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Upstream Channels Not Bonding - Upload Highly Unstable, NEED Line Technician
Hi,
I’ve already worked with Xfinity Support through the app twice, but both times the troubleshooting was unhelpful. I had to do an extreme amount of “homework” on my own to pinpoint what’s actually wrong, and it’s clearly not something a reset or in-home tech can solve.
My modem (Netgear CM1200) shows:
Only 4 upstream channels locked (should be 4–8).
Both upstream OFDMA channels not locking at all.
Upstream transmit power ~40–43 dBmV.
Downstream looks fine, SNR ~41 dB.
I’ve ruled out equipment by testing:
Multiple devices (PC, phone, streaming).
Direct-to-modem (bypassing router).
Different Ethernet cables.
This is not my equipment - it’s an upstream return path issue on the line. Upload drops constantly daily, causing Discord/gaming disconnects and video call freezes.
At this point, I need this escalated to a line technician/truck roll (outside line, not in-home).
Can someone from Xfinity Support please review my signals and schedule the appropriate maintenance?
Thank you.
XfinityDemitrius
Official Employee
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2.2K Messages
10 days ago
Hey @user_bgqdhl, Thank you for visiting our official Xfinity Forums Community support page. We appreciate you going through all the steps and providing such detailed information. As the device is not supported for our Next Generation Internet enhancements, the OFDMA channels may not bond. As such, not all upstream channels may bond as well.
Reviewing the specifications provided, the upstream transmit power and downstream Signal-to-Noise ratio. Upstream transmit power should be between 25- 54 dBmV and the downstream SNR should not go below 31 dB. 4 channels locked should be more than plenty to provide the upload speeds.
Have you had the change to check all coax connections from the service distribution enclosure, splitters, amplifiers, and equipment? Is there any unneeded cable splitters, amplifiers, and extra long coax that may not be needed?
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