I just bought a new Cisco DPC3000 cable modem. When I plug it into my pc directly it works fine. When I plug my D-Link router (DGL-4300) into it, there's never any activity light on the modem. Needless to say, it the router can't get an IP and connect to the internet because some low-level hardware communication just isn't happening. I can connect my router to my old Motorola Surfboard SB5100 and I get an activity light on that without a problem, so the ports are fine and the router works. Is there some sort of incompatibility with 10/100 wan routers? What could be the problem?