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Forum Discussion
ndpatacsil01
Aug 08, 2018Aspirant
Cm500 disconnection issues constantly
Hello just bought this to replace my Optimum/Cablevision modem.
However, getting lots of issues with it where internet connection will be okay then reset after 10 min over an over.
It was registered okay with the ISP. I have had about 3 phone calls at great length.
Optimum says the line is fine. They see my modem registered on their end. It must be a modem problem.
So I am here today to see if it is the modem problem or not. How can I rule it out?
At times my upsteam is locked at one channel. Then at 4 channels.
I get T3 and T4 errors.

Cable Connection
5 Replies
- vkdeltaNETGEAR Employee Retired
Pls post even logs.
#1. Most likely one of of your US channels has noise and thats why you may be seeing 1 missing US channel.
#2. Your DS channels have noise and thats why you are seeing uncorrectables.
You may want to fix your cable. Do you have bad cable, connector or bad splitter at home?
- ndpatacsil01Aspirant
Thanks for the reply.
I live in an apartment and the cable comes from outside wall into my living room.
I tried to see where the splitter is located but I could not reach it. It is in between two buildings in a narrow alley.
But pretty sure splitter is used. My landlord downstairs also has optimum. As far as I know they have no issue.
Please see logs:

- vkdeltaNETGEAR Employee Retired
If you see your log, there are lot of T3 and T4 timeouts. they will cause intermittent disconnects.
Have you looked at the connectors at your house? are they are in good condition and not loose, etc?
- vadim125Aspirant
Hi,
Looks like i am having similar issue. I change cable modem from optimum provided one just over a month ago. Optimum modem had no issues for years but cm500 so far lost connection twice, about 2 weeks apart. T4, T3 and timing synchronization issue from the log. cables look like in good condition. there is only one split at the house entry and few meters runs. firmware is 1.01.04. i know 1.01.05 is recomended. i dont know if this is related. Considering that this is not happening often i dont think this is cable related. Very annoying.
Below log from today:
Time
Priority
Description
2018-8-8, 16:21:14
Critical (3)
Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=a0:04:60:bd:23:80;CMTS-MAC=00:01:5c:95:b6:77;CM-QOS=1.1;CM-VER=3.0;
2018-8-8, 16:21:43
Critical (3)
No Ranging Response received - T3 time-out;CM-MAC=a0:04:60:bd:23:80;CMTS-MAC=00:01:5c:95:b6:77;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:20
Critical (3)
SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=a0:04:60:bd:23:80;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:26
Critical (3)
No Ranging Response received - T3 time-out;CM-MAC=a0:04:60:bd:23:80;CMTS-MAC=00:01:5c:95:b6:77;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:32
Notice (6)
Honoring MDD; IP provisioning mode = IPv4
1970-1-1, 00:00:34
Warning (5)
DHCP WARNING - Non-critical field invalid in response ;CM-MAC=a0:04:60:bd:23:80;CMTS-MAC=00:01:5c:95:b6:77;CM-QOS=1.0;CM-VER=3.0;
2018-8-8, 17:56:59
Error (4)
Missing BP Configuration Setting TLV Type: 17.8;CM-MAC=a0:04:60:bd:23:80;CMTS-MAC=00:01:5c:95:b6:77;CM-QOS=1.1;CM-VER=3.0;
2018-8-8, 17:56:59
Error (4)
Missing BP Configuration Setting TLV Type: 17.9;CM-MAC=a0:04:60:bd:23:80;CMTS-MAC=00:01:5c:95:b6:77;CM-QOS=1.1;CM-VER=3.0;