Really feel your pain and have been there ![]()
Never used to have a good word for BT, after they wired up our ISDN system back to front years ago, but more recently they've been pretty good.
We had similar issues to yourself with intermittent outages which was very frustrating, like you we replaced the router, and when the internet was down, the voice line was fine.
We had an engineer on site, and I'm trying for the life of me trying to remember any jargon which may be useful ![]()
He said to us (in laymans terms) the problem is at the exchange, and there is a setting which can adjust the Signal to noise ratio. By default it is set to X, but for us he tried setting it to Y. That was over 3 years ago and we haven't had a single problem since. I've no idea what X and Y are, but X is whatever the normal setting is for SNR at the exchange.
I had to report the fault a number of times, but the winner for us was when they did some diagnostics (magic wand/pixie dust?) while our broadband was down, which prompted them to come out and make the tweak at the exchange.
I did get lots of technobumble and told they shouldn't have to make the adjustment, and every other business in the same building with their own independent BT line was fine. But make the change they did, and touch wood, we've been problem free ever since.
Intermittent broadband is on a par with an unreliable car for frustration and stress factor!


It is nice to see a near continual fall in fuel prices and with supermarkets trying to out do each other, it's nothing but good news for the consumer.