I wouldn't say 'capped.'
I would say on purposely restricted due to some noise / error build up. Generally things only get capped because of an issue somewhere.
a 13db noise margin is ever so weird though - especially after a resync. I expected 12 or 15db after a resync but all of the stats have been around 13db. This points more towards a cap on the sync and not a noise margin increase due to instability.
No mention of who the ISP is that I can see.
TEST socket isn't always the full story. PLENTY of times I've found that some extensions still work even when the faceplate is removed. So many houses have star wiring and a master stuck on randomly somewhere. Definitely worth a consideration.
Not only this but REIN or just poor quality wiring / a very long line from the exchange can often mean a 6db noise margin isn't stable (and this is beyond the users control).
Anyho, I'll stop butting in as much as possible.
Edited by ukhardy07 (Thu 13-Sep-12 19:26:26)