Boshiro's profile

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Sun, May 10, 2020 7:00 PM

ARRIS SB8200 Modem Provisioning

I went through Xfinity chat wanting to insure my modem was up to date. They pointed me to ARRIS support. Arris reviewed my modem settings and indicated the downstream channels were fine but there were problems with the upstream channels. I only have three out of four channels and the power levels were low. Power should be in the 45-51 range. Arris said this could cause drops and disconnections to get Xfinity to fix it. I passed this on in chat and Joseph said to call back next day to their "higher fix agency" to get it fixed. I called and after much effort by Alexandria she determined it was outside her ability to provision a non xfinity modem. My question is how do I get the upstream channels provisioned? 


Couple notes. Cable comes from the pole to the house. From that point, I have replaced the cable  to the modem (20'). There are no splitters.


Also, the modem as been rebooted by xfinity a few times and I have done the factory reset a number of times.


Upstream Bonded Channels
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 2 Locked SC-QAM Upstream 27600000 Hz 6400000 Hz 41.0 dBmV
2 3 Locked SC-QAM Upstream 21200000 Hz 6400000 Hz 41.0 dBmV
3 1 Locked SC-QAM Upstream 34000000 Hz 6400000 Hz 41.0 dBmV



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1 y ago

@Boshiro wrote: ... Power should be in the 45-51 range.

Arris began saying the upstream should be in the 45-51 dBmV range more than a year ago. I don't know why, because it's nonsense. Comcast's signal specs are the ones posted in the Connection Troubleshooting Tips Forum article, which says the Upstream Power Level at the modem should be between +35 dBmV and +50 dBmV. Also, +51 dBmV upstream is borderline too high.


The upstream power level is controlled automatically by Comcast's equipment and does not need to be above 45 dBmV. Many customers have service that works perfectly fine with upstream power levels below 45 dBmV. Some even operate with the upstream below 35 dBmV. That's because what's important is not the level at the modem, it's the level (and quality) of the modem's signal as received at Comcast. Comcast reps have no control over this, it's automatic and built into the system.


... she determined it was outside her ability to provision a non xfinity modem. ...

More nonsense. ALL modems and gateways, whether rental or customer owned, must be provisioned to work with Comcast's system. If your modem wasn't provisioned, it wouldn't work at all. And again, the upstream power level is controlled automatically. Phone and chat reps have no manual control.


Are you connecting via Wifi or Ethernet? If Wifi, try switching to an Ethernet cable connection if possible as a test. That would allow you to determine whether the problem is the Wifi signal or the link between your equipment and Comcast's network. Network connection problems that affect both Ethernet and Wifi devices are often due to poor coax connections, usually in or near your home.

If you want to troubleshoot this yourself, please see Connection Troubleshooting Tips. If you still need help, please also post the remainder of your modem's signal information, especially downstream power levels and SNR, and the error log.

If you can't find the problem or you'd rather have Comcast take care of it, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on If they can't fix the problem remotely (unlikely), insist they send a tech out to identify the cause and correct it.

If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit unless you have their Service Protection Plan (, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device, or anything outside your home, you shouldn't be charged.

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