The phone rings. But no one is there.

Ghost calls have long been a staple of horror movies and urban legends about frightened baby sitters. Ray Bradbury wrote a teleplay about a telephone switch that reached sentience only to start stalking a person.

But the culprit behind what is becoming a common occurrence in some households may have a less than otherworldly explanation. More often than not it is a telemarketer — and one that complies with federal regulation. Indeed, adherence to the rules may be one reason for the ghost calls.

Most fingers point at telemarketers who use a predictive dialer, a device that makes hundreds of calls a minute and uses artificial intelligence to detect when a person actually answers. These are then connected directly to a telemarketer waiting to promote a new low mortgage rate, a political candidate or a once-in-a-lifetime opportunity. If no one in the cubicle farm is ready to start pitching, the predictive dialer just hangs up.

Speaking from firsthand experience, it is hard to get all the variables right in
predicting when a person has answered the phone and when you have an answering device, and so on, switching, timing, and other factors are hard to do in software....