Even more advanced call blocking block by number the bt8500 can block 1000 individual numbers meaning that you really can avoid speaking to the people you donrsquot want to block by type with the bt8500 you can choose the type of calls you want to block for example mobile international withheld unknown or payphone numbers can all be blocked plus you can even block numbers by area code or suffix do not disturb for those times when you just want some peace and quiet switch on do n