Custom Cable Router

Nothing that I know of will accept a coaxial cable directly into your computer for internet. You need a router for internet anyways, so why not use ethernet?

you can get a pci card based docsis cable modem... but you don't want one, as most ground loop issues arise from the cable network... this is why your standard external cable modems aren't grounded and don't come with a shielded patch cable, you want that isolation.

I'm pretty sure that any Zoom PCI cable modems you find will be ancient Docsis 1.0. The Zoom 5011 is almost a decade old now... Chances are your cable provider is Docsis 2.0...

Ethernet is a wonderful standard, and honestly, you don't want a direct internet connection to anything but a hardware firewall/router.

why?

I have a cable modem downstairs and a Netgear router that has both ethernet AND coaxial inputs from the modem. Then I plug directly into the router. Your saying I don't need the coaxial were I to build a custom router?

Can you build a modem?

Why not? I would assume a custom modem would be better than the one Comcast gives you.

A Linksys or Motorolla Modem is ~ $60, probably better than anything you could build and cheaper, and the fact that I doubt any cable company would activate it.