Here's an example you're probably already familiar with. When your renewal credit card arrives, you're asked to phone the issuing company to let them know that the card is in possession of the intended customer, and not somebody who stole the envelope from the mail. The instructions with the card these days generally tell you to call from home. When you call, software at the credit card company analyzes the ANI, the automatic number identification, which is provided by the telephone switch on toll-free calls that the credit card company is paying for.