Thanks so much for your original posting - it gave me a clue as to how to solve an intermit BB connection which I'd been in contact about with AOL and BT for the past 4 days and with no success.
I've had BB for over 2 years using the same extension socket - then last Thursday the connection was lost. But strangely it was regained when ever the phone was in use!
I took your advice and went to the master socket and disabled all extension wiring connections from there (it was so old it did not have internal extension connector you speak of). That done I ran brand new cabling just from the single master socket and fantastic every thing works again.
So over the past few years my buried under the floor board cabling had somehow decayed.
I'm going to suggest AOL help desk reads your postings in the future.