Orbi WiFi 7 RBE973
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CM1200 disconnects multiple times daily

aramia
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CM1200 disconnects multiple times daily

We purchased a CM1200 modem in early 2021 to pair with our new Cox Gigablast service, and it worked admirably for the first year and change--no real issues of note. At some point in the last few months, it's taken a turn for the worse and is now barely functional. Our connection drops out at least 10 to 20 times a day and is extremely slow to recover, which makes almost any activity requiring a long-term stable connection impossible. After several months of frustration, we were finally able to have a Cox tech come to our home, though he wasn't able to figure out the source of the problem. My understanding is that he adjusted some cables at the edge of our property and called it a day, and it seemed like it might have helped for a day or two, but of course now we're back where we started and not sure what to try next. It'd be great to know for sure if the modem is shot or if there might be something else that we can try; obviously, replacing a gigabit modem is pretty expensive, and I don't really feel like we should have to throw this one in the trash after just two years…

 

Our event logs are full of messages like these pretty much all day every day:

 

Fri Apr 14 19:24:35 2023Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:06:43:e0;CMTS-MAC=44:ae:25:f6:6d:d1;CM-QOS=1.1;CM-VER=3.1;
Fri Apr 14 19:23:59 2023Notice (6)CM-STATUS message sent. Event Type Code: 24; Chan ID: 159 160; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0 2 3.;CM-MAC=38:94:ed:06:43:e0;CMTS-MAC=44:ae:25:f6:6d:d1;CM-QOS=1.1;CM-VER=3.1;
Fri Apr 14 19:23:24 2023Notice (6)CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=38:94:ed:06:43:e0;CMTS-MAC=44:ae:25:f6:6d:d1;CM-QOS=1.1;CM-VER=3.1;
Fri Apr 14 19:23:15 2023Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:06:43:e0;CMTS-MAC=44:ae:25:f6:6d:d1;CM-QOS=1.1;CM-VER=3.1;
Fri Apr 14 19:22:50 2023Notice (6)US profile assignment change. US Chan ID: 8; Previous Profile: 10 13; New Profile: 9 13.;CM-MAC=38:94:ed:06:43:e0;CMTS-MAC=44:ae:25:f6:6d:d1;CM-QOS=1.1;CM-VER=3.1;
Fri Apr 14 19:21:56 2023Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:06:43:e0;CMTS-MAC=44:ae:25:f6:6d:d1;CM-QOS=1.1;CM-VER=3.1;
Fri Apr 14 19:21:24 2023Notice (6)US profile assignment change. US Chan ID: 8; Previous Profile: 9 13; New Profile: 10 13.;CM-MAC=38:94:ed:06:43:e0;CMTS-MAC=44:ae:25:f6:6d:d1;CM-QOS=1.1;CM-VER=3.1;
Fri Apr 14 19:20:35 2023Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:06:43:e0;CMTS-MAC=44:ae:25:f6:6d:d1;CM-QOS=1.1;CM-VER=3.1;
Fri Apr 14 19:17:42 2023Notice (6)US profile assignment change. US Chan ID: 8; Previous Profile: 10 13; New Profile: 9 13.;CM-MAC=38:94:ed:06:43:e0;CMTS-MAC=44:ae:25:f6:6d:d1;CM-QOS=1.1;CM-VER=3.1;
Fri Apr 14 19:16:57 2023Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=38:94:ed:06:43:e0;CMTS-MAC=44:ae:25:f6:6d:d1;CM-QOS=1.1;CM-VER=3.1;
Fri Apr 14 19:16:26 2023Notice (6)CM-STATUS message sent. Event Type Code: 24; Chan ID: 159 160; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0 2 3.;CM-MAC=38:94:ed:06:43:e0;CMTS-MAC=44:ae:25:f6:6d:d1;CM-QOS=1.1;CM-VER=3.1;

 

Other notes:

  • Modem has been restored to factory settings twice with no change.
  • Modem is connected to an ASUS AX92U router with a CAT6 gigabit ethernet cable. The router logs have quite a few entries along the lines of "Disassociated because sending station is leaving (or has left)", which seem to correspond to times when the modem is reporting T3 time-outs.
  • Downstream power levels are within -1 to +4 dBmV; upstream is right around 48. Extended Upstream Transmit Power is off, but the values are about the same when it's on (and reliability does not improve).
  • The coax cable coming from the wall to the modem looks undamaged, and there are no splitters or other devices attached to it. We do not have cable TV service.

