The concept is this… Phone company A owns the phone number that you call. Phone company B must rely on PC-A to deliver the call and therefore PC-B must pay PC-A a “nominal per minute charge” to connect the call. New phone companies, called CLECs, sprung up overnight to take advantage of this. They typically provided cheap or free dial-up modem access lines to ISPs, thus steering a large volume of calls with long call durations into their phone networks. In this arrangement, (lots of calls * long call durations) = $$$$$$$

I thought all this was dead, but apparently not in Iowa. The connect charge is typically very, very small (a fraction of a cent per minute) so I’m not sure how they can keep this in the black.