Here's my setup. I have Suddenlink cable, data, and phone. I live in a Smart home. I have connected my router's #1 port by ethernet cable to the input on my Ruckus whole house router, this giving me whole house WIFI through my ceiling hot spot. In all my rooms there are no RJ11 phone jacks, just RJ45 ethernet jacks. To get my cordless telephone system to work I had to place my phone base near the modem and connect it to the #1 phone jack on the modem. I have a second phone line on the #2 phone jack on the modem that I wanted to use for a fax line with my all in one printer. Is there a device that connect this second phone line to my network that will provide fax capabilities to my AIO via the ethernet connection on the printer?
No you can't connect an analog phone line into your network for sharing, but you can wire the phone to any of the jacks that use ethernet, just use less wires and maybe would need to change the plate on the wall. The basic wire for phone and ethernet is the same thing, a metal wire going to jack. Ethernet is just more shielded and uses more wires.