The cpr all in one call blocker is easy to set up and easy to use you decide who you want to speak to the cpr all in one is the only call blocking product to have its own its built in 39rogue calling numbers list39 supplied by the call prevention registry which prevents silent calls robo calls recorded messages overseas call centres harassment calls malicious calls junk faxes and withheld numbers companies which are selling by phone using overseas call centres and automated sales