I built something thing like this using Twillio for my Caller ID test tool. Visiting the site creates a unique pin number and you have to call in and enter it.

I built something thing like this using Twillio for my Caller ID test tool. Visiting the site creates a unique pin number and you have to call in and enter it. http://www.calleridtest.com http://www.calleridtest.com Twillio makes the development of things like this a breeze.