If you have phone service through Comcast, you'll need a phone cord not Ethernet) from the modem's phone port to the phone jack. If those phone jacks are connected in your home's wiring, you'll get a dial tone. If there's no dial tone, the phone wires aren't connected. This has nothing to do with your router. Also out of the Netgear, there is connection to Edgemarc router, which then goes to an Arris modem. So the local lan appears to be shared between PC's and the Comcast Polycom phones, but somehow through the same unmanaged switch, the phone traffic goes out the Edgemarc then Arris and the PC traffic goes out the Comcast Business modem.
The Xfinity router wiring diagram is divided into two separate diagrams. The first diagram is for the power supply and the second diagram is for the phone line. In the power supply diagram, the cable from the main power source is connected to the power connector of the router. The other end of the cable is connected to the power supply unit.. In the context of a Comcast phone connection diagram, the telephone is connected to the router via a phone cable, and it uses the internet connection provided by Comcast to make and receive calls. Cables: Various cables are used in a Comcast phone connection diagram to connect the different components together.