Logging on to SMCD3GN cable modem?

  I'm having no luck getting through to the web admin interface for the new cable modem Time-Warner installed here.
  I need to get in there to adjust the config so I can get to my desktop remotely using a dynamic DNS address. It worked fine with the old modem. It's a pretty simple matter to program the routing table so things work properly. But you have to be able to get through to manage the configuration, and I can't get to the login screen.
  The instructions in the manual are pretty clear.
  They say to connect to http://192.168.0.1/ and enter cusadmin and password as the username and password. But when I go to that address, it says it's connecting, then sits there for a while and times out.
  Here's a photo of the plate on the back of the modem with the MAC addresses blocked.
  Any ideas?