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user_u1aaq0
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Conversation Starter

Contributor

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43 Messages

Wednesday, June 25th, 2025 6:49 PM

Missing 16 downstream channels?????

Isn't the XB8 supposed to have and use 32 downstream channels?? I've got 29, 2 through 8 and 37. Nothing else. What gives?

Question

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Updated 

15 days ago

33

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XfinityPeterH

Official Employee

 • 

2.1K Messages

17 days ago

Yes, the XB8 is designed to support up to 32 downstream channels 1. If you're only seeing 29 channels, there could be a few reasons for this discrepancy:

Firmware Issues: Sometimes, firmware updates can cause changes in the channel bonding configuration. If your XB8 recently updated its firmware, this might be the cause.

Signal Quality: Poor signal quality or interference can prevent some channels from locking properly. Check the signal levels and ensure they are within the recommended range (Downstream: -15dBmV to +15dBmV, Upstream: +45dBmV to +51dBmV).

Provisioning Problems: There might be an issue with how your modem is provisioned by Xfinity. Contacting Xfinity support can help verify if your modem is correctly provisioned for 32 channels.

Hardware Issues: Although less common, there could be a hardware issue with your modem.

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0

user_u1aaq0

Contributor

 • 

43 Messages

17 days ago

@XfinityPeterH Just got it this morning. Checked the status and found that the gateway doesn't have all 32 channels locked in. Just restarted it and it's showing 3 downstream channels, instead of the 8 that showed initially. Currently, none of the upstream channels are shown.

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user_u1aaq0

Contributor

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43 Messages

17 days ago

Downstream
Channel Bonding Value
Channel ID
42
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
37
Lock Status
Locked
Locked
Frequency
405 MHz
690000000
SNR
42.3 dB
40.5 dB
Power Level
8.4 dBmV
5.2 dBmV
Modulation
256 QAM
OFDM
*Channel ID 42 is the Primary channel
Upstream
Channel Bonding Value
Channel ID
1
0
0
0
0
Lock Status
Locked
Frequency
35 MHz
Symbol Rate
5120
Power Level
37.8 dBmV
Modulation
QAM
Channel Type
ATDMA
CM Error Codewords
Channel ID
42
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Unerrored Codewords
0
28013750
15416573
15423015
15452961
0
15467778
15482514
15497357
15509891
15526353
15537803
15559799
15568781
15578686
15589779
15602382
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Correctable Codewords
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Uncorrectable Codewords
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

7

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XfinityBrianH

Official Employee

 • 

1.5K Messages

Thanks for providing that information. I am trying to check the device from my end, but I am having trouble. Is the device currently plugged in and powered on?

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

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17 days ago

0

user_u1aaq0

Contributor

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43 Messages

Yes, it is. Internet is working, too. Missing info is really mystifying.

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17 days ago

0

XfinityAlfonso

Official Employee

 • 

1.8K Messages

So we're showing that the new modem isn't fully activated yet, which is likely why you're seeing what you see. We'll send signals out and fully complete this order, then you should be good to go. You'll lose connectivity for a few minutes as this happens. Can we do that now for you? 

 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

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17 days ago

0

user_u1aaq0

Contributor

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43 Messages

Yes, please, go ahead.

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17 days ago

0

user_u1aaq0

Contributor

 • 

43 Messages

No love. 

Device Information

HW Version: 2.5
Vendor: Technicolor
BOOT Version: S1TC-3.81.22.7
Model: CGM4981COM
Product Type: XB8
Flash Part: 4096 MB
Download Version: Prod_23.2_231009 & Prod_23.2_231009
Core Version: 1.0
Downstream
Channel Bonding Value
Channel ID
5
2
3
4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
37
Lock Status
Locked
Locked
Locked
Locked
Locked
Frequency
507 MHz
489 MHz
495 MHz
501 MHz
690000000
SNR
41.9 dB
42.0 dB
41.9 dB
41.9 dB
40.5 dB
Power Level
6.9 dBmV
7.3 dBmV
7.2 dBmV
7.0 dBmV
5.3 dBmV
Modulation
256 QAM
256 QAM
256 QAM
256 QAM
OFDM
*Channel ID 5 is the Primary channel
Upstream
Channel Bonding Value
Channel ID
1
2
3
0
0
Lock Status
Locked
Locked
Locked
Frequency
35 MHz
29 MHz
22 MHz
Symbol Rate
5120
5120
5120
Power Level
37.8 dBmV
38.0 dBmV
37.5 dBmV
Modulation
QAM
QAM
QAM
Channel Type
ATDMA
ATDMA
ATDMA
CM Error Codewords
Channel ID
5
2
3
4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Unerrored Codewords
0
5339568
5349925
5348429
5354554
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Correctable Codewords
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Uncorrectable Codewords
0
0
0
0
0

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17 days ago

0

EG

Expert

 • 

111.6K Messages

15 days ago

@XfinityShawn @user_u1aaq0 

Be advised that sending an unrequested direct message to the support team is a violation of their forum guidelines. It may get ignored.


Please see this post about direct messaging the support team;


https://forums.xfinity.com/conversations/getting-started/direct-message/6445fb0eb9339b2013e8ff9c?commentId=6446bf50b9339b2013e93478  

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