Introducing Cox Gigablast

What wire did you fish through the attic? It is fiber into the house into a ONT, and then ethernet is output from the ONT into the Netgear router they provide. There is no "modem" or coaxial used. I would suggest running ethernet through the attic, from where ever the ONT will be (usually on the opposite of where ever your house box is) to the computer center room. This way, either you can put the router in the computer room, or run ethernet from the router (next to ONT) to the computer room and install a switch or AP.

Here is a video with a break down of the install.