Thanks Andrew. I'm trying to change the 'line standard' from ADSL to G.DMT in the HG 532 but can't see how to do this, ie nothing 'clickable'.
when I first put a home router in on my longish line (at least 5km) and it was connecting using ADSL2+ (@4mbit) I had to manually set a.gmt to get stability (@3.5mbit ish)
The router was set to multimode but was choosing the ADSL2+ option, and it needed the a.gmt for stability.
Maybe this is what the forums bod was thinking of.
However, as Andrew says, it sounds like yours is using a.gmt already.
Have you done all the other tests (test socket/ring wire etc)?