What has been eliminated:
All recent testing has been from the test socket.
Filter - several been tried - last engineer's visit I gained a filtered faceplate.
Routers - two TG582n's with three different firmware versions
Telephones - DECT and wired. However fault still occurs even if there is no phone plugged in at all!
Last visit the engineer disconnect my master socket and clipped his tester on to the bare incoming wires - still seeing CRC errors when the phone rang.
However the absolute killer fact is that he disconnected my line inside the exchange and connected his tester there - he still saw loads of CRC errors when the line was rung. That eliminates E side, D side and everything at my end.
They've done multiple lifts and shifts.
The response from BTw was that it's a known issue with Marconi 20CN exchanges and I have to lump it!
Plusnet user since November 2001