Community Forum

Telephony connection.

Frequent Visitor

Telephony connection.

Greetings all,


My newly replaced XB6 Technicolor CGM4140COM modem has dropped all telephone connection. Any ideas? (Tried  connecting directly to phone thereby bypassing house wiring with no change.) Comcast unable to diagnose over the phone. This is my 2nd XB6 in two weeks. Could this one have an  isolated faulty internal telephone modem ? Regardless, advertised speed is barely half what they claim. Current speed with 5G connection and 250 Mbps plan = 

103.7 Mbps
10.8 Mbps
Do these new boxes need firmware &/or software upgrades?
That $398 Netgear Nighthawk X4S C7800 Wireless Router Modem - 2.4 GHz / 5 GHz - Gigabit Ethernet - 802.11b/a/g/n/ac is looking more attractive than ever.
Anyone else with these problems? Solutions?
Thanks all.
Silver Problem Solver

Re: Telephony connection.

The advertised speed is for an Ethernet connection.

I am not a Comcast employee; I am just a customer, volunteering my time to help other customers here in the Forums.
Diamond Problem Solver

Re: Telephony connection.

First. Test the speeds here with an ethernet connection. What is the upload speed ?


Re: Telephony connection.

Hi @ren1pa,

I've asked a Comcast employee to help you. You should expect a reply in this thread. 


While you wait for a reply see the troubleshooting guide

I am not a Comcast employee, just a moderator. Pls observe Wheaton's Law.
Official Employee

Re: Telephony connection.

Hello, I can assist you further from here. To protect the privacy of your account, can you provide your full name, street address including city, state, and zip code (and apartment number if one is associated), and the full account number or phone number associated with your services. To send a private message click on my name, then click private message me.

Frequent Visitor

Re: Telephony connection.

Yes, I’m embarrassed about not realizing how the speed tests were measured! I should have known better. Anyway, thanks to all those who replied.

Concerning the telephone issue, this was not corrected until the tech made a home visit and determined that the Comcast office had not activated the telephone portion of the overall activation.

All is well,

Thank you all.


XBS Speed with 3ft (6Ae) cord.

Speed Results

DOWNLOAD SPEED    270.3 Mbps

UPLOAD SPEED    11.8 Mbps

Latency   11 ms

Protocol   IPv6

Host   Foxboro, M

Official Employee

Re: Telephony connection.

Hey, there is no need to be embarrassed, I completely understand. And thank you for updating me on this issue. If you need any further help going forward please reach out to us, we are always here to assist. Thank you.