07-10-12, 12:19 PM
The only clue I can offer is that the ringing takes more current than when the phone is answered. So a bad connection can sometimes let the phone ring once but then the connection breaks down. Just the opinion of a total non expert on this subject, but that happened to me after I had stuck a spade through the under ground cable. Worked ok after I repaired it but then a few weeks later the damp got in and the above fault happened.