Unfortunately there's nothing you can do to fix an upstream noise problem. The device you posted is something that would be implemented in the cable plant not in your home. Even if you could obtain one it would do you no good whatsoever.
Cox has stated that they're aware of the problem. But you should know that noise on a DOCSIS network can be like a needle in a haystack especially when it's intermittent. It could take them quite a while to identify which device or house is feeding noise on to the line. In the meantime, there's no amount of research you can do or questions you can ask that will help them or help you. All you can do is ask them for a current status of the issue. You've fixed everything on your end. Now it's up to Cox to fix their end. They know what the problem is but finding the source of that problem could be very difficult.
Its been going on for 10 years now. Its not until recently I started really doing some digging.
I don't see it ever getting fixed. I guess I'll have to move sooner than expected lol
