Phone handset beeping

[Gissing]

The handset of my landline home phone has started beeping repeatedly when it is on its base/rest. Is there a way to stop this? I have tried replacing the batteries in the handset, but this has made no difference.

[boxtops]

Do you still have the manual? If not, is this the base station? I wonder if it's become unplugged at the mains.

[Prudie]

If you do have the manual try finding a reset, that usually clears a lot of odd problems with mine.

[Gissing]

Not the base station; one of the two subsidiary phones. Had already replugged at mains, reset, tried all the manual's options as far as we can see, but no joy.