While you wait for answers, we may have found some information which could help you.
Click here for Lost Manual FindBT Studio 3500 base problem?
BT Studio 1500 triple set?
bt 1100 twin need to replace broken 2nd handset?
How do I connect my own answering machine?
Beeping phone BT Studio 1100?
Bt 3500 cordless tel/answerphone?