Nighthawk CM1150V Drops Dial Tone With New Phone

[factman]

I originally posted this in another forum and somebody there suggested I post it in this forum. The problem rests with the personal phone line connected to the CM1150V -- which keeps losing the dial tone. Keep in mind that this problem has started only after getting new phones as described below. There has been nothing wrong until now. Comcast is set up for this voice modem. 

Our ancient RCA 4-line phones had been working okay with the CM1150V voice modem since I got the CM1150V in January 2021, but they really needed replacing after 20 years especially since I now have just two phone lines. Frustratingly, the 2-line system I found and really like, Panasonic's KX-TG9581 Corded/Cordless Phone with "link-to-cell" (a feature I have not activated) keeps losing the dial tone on the personal line which is connected to this Nighthawk CM1150V voice modem.

 My business line is connected to a separate Arris voice modem that Comcast supplied (and the new phone has worked flawlessly with this modem). The problem is with the Netgear CM1150V.

After a few hours and sometimes after a day or two, the dial tone just disappears from the personal line plugged into the CM1150V. To restore the dial tone, I've had to reset the modem via Comcast's site. The Panasonic phone is a DECT6.0 (Digital enhanced cordless Telecommunications 6.0) with Bluetooth. The base unit is connected directly to the modems. I ran into the same problem with a VTech DECT 6.0 system I tried before settling on the Panasonc system.

So I am wondering if the Netgear CM1150V is incompatible with DECT 6.0 phones even though Netgear's site asserts "Your cable telephony modem is compatible with wired phones and cordless DECT (Digital Enhanced Cordless Telecommunication) phones. Your cable telephony modem does not have DECT hardware installed. In order to use your DECT phone with your cable telephony modem, you must have a DECT base station." And indeed, it is my DECT base station that is connected via the phone lines to the Netgear CM1150V modem.

The cabling to our house is fine. Comcast has configured the modem for phone services. Is it possible that Comcast needs to reconfigure the modem now that I'm using a DECT 6.0 phone? 

I am hoping that somebody in this community may have some clue as to what could be causing the dial tone to simply disappear like this and how to cure the problem.

Thanks for whatever guidance can be provided. 

[factman · Accepted solution]

Solved, no thanks to any tech support from Netgear or Panasonic.

After a lot of experimentation, I stumbled upon deep in the new phone's settings, something called "Line Mode." I've since learned that modern DECT 6.0 phones have this buried deep in their internal phone system menu -- and both phone systems with which I had lost the dial tone were DECT 6.0 systems. The setting for the business phone line that worked was "B." The setting for the personal phone line that was losing the dial tone was set on "A." Long story short, I reset the Line Mode for the personal line to "B" and it has not dropped the dial tone even once in over a week.

Thanks so much for the time and thought you devoted to solving this problem.

[FURRYe38]

Be sure to have the ISP check the signal on the coax and phone lines up to the modem. 

Be sure the ISP configures the modem for phone services. 

Contact the Mfr of the new phones for help and support regarding there product. If prior phones worked and news ones don't, there maybe a compatibility issue. 

[FURRYe38]

Any progress on this? 

---

@factman wrote:

I originally posted this in another forum and somebody there suggested I post it in this forum. The problem rests with the personal phone line connected to the CM1150V -- which keeps losing the dial tone. Keep in mind that this problem has started only after getting new phones as described below. There has been nothing wrong until now. Comcast is set up for this voice modem. 

Our ancient RCA 4-line phones had been working okay with the CM1150V voice modem since I got the CM1150V in January 2021, but they really needed replacing after 20 years especially since I now have just two phone lines. Frustratingly, the 2-line system I found and really like, Panasonic's KX-TG9581 Corded/Cordless Phone with "link-to-cell" (a feature I have not activated) keeps losing the dial tone on the personal line which is connected to this Nighthawk CM1150V voice modem.

 My business line is connected to a separate Arris voice modem that Comcast supplied (and the new phone has worked flawlessly with this modem). The problem is with the Netgear CM1150V.

After a few hours and sometimes after a day or two, the dial tone just disappears from the personal line plugged into the CM1150V. To restore the dial tone, I've had to reset the modem via Comcast's site. The Panasonic phone is a DECT6.0 (Digital enhanced cordless Telecommunications 6.0) with Bluetooth. The base unit is connected directly to the modems. I ran into the same problem with a VTech DECT 6.0 system I tried before settling on the Panasonc system.

So I am wondering if the Netgear CM1150V is incompatible with DECT 6.0 phones even though Netgear's site asserts "Your cable telephony modem is compatible with wired phones and cordless DECT (Digital Enhanced Cordless Telecommunication) phones. Your cable telephony modem does not have DECT hardware installed. In order to use your DECT phone with your cable telephony modem, you must have a DECT base station." And indeed, it is my DECT base station that is connected via the phone lines to the Netgear CM1150V modem.

The cabling to our house is fine. Comcast has configured the modem for phone services. Is it possible that Comcast needs to reconfigure the modem now that I'm using a DECT 6.0 phone? 

I am hoping that somebody in this community may have some clue as to what could be causing the dial tone to simply disappear like this and how to cure the problem.

Thanks for whatever guidance can be provided. 

---

[factman · Accepted solution]

Solved, no thanks to any tech support from Netgear or Panasonic.

After a lot of experimentation, I stumbled upon deep in the new phone's settings, something called "Line Mode." I've since learned that modern DECT 6.0 phones have this buried deep in their internal phone system menu -- and both phone systems with which I had lost the dial tone were DECT 6.0 systems. The setting for the business phone line that worked was "B." The setting for the personal phone line that was losing the dial tone was set on "A." Long story short, I reset the Line Mode for the personal line to "B" and it has not dropped the dial tone even once in over a week.

Thanks so much for the time and thought you devoted to solving this problem.

[FURRYe38]

Glad you got it working. Enjoy.