CaptchaCall

It's actually quite simple really and I'm surprised this hasn't been set up yet. What you would do is phone carries will provide an option to set up a small captcha option on to existing phone plans. Much like you have the option to set up a mailbox or forwarding on your home phone and cell phones this could be set up the same way for people, just an added option when setting up or editing through your phone, so that way people of all ages could use this.

How it works is similar to how spamblockers for making online accounts work. The phone company sets up an option that makes it so before someone can make a call to your number, or rather, before that call can be received by you they must enter a 4 digit code that is randomized. Here's how it would sound calling someone's phone where this is set up:

1. Person dials the recipients phone number.
2. "This person has set up CaptchaCall to stop automated callers from calling, to reach this person please dial this four digit number... #.#.#.#." This could be shortened or phrased differently if you'd rather.
3. a. If you need to hear it again you can press 1. b. If dialed correctly then the call goes through. c. If dialed incorrectly it can immediately hang up or say "you have dialed this incorrectly, please hang up and try again." d. If the same number calls and gets the captcha incorrect a certain number of times that number will be automatically blocked and the owner of the line will be notified via email or mail.

This could be created and rolled out very quickly and the explanation behind it would be more straight forward than anything else, very easy for elderly clients to set up and be made aware of.