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