuming a hardware incompatibility - I exchanged it for a Netgear router...same problem - no connection with the DSL.

Has anybody had this problem before? is there a way to fix it without calling my ISP and paying for a second connection?

<A HREF="http://thehub.eg.st" target="_new">The Hub</A>

What kind of cable are you using from the modem to the router?

<b><font color=blue>~ <A HREF="http://forums.btvillarin.com/index.php?act=ST&f=41&t=324&s=58e94ba84a16bedfebbf0f416d5bac48" target="_new">System Specs</A> ~<font color=blue></b>

I use the cable that came with the router ( ie NOT a twisted pair ). I have tried different cables. No link light comes on when I plug in the cables on either the DSL or the router. I know my router works because I watched the guy at the store prove to me that it works before I would buy it. link lights came on at the store using the same cable - but it won't connect at home. That tells me that it's something to do with my DSL.