The BT Telephone BT 1700 Nuisance Call Blocker Digital Cordless Home Phone gives you back control over which calls you want to take and which you want to block. The BT 1700 can block 20 individual numbers, meaning that you really can avoid speaking to the people you don't want to. The BT 1700 boasts excellent sound quality, a built in digital answering machine and is easy to set up. You must subscribe to a Caller Display service from your network provider for the block nuisance calls feature to work. Charges may apply.