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Anyone have any experience using an old landline corded telephone with a Cox router for phone service?
Do you mean a normal corded phone? As long as it's capable of pulse tone, it should work fine. As far as what phones and devices work, it's the same as the old system. It wouldn't be a router exactly, but either a internet/phone modem (eMTA) or a internet/phone/wifi gateway. Either will have a normal phone jack (RJ11) on the back you can plug any phone into.
It’s a push button phone from the 1980s. I’m plugging it into the phone jack on the back of my Cox modem. Cox service chat is trying to tell me that using an old phone can damage the modem and I don’t believe them.
Nahh. No damage at all. I would suggest connecting it DIRECT into the modem though, instead of going through the phone wiring/outlets in your house. That's because older phones can sometimes require stronger signal (REIN) through the phone cord to make the phone ring. As long as it works though, and you do a test call, you are all set. My guess is the representive had it backwards and thought old phones CAUSED more REIN instead of REQUIRING more instead.
I have 3 cordless phones with a base on my Cox home phone system...but I also have an old "slimline" touchtone phone directly wired into the outlet on the wall and have no problems with it.
Yea, I never meant to insinuate older phones won't work when connected through a phone jack in the wall, just that if it didn't work (for complicated reasons) to try connecting it direct to the modem instead. Heck, even if you have a old rotary phone, you can call Cox and ask them to switch your modem to rotary mode, but then it just won't work with newer phones. So you can get just about anything to work, just "some" REALLY old phones might need some fiddling.