Before you contact BT, could you try connecting to the test socket if you have one?
The connection speed is fine, its just the DLM which has set the target SNR too low, its a very common problem.
Yes, but the DLM sets the SNR margin to 3dB, not 1dB. So, if the margin is higher in the test socket it could indicate problems with the OP's wiring.
My earlier post was saying I've contacted the care team.
arobertson, I don't have a test socket. My outlet is an old double socket.
The trial was to reduce the target SNR from 6dB to 3db, and started last Autumn. Also the interleaving depth was increased.
The idea was to increase the connection speeds slightly on stable lines. It has however caused some problems on lines, when the level of radio interference causes this margin to drop too low in the evening.
This has resulted in an increase in uncorrected errors (CRC events), which are effectively reducing the download speeds.
The solution on these lines, is to set the target SNR back to 6db. This is under the control of the BT Care Team, and we can refer people to them, if we decide that its the best way forward.
It's not a trial, it's part of 21CN DLM. It happens on ALL 21CN connections if the connection is stable enough.
The SNR should be 3dB in the day, not 2dB so that is why I suggested connecting to the test socket to see if the SNR was higher there.