ADSL connects only when phone is in use

My parents have a bizarre problem. Their ADSL used to work fine but now it doesn't sync.

I discovered by accident that it will sync (and stay synced and connected) if they're making a telephone call. As soon as they hang up the phone, the ADSL loses sync again.
This is repeatable.

Anybody got any idea what might be wrong? I've checked the installation - the microfilter is in the right place (at the master socket, between the socket and the internal house phone wiring).

Help!

One of the BT guys will know and respond I'm sure. I think I've seen posts calling this a wet joint. The additional current used by a phone call is enough to "weld" a temporary good connection in place. I've quite likely got this wrong but it's worth searching the archives.

edited to add:

I just searched for wet joint and the term seems to be referring to something else. So you may safely ignore my post.

Edited by deleted (Sun 07-Oct-07 12:50:30)

I don't think you are far out except the additional current used by the phone is called a wetting current http://en.wikipedia.org/wiki/Wetting_current

common phone line faults

I have had the same happen to my line, although just leaving the phone off the hook was usually enough to be able to connect, and sometimes ringing the phone from my mobile would get the ADSL working when the line was completely dead with no dial-tone.

Edited by AbandonShip (Sun 07-Oct-07 13:54:23)

I was probably dreaming.

Kitz desribes that problem on her site - http://www.kitz.co.uk/adsl/connectionprobs.htm , other guys on the right lines (cough) re water.

I had something very similar when I first got ADSL.

It turned out to be rust or a bad connection in one or more of the 3 connectors on the wires immediately outside the house just before the master socket.

The BT guy cut off the connectors, re-pared the wires and put in 3 new connectors which solved the problem.

I used to have to leave the phone off the hook to get a connection.

-- gyre --