While you wait for answers, we may have found some information which could help you.
Success
Message
Mute?
Problem with handsets?
How do i clear the TAM?
TAM FULL on Binatone 1420 Single, base holds old messages th?
Fix blank screen in cordless hand set CLP99483?
BT 4600 twin one handset bot ringing?
Battery cover?
BT Studio 4500 cordless telephone?
How can i get my handset to speak with the caller?
How can I repair my phone?
Bt 4600 phone?
How can I mend my BT4600 (1+1) phone?