In reply to a post by MrSaffron:

The Reverb Misdirection seems to be an error being spotted in how timing is handled, and timing is a key part of keeping DSL operating.

It looks to me like C-Reverb1 is a portion of training. If a resync happens because of a failure during the training phase ... then presumably *that* training was part of a resync for a different, earlier cause. Therefore we could be in the midst of a sequence of resyncs. We might be able to tell if the UAS counter goes up by significantly more than around 25 seconds.

As far as I can make out, C-Reverb1 looks to be a state where the central DSLAM is mostly listening to the user's modem, listening for a pre-determined string of symbols, and trying to set AGC so it can hear correctly. In such a state, you'd guess that a "misdetection" meant that the DSLAM failed to detect that string of symbols with any AGC settings.

Perhaps the user's modem is faulty. Perhaps the line is faulty.

Thanks WWWombat

My line was "repaired" and since the "repair" i've had nothing but trouble.

Previously, upstream and downstream SNRm were both on the 6 dB range and following the work upstream is 16 dB + and downstream is anywhere from 6 to 16 dB.

I don't know what they did but at least before they "fixed" it my line was stable.

Will see if i get a sympathetic engineer thursday who can help.

Quick update.
OpenReach engineer just been.
He sorted out the SNRm upstream issue and i'm now back to 1.2 up with a SNRm of 6.3
Persistence has paid off in the end.

fingers crossed it lasts this time.