Thorough test of a telephone fault

Published 26/05/2004 10:24   |    Updated 13/02/2009 13:09
How do I perform a thorough test of my telephone setup?

If nothing previously mentioned  identifies your phone problem, it’s time to carry out a thorough test.


  1. Unplug all the devices from your telephone sockets
    Disconnect anything plugged into your sockets. If you have broadband, unplug your microfilters and broadband modem/router.

  2. Test your main socket
    Find your main socket (usually located where the line enters your property). Test it by plugging in a telephone with a cord.

  3. If you have no problem at the main socket
    If the phone works on your main socket, the fault is probably with a piece of equipment. Try plugging them in one at a time, checking the line after each one. If the problem recurs with one in particular, consult the manual it came with.

If consulting the manual doesn’t help, and your landline handset is under a 12 month warranty and was bought from BT, then you need to contact Customer Care on Freephone 1904. If you bought your landline handset from any other retailer you will have to contact them directly.


  1. If there is a problem at the main socket and it has a horizontal bar across the front
    If you have a phone master socket like the one in the photo here (that is, square with a horizontal groove halfway down it, and removable upper and lower covers), we recommend you remove the lower cover as shown, taking care not to dislodge any wiring.



Do not remove the upper cover. This will reveal a test socket on the right-hand side.

To do this, unscrew the face plate of the socket and the bottom half will slide out (fig. A). Behind it, on the right hand side, you’ll see the test socket (fig. B).


N.B. If your main socket has no horizontal bar (fig. C), skip to step 6.


  1. If you have no problem on the test socket
    If your phone works when you plug it into the test socket, it’s quite likely that your internal wiring is faulty.


  1. If there’s still a problem at the test socket or the main socket
    To be certain that the problem is with the line (not the phone you’ve used to test it), check the test socket with more than one phone. If you find that it still doesn’t work, there may well be a fault with the network and it’s time to contact BT Ireland to report the fault and if deemed necessary after a remote diagnostic test, arrange a visit from a technician.


If your telephone line rental is paid to BT Ireland then call Freephone 1904 from a mobile or another working landline. Alternatively you can report the fault via email  by clicking on Ask a Question.


You can also report and track a fault online by logging into your account.


See also: Repairing the fault - know your rights


Please tell us how we can make this answer more useful.