Full cable connection details are below. Thanks in advance for any guidance!

 

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel801000000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
SecurityEnabledBPI+
IP Provisioning ModeHonor MDDhonorMdd(4)
 
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1LockedQAM25637801000000 Hz3.8 dBmV44 dB00
2LockedQAM25617213000000 Hz-0.1 dBmV39.7 dB53224
3LockedQAM25618219000000 Hz-0.5 dBmV39.4 dB76260
4LockedQAM25619225000000 Hz-0.5 dBmV39.2 dB92220
5LockedQAM25620231000000 Hz-0.4 dBmV38.9 dB13471
6LockedQAM25621237000000 Hz-0.5 dBmV38.8 dB340
7LockedQAM25622243000000 Hz-0.5 dBmV38.8 dB00
8LockedQAM25623249000000 Hz-0.5 dBmV38.8 dB00
9LockedQAM25624255000000 Hz-0.2 dBmV38.8 dB00
10LockedQAM25625729000000 Hz3.8 dBmV44.2 dB00
11LockedQAM25626735000000 Hz3.6 dBmV44.1 dB00
12LockedQAM25627741000000 Hz3.7 dBmV44.2 dB00
13LockedQAM25628747000000 Hz3.7 dBmV44.2 dB00
14LockedQAM25629753000000 Hz3.8 dBmV44.1 dB00
15LockedQAM25630759000000 Hz3.6 dBmV44.1 dB00
16LockedQAM25631765000000 Hz3.7 dBmV44.2 dB00
17LockedQAM25632771000000 Hz3.9 dBmV44.2 dB00
18LockedQAM25633777000000 Hz3.9 dBmV44.2 dB00
19LockedQAM25634783000000 Hz3.7 dBmV44.1 dB00
20LockedQAM25635789000000 Hz3.8 dBmV44.1 dB00
21LockedQAM25636795000000 Hz3.8 dBmV44 dB00
22LockedQAM25638807000000 Hz3.5 dBmV43.8 dB00
23LockedQAM25639813000000 Hz3.6 dBmV43.8 dB00
24LockedQAM25640819000000 Hz3.6 dBmV43.8 dB00
25LockedQAM25641825000000 Hz3.5 dBmV43.8 dB00
26LockedQAM25642831000000 Hz3.7 dBmV43.8 dB00
27LockedQAM25643837000000 Hz3.7 dBmV43.9 dB00
28LockedQAM25644843000000 Hz3.6 dBmV43.8 dB00
29LockedQAM25645849000000 Hz3.5 dBmV43.8 dB00
30LockedQAM25646855000000 Hz3.5 dBmV43.7 dB00
31LockedQAM25647861000000 Hz3.3 dBmV43.7 dB00
32LockedQAM25648867000000 Hz3.3 dBmV43.3 dB00
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1LockedATDMA15120 Ksym/sec36800000 Hz48.3 dBmV
2LockedATDMA25120 Ksym/sec30400000 Hz48.3 dBmV
3LockedATDMA35120 Ksym/sec24000000 Hz49 dBmV
4LockedATDMA45120 Ksym/sec17600000 Hz48.5 dBmV
5Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
6Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
7Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
8Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
 
Downstream OFDM Channels
Channel Lock
Status
Modulation /
Profile ID
Channel
ID
Frequency Power SNR /
MER
Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1Locked0 ,1 ,2 ,3159300000000 Hz0.7 dBmV41.2 dB296 ~ 789514018642134050420
2Locked0 ,1 ,2 ,3160912000000 Hz3.3 dBmV43.2 dB1108 ~ 29871317563334150800
 
Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1Locked3 ,4 ,9 ,10 ,11 ,12 ,13636800000 Hz42.0 dBmV
2Not Locked000 Hz0 dBmV
Message 1 of 2
plemans
Guru

Re: CM1200 disconnects multiple times daily

Your logs are indicating a line issue. 

While your power levels are technically in spec, they're also indicating a line issue as the power should be fairly consistent with each channel. Yours isn't. 

Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, loose connections, bad/old/cheap connectors, or corroded connections. Replace them if you do.
If you can, simply connect the modem right where the coax comes into the home. This prevents wiring in the home from being the issue. And some ISP’s charge if the wiring issue is in the home. So this helps prevent this.

 

If none of that helps, then cox does need to check it again. 

Message 2 of 2
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