Now that is some archaic technology, telephone tones! Wasn't there a time when you could make a certain frequency tone and you could get free calls with a pay phone? This was before my time, but I've heard about it. Mark Wozniak former of Apple Computer found the toy whistles you would get with Captain Crunch cereal would make the exact tone for a 25 cent call. He was shown this trick from his friend John Draper.