I purchased the CM1200 modem back in March of this year and haven't had an issue with until the past month and a half. I'm having an issue where my internet will randomly disconnect on both Wired and Wireless at the same time. These disconnects can range from a couple seconds to a couple minutes. I called our ISP (Comcast) asking if they could find anything wrong and they told me that they were having no issues. I replaced our router, thinking that was the issue at first since the internet symbol on the modem stays on even during these moments of disconnect but the routers didn't. But the new router (TP-Link Archer C5400X) hasn't fixed it. The modem is on the latest firmware version (V1.02.02). I've tried different ethernet cables on both the router and modem. On my router, I've tried changing channels, cloning my computers MAC address, setting up some IP configuration. On the modem, I enabled ethernet port aggregation. Nothing has worked so far. I'm thinking it's either a coaxial cable issue (but wouldn't my ISP see that?), or simply the modem itself. Thanks for any help you can provide!

You have t3 errors and power fluctuation errors. The snip just shows in the time the page was loaded but from looking at your log, the power must be spiking/dropping. If you didn't check your line and remove amplifiers, splitters, attenuators, do it now. If you already have, then I'd have your isp check your line.

log into the modem and get a screen snip of the cable connection page and the logs and post them back here. Also, if you have any splitters, attenuators, or amplifiers in line, remove them and direct connect the modem.

I don't have any extra stuff like that added on. Looks like another call to my ISP! Hopefully that gets it resolved. Thanks for the advice!

I just got confirmation of a modem being sent to me. I'm going to wait for that to see if it resolves the issue. My ISP just replaced the lines anyways and said they should be good now.

Update: The modem replacement came in Wednesday night and hadn't fixed the problem at the time. But the event log wasn't showing any errors like before and the db levels were fine. Now, we had just replaced the router as well thinking that was the original problem, but it is a TP-Link router. Fortunately, I purchased a NETGEAR router cause the other router replacement was taking a while to be delivered. So I hooked that one up yesterday afternoon and everything since then has been working fine. Now I'm wondering why that is? The TP-Link router was a brand new replacement. Is it just not as "compatible" with the modem since it's not the same manufacturer? Also, I'm thinking that this whole entire thing was just multiple things that needed to be fixed. With my lines being really old and replaced (fixing the 6db error but still having the T3 timeout error), my modem being replaced and not showing anymore errors (but still randomly disconnecting), then using a router from the same manufacturer. But once again everything seems to be running great. Thanks for assistance all. I'm a lot more knowledgeable about this than I was before.

Random Internet Disconnection on Both Wi-fi and Wired (CM1200 Modem)

18 Replies

plemans
Guru - Experienced User
Jun 19, 2020
log into the modem and get a screen snip of the cable connection page and the logs and post them back here.
Also, if you have any splitters, attenuators, or amplifiers in line, remove them and direct connect the modem.
- KiwiBoxer
  Guide
  Jun 19, 2020
  plemans
  I'm not sure how to attach multiple things so I hope an Imgur link of the screenshots is ok: CM1200 Screenshots
  Here is at least the event log if you're not ok with that.
  Thanks!
  
  Time Priority Description
  Fri Jun 19 10:00:22 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 10:00:22 2020 Warning (5) RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 10:00:22 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 10:00:22 2020 Warning (5) RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 10:00:22 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 10:00:22 2020 Warning (5) RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 10:00:22 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 10:00:22 2020 Warning (5) RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:54:56 2020 Notice (6) CM-STATUS message sent. Event Type Code: 24; Chan ID: 25; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0 1 2 3.;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:54:30 2020 Notice (6) CM-STATUS message sent. Event Type Code: 16; Chan ID: 25; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:36:52 2020 Notice (6) CM-STATUS message sent. Event Type Code: 8; Chan ID: 79 80; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:36:26 2020 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:36:26 2020 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:36:26 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:35:39 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:35:39 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:35:38 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:35:38 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:35:37 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:35:37 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:35:37 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:35:37 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:35:37 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:34:54 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:34:54 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:34:54 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:34:54 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:34:54 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:34:54 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:34:54 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:34:54 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:34:54 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:34:54 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:34:36 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:34:36 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:34:36 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:34:36 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:34:36 2020 Warning (5) Dynamic Range Window violation
  Fri Jun 19 09:34:36 2020 Warning (5) RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b3:1f:d0;CMTS-MAC=00:01:5c:79:10:69;CM-QOS=1.1;CM-VER=3.1;
  Fri Jun 19 09:34:35 2020 Warning (5) Dynamic Range Window violation
  - plemans
    Guru - Experienced User
    Jun 19, 2020
    You have t3 errors and power fluctuation errors. The snip just shows in the time the page was loaded but from looking at your log, the power must be spiking/dropping.
    If you didn't check your line and remove amplifiers, splitters, attenuators, do it now. If you already have, then I'd have your isp check your line.

Forum Discussion

Random Internet Disconnection on Both Wi-fi and Wired (CM1200 Modem)