Occasionally, say 1 in 100 incoming calls do not produce a 'ring' in the house. This was about 1 in 20, but following advice found here and on other sites, I disconnected everything from the BT incomer, and tested that with a simple handset calling 'home' with my mobile. I then progressively replaced filters, then phones, the ADSL modem and computer. I replaced 2 out of 4 simple handsets, and an answering machine. The items were all working, but if I rang 20 - 30 times I got at least one failure.

To the person calling the phone appears to be ringing out, but woth no pickup from me or the answer phone. Obviously, if I call in a 'line fault,' BT will check once, get a ring tone, and say it's my problem. Is there a chance that the service does fail sometimes, now were all on broadband all the time? Help !

Look in phone jack(s), the gold pins and verify gold. Intermiddents can be caused by, bad Line cords, bad jacks, bad wires, bad filters or bad connections. Telco can have wiring problem also. Do you sometimes lose DSL?

I have already checked for possible corrosion. The contacts are all in A1 shape - clean and shiny. Any wiring extensions I have done have been redone The BT incomer is only a couple of years old, and is in a dry cupboard. The two wire connection from a junction box in the street was replaced following some damage.

I did have an intermittent problem with the DSL (ADSL light flashing, not solid), but this disappeared after I removed and replaced all the filters withouut changing any.

If Modem and all other equipment "Appear" fine, I would try a different pair if available.
One conductor can open in a bundle?

Thank you. I take your point, but will have to find someone 'freindly' in BT - a call out is £140 minimum if the fault is with me and not 'them.'... I suppose I could just open the BT jack at the house and find if there is another pair. There must be surely? It's an armoured cable about 5/8" diameter?