The latest home answer-phone from BT ( BT 8500 ) does the same thing. If the caller is not in your phonebook memory or not on your "allowed list" it intercepts the call and asks the caller to give their name followed by # key. The phone then rings you and asks if you want to accept, reject or ban the call now or permanently. I've had it for 2 weeks & touch-wood I've gone from 2 to 4 a day to nil. It's about £60 from places like Argos.