Fiber optics with the C7100v modem/router combo

> How do you (or can you) connect At&t fiber optics (ONT) to the Netgear
> C7100v (voice) router/modem?

   Because the C7100V has no WAN/Internet Ethernet port, it's generally
useless as a router in a non-cable-TV environment.

   A cable modem+router is not _absolutely_ useless without a cable ISP
connection.  See, for example:

      https://community.netgear.com/t5/x/x/m-p/1463500

But it _is_ useless as a _router_.