I've had gfast for about 6 months and its been great until about a month ago. The line keeps disconnecting, ringing 17070 and just listening to the blurb seems to force it back up OK. Its an old handset but the line does sound a little noisy. Line speed is fine though. Stats from the smarthub 2 :-
if you can hear any noise on quiet line test then you need to report a phone fault and get it fixed
Probably a high resistance connection. especially if you do not use your phone very often.
Passing a current through the line, usually fixes the problem for a while. Even better, ringing the home phone from a mobile and letting it ring for about 20 seconds before answering, works best. The incoming ring is a high voltage, and also operates a number of mechanical bypass relays on the fibre cabinet port.
High resistance connections can be caused by bad joints, or relay contacts which have become "dry".
That's interesting @Keith_Beddoe. I believe this might explain the problems I reported on these forums while ago that I had crackle on the line, but only occasionally and is resolved by disconnecting and reconnecting the telephone from the socket and making a few calls etc. I've changed the cables, and now just changed the phone as well this month, just in case but still get occasional disconnects (seems a little more regular now ).
As I can go days without a disconnect I haven't worried too much about it, and it would be difficult for the engineer to find I suppose if its only intermittent.