CallStop uses whitelists that each person manages. When an unknown caller calls you, they hear, "You have reached a phone number protected by CallStop. If you k

CallStop uses whitelists that each person manages. When an unknown caller calls you, they hear, "You have reached a phone number protected by CallStop. If you know this person, press 1 to send a whitelist request with a quick note. If you have a PIN to reach this person directly, press 2 and enter the PIN." Your contacts are your default whitelist to begin.