The handset on my BT 8500 occasionally resets itself on an incoming call - it stops ringing and the screen shows the BT logo. The behaviour is identical to that when removing and replacing the batteries so I assume it's the power-on-reset routine. Once it's back up and running, if the caller is still on the line it may reset again. The upshot is I can't answer the call. It seems to be dependent on the caller ID - one caller in particular almost always causes the issue. This is an allowed number too. The other day it happened with an announced call. The batteries are fine, they are the originals and two years old but read 1.45v and the battery indicator shows full. Can anyone help please?