>> they tell me they plan a firmware update for December.
Thanks for that info.
>> "I'm a phone engr not an Internet guy but I'll have a go
Glad that hes reset your IPporfile. Not so good that he wasnt able to rectify the fault the same say. Hopefully he has arranged for someone to come who can access the required areas.
>> Idea: until the fault is fixed, if I fit Zyxel modem and clamp the d/s rate to say 4MBPS using a QoS clamp,
Not sure if QoS would do the trick. Im not familiar with your router, but it would be the sync speed you would need to reduce. QoS normally only affects the throughput, so youd still have the sync overhead.
The way to cut down on your sync and lessen the chance of the DLM kicking in too hard would be to lower the sync by increasing the SNR Margin. BTor set the SNRm to 6dB by default and dont seem to bother with SNRm changes (unlike the BTw DLM).
Some routers have the ability to change the target SNRm and this works on BTw based DLMs.
I dont know if the BTor DLM would respond to a target SNRm tweak to say 9 or 12 dB. Some have tried lowering it to 3dB which doesnt work and the DLM has over-ridden it. However Ive not know anyone attempt to increase it.. so you'd be the guinea pig if you did try it. Increasing the target SNRm (if it works on BTor) is the best way to artificially lower the sync for stability until another engineer gets around to fixing things properly.