Well, if you really want to just support the one platform (specific windows version), then I suppose the protocol to use would be PPP.

If you can get a windows PPP client pointed at the USB, then on the Empeg side it oughta be pretty easy to get PPP running off the USB as well.

But more complete solution would be ethernet emulation for some popular USB-ethernet device, so that we get multi platform support out of this.

Cheers