Telephone privacy protection system

摘要

A central station blocks calls for a subscriber. The central station receives a call from a caller and provides an audio message to the caller requesting that the caller provides a first indicator if the caller is an unwanted caller or a second indicator otherwise. The central station receives the first indicator or the second indicator. If the central station receives the first indicator, the call is blocked. If the central station receives the second indicator, the call is passed through.