No dial tone for ADT

[Rdry19521]

I recently switched from frontier to xfinity. Since the phone comes in on a coax it's is not hooked up to the home phone wiring, so my alarm does not have a dial tone. The alarm worked fine with frontier so there is nothing wrong with the phone jacks. Do I need an adapter to change from voip to pots so I can hook it to the home jack and get a dial tone for alarm? I tried hooking directly from the modem to the wall jack and that didn't work. 

[CCAndrew]

Have you checked for dial tone out of the modem with a phone?

[Rdry19521]

Yes it works there. 

[CCAndrew]

Is that the same phone jack frontier back fed to? When you backfeed to the phone jack do your other phone jacks work?

[Rdry19521]

Yes, the same jack. The other jacks don't work when I plug it in from the router. There are two places on the router for a phone line and I've tried both. 

[CCAndrew]

Then it boils to your home wiring if you get no dial tone but you do at the modem. Is frontier hooked up still in some way, there’s a short somewhere. What modem do you have?

[Rdry19521]

Cisco cgm4140com

[Rdry19521]

I found a place in my Xfinity settings to set my router up so I did that again and now I have a dial tone on my other jack, but not in the ADT box. 

[Rdry19521]

I cut the wires from frontier on the outside of the house. 

[CCAndrew]

Did you possibly cut something you weren’t supposed to? Depending on the age of ADT system, is it compatible with Comcast? Since it’s only affecting ADT, it might be their service call to handle

[Rdry19521]

I just cut the 4 small wires going in the house. The house was built in 02 so I'm thinking the alarm is that old. I've talked to Xfinity and ADT both and they thought it would be the other company's problem. But since I have a dial tone now I'll give ADT a call again. That's for the help.