[Modem Request] Technicolor XB8

[SideTrackedResearch]

Modem Model

Technicolor XB8

Firmware Version

CGM4981COM_8.2p7s1_PROD_sey

Internet Service Provider (ISP)

Comcast/Xfinity

What Features Are Working?

• Downstream channel data (frequency, power, SNR, errors)
• Upstream channel data (frequency, power)
• System information (firmware version, uptime)
• Modem restart functionality
• All channel counts are correct

Channel Counts

33 down. Showing 5 up with 'unknown'

How Was Parser Selected?

Manually selected from dropdown

Any Issues or Limitations?

I used the XB7 Parser.
The five up channels are reading Unknown.
The down channels are changing as I write this. Some will go to 'unknown' and back to a reading.
Restart button is grayed out.

Diagnostics File

• I have attached a diagnostics file to this issue

Additional Context

config_entry-cable_modem_monitor-01KD2EKA63BNZJ689PZABC2ZT7.json

home-assistant_2025-12-22T07-53-10.777Z.log

[kwschulz]

Hi there,

Thanks for reporting this. I've updated the issue title since this is actually a new modem request - the XB8 isn't officially supported yet, so there's no asterisk to show.

As you discovered on your own, the XB7 parser is authenticating successfully, which is the hardest part. The upstream parsing is failing, likely because the XB8 has a slightly different HTML structure.

To build the fixtures, tests, and parser for the XB8, I need to see the raw HTML:

1. Go to Settings → Devices & Services → Cable Modem Monitor
2. Press the "Capture HTML" button
3. Wait for the notification confirming capture is complete
4. Download Diagnostics within 5 minutes
5. Attach the new diagnostics file here

See Integration Capture instructions for details.

[SideTrackedResearch]

Here you go. I thought I would try it on the XB8 and got something. I did notice Xfinity is moving things to their app for access to the modem and limiting some settings.

config_entry-cable_modem_monitor-01KD2EKA63BNZJ689PZABC2ZT7(1).json

[kwschulz]

Thanks for the capture - this is helpful.

The XB7 parser is mostly working (33 downstream, 5 upstream detected), but there are a couple of parsing issues causing "Unknown" values. To fix properly, I need to see the raw HTML structure, which the current capture didn't fully grab.

I'm working on auth improvements for v3.12.0. Once that's released, can you do a fresh "Capture HTML" from the integration? That should grab everything I need in one click - no HAR/script setup required.

I'll ping you when it's ready.