Hello,I am experiencing problems with my CM1200 repeatedly disconnecting and reconnecting multiple times unpredictably. I have proceeded with all the usual steps of disconnect and power off, wait ~ 1min, reconnect and power on, etc but still see the issue. Doing some digging it sounds like it might be an power level issue causing the modem to reset? I'm not sure and looking at connection I think things are within spec. I'm attaching screen grabs of my connection information since the table seems to be too large for formatting here. My ISP is Spectrum and I've scheduled an appointment for them to come take a look at my connection but I wanted to check here to see if there was anything I might be missing. Thanks!

The site is apparently not accepting any of my images, trying to repost them. They're in both JPG and PNG formats.

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.Be sure there are no coax cable line splitters in the between the modem and ISP service box. Be sure your using good quality RG6 coax cable up to the modem.

Thanks! I'll have them check those things, I don't think there are any splitters in the line. Do you have a recommendation for a good RG6 cable to use?

The ISP should have good RG6 Coax to use...

Had a second follow up visit on the issue and the Spectrum techs said everything looked fine from their end and saw no router failures, even when there were drops this morning before they got here. I can't determine what's going wrong or where. Here are the event logs if anyone can help me understand what I'm seeing. Tech took a look and said "I can't do anything with your personal equipment". Wed Mar 24 10:13:44 2021Critical (3)Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=08:36:c9:40:c3:d0;CMTS-MAC=00:17:10:86:bd:cb;CM-QOS=1.1;CM-VER=3.1;Wed Mar 24 10:13:44 2021Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=08:36:c9:40:c3:d0;CMTS-MAC=00:17:10:86:bd:cb;CM-QOS=1.1;CM-VER=3.1;Wed Mar 24 10:13:43 2021Warning (5)Dynamic Range Window violationWed Mar 24 10:13:43 2021Warning (5)RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=08:36:c9:40:c3:d0;CMTS-MAC=00:17:10:86:bd:cb;CM-QOS=1.1;CM-VER=3.1;Wed Mar 24 10:13:43 2021Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=08:36:c9:40:c3:d0;CMTS-MAC=00:17:10:86:bd:cb;CM-QOS=1.1;CM-VER=3.1;Wed Mar 24 10:13:37 2021Warning (5)Dynamic Range Window violationWed Mar 24 10:13:37 2021Warning (5)RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=08:36:c9:40:c3:d0;CMTS-MAC=00:17:10:86:bd:cb;CM-QOS=1.1;CM-VER=3.1;Wed Mar 24 10:13:37 2021Warning (5)Dynamic Range Window violationWed Mar 24 10:13:37 2021Warning (5)RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=08:36:c9:40:c3:d0;CMTS-MAC=00:17:10:86:bd:cb;CM-QOS=1.1;CM-VER=3.1;Wed Mar 24 10:13:37 2021Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=08:36:c9:40:c3:d0;CMTS-MAC=00:17:10:86:bd:cb;CM-QOS=1.1;CM-VER=3.1;Wed Mar 24 10:13:33 2021Warning (5)Dynamic Range Window violationWed Mar 24 10:13:33 2021Warning (5)RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=08:36:c9:40:c3:d0;CMTS-MAC=00:17:10:86:bd:cb;CM-QOS=1.1;CM-VER=3.1;Wed Mar 24 10:13:33 2021Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=08:36:c9:40:c3:d0;CMTS-MAC=00:17:10:86:bd:cb;CM-QOS=1.1;CM-VER=3.1;Wed Mar 24 10:13:27 2021Warning (5)Dynamic Range Window violationWed Mar 24 10:13:27 2021Warning (5)RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=08:36:c9:40:c3:d0;CMTS-MAC=00:17:10:86:bd:cb;CM-QOS=1.1;CM-VER=3.1;

CM1200 Repeated Disconnects | NETGEAR Communities

11 Replies

Telcontarr
Aspirant
Feb 26, 2021
The site is apparently not accepting any of my images, trying to repost them. They're in both JPG and PNG formats.
FURRYe38
Guru - Experienced User
Feb 26, 2021
Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box.
Be sure your using good quality RG6 coax cable up to the modem.
- Telcontarr
  Aspirant
  Feb 26, 2021
  Thanks! I'll have them check those things, I don't think there are any splitters in the line.
  
  Do you have a recommendation for a good RG6 cable to use?
  - FURRYe38
    Guru - Experienced User
    Feb 26, 2021
    The ISP should have good RG6 Coax to use...

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CM1200 Repeated Disconnects