Comcast triple play. Need help with phone line/modem

To get Comcasts phone service you either need to rent the modem from them that has the phone capabilities, or rent a box for the phone service which costs the same amount as the modem rental alone.

SoccerFan: I have Comcast Triple play also. Here is my "wiring". (It may help if you sketch it out and then sketch out what you have in mind.)

Coax Wall outlet (where Comcast cable comes into the house) ------> Comcast provided Arris Cable Modem via coax Cable.

Arris Cable Modem Tel 1/2 Port --------> AT&T Telephone wired base station via RJ-11 telephone wire with plug in connectors each end.

Arris Cable Modem WAN Port -------> Linksys WRT1900AC Router Internet port (yellow) via RJ-45 Ethernet Cat5 Ethernet cable with connector on each end.

Notes:

I rent the cable modem versus buying my own because when Comcast service/support is needed they cannot blame the non-Comcast device.

The AT&T telephone wired base station (which I do own) provides support to four "cordless" telephones throughout the house. No other phones are connected to the existing telephone wall jacks. (In fact I removed some of the old wall jacks.) You may need to buy additional cordless telephone stations - just remember an electrical outlet will be needed for each of them.

The Linksys WRT1900AC Router provides networking and internet access to both wired and wireless desktops, an iPad, NAS, printer, and various cell phones from time to time.

Comcast does provide different cable modems. However the connectivity should be very much the same once you have identified the correct ports per thier icons or labling. Not sure if you get a choice. My ARRIS device supports the DOCSIS 3.0 standards. If you purchase your own devices make sure that: 1) Comcast supports them and 2) the devices are capable of the higher standards.

Did Comcast install the existing modem for you? If so I believe that your old land line connection was probably disconnected at the entry point to the house. They are now just using the telephone wall jack inside to feed back through the internal telephone wiring to service your existing telephones. I.e, the "current Comcast Wireless modem to the phone jack in the wall".

I try to avoid splitters whenever I can as the signal loss can degrade service. Also if you have both the wireless cable modem and a VOIP modem then power will be needed for each requiring an additional outlet and more wires.

I cannot say per se that separate modems would be better. By using just the ARRIS device I have a single point of failure. But at least Comcast cannot blame a third party device or devices as you envision. And I am fortunate enough to live close to a Comcast Center where I can exchange failed devices fairly easily.

Feel free to ask any other questions you may have. I am not afraid to be wrong or be otherwise "enlightened". Take care.