This challenge is to devise a system that blocks robocalls. The call screening phone described herein not only blocks all robocalls, but has the added benefit of screening out other types of undesired calls as well.

The operation begins when the phone receives an incoming call, at which time the phone plays Message 1 to the caller, but not to the callee, so as not to disturb the latter. Message 1 consists of three parts, each with a specific purpose.

The first part identifies the callee, and is designed to screen out callers who have dialed the callee’s number by mistake.

The second part informs telemarketers that the callee is not interested in their product or service.

The third part is a challenge question, which is designed to block robocalls. In also screens out calls made by children playing with the telephone and dialing numbers at random.

An example of a Message 1 is the following:

This is the John Doe residence. If you are calling to sell a product or service, ask for a donation, or conduct a survey, then we are not interested. Otherwise, enter the number of months in a year.

The challenge question must require a numerical response and be one that a human caller can easily answer, but be beyond the capability of any automated system that could be cost-effectively used for robocalling.

If the caller enters an incorrect response to the challenge question, or fails to enter the correct response within the time allotted (5-10 seconds should be sufficient), then the phone hangs up. Otherwise, the phone rings, and from this point on, the call screening phone behaves like a phone with a built-in conventional answering machine.

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