Phreaking
While Draper was driving around his Volkswagen Microbus to test a pirate radio transmitter he had built, he broadcast a telephone number to listeners as feedback to gauge his station's reception. A callback from a "Denny" (identified in the Discovery Channel documentary about Hacking as Denny Teresi) resulted in a meeting that caused him to blunder into the world of the phone phreaks. Teresi and a large percentage of the phone phreaks were blind. Learning of his electronic capability, they wanted him to build a multifrequency tone generator (the blue box) to gain easier entry into the AT&T system, which was controlled by tones. Then they would not have to use an organ and cassette recordings of tones to get free calls. At least one of the blind boys called Joybubbles had perfect pitch and had identified the exact frequencies. They informed him that a toy whistle that was, at the time, packaged in boxes of Cap'n Crunch cereal could emit a tone at precisely 2600 hertz—the same frequency that was used by AT&T long lines to indicate that a trunk line was ready and available to route a new call. This would effectively disconnect one end of the trunk, allowing the still connected side to enter an operator mode. Experimenting with this whistle inspired Draper to build blue boxes: electronic devices capable of reproducing other tones used by the phone company.
I don't do that. I don't do that anymore at all. And if I do it, I do it for one reason and one reason only. I'm learning about a system. The phone company is a System. A computer is a System, do you understand? If I do what I do, it is only to explore a system. Computers, systems, that's my bag. The phone company is nothing but a computer. — Secrets of the Little Blue Box, Ron Rosenbaum, Esquire Magazine (October 1971)The class of vulnerabilities Draper and others discovered was limited to call-routing switches that employed in-band signaling, whereas newer equipment relies almost exclusively on out-of-band signaling, the use of separate circuits to transmit voice and signals. Though they no longer serve a practical use, the Cap'n Crunch whistles did become valued collector's items. Some hackers sometimes go by the handle "Captain Crunch" even today; 2600: The Hacker Quarterly is named after this whistle frequency.
The expense of sustaining the unbilled phone calls, the redesign of the line protocols, and the accelerated equipment replacement due to the blue box is difficult to calculate, or even to separate from something as complex and dynamic as the telephone long-distance network.
The 1971 Esquire article which told the world about phone phreaking got Draper in hot water. Draper was arrested on toll fraud charges in 1972 and sentenced to five years' probation. The article also brought him to the attention of Steve Wozniak, who located Draper while working as an engineer at KKUP, a Cupertino public radio station located near the future Apple campus. In the early and mid 1970s he taught his phone phreaking skills to Steve Jobs and Steve Wozniak, who later founded Apple Computer. He was briefly employed at Apple, and created a telephone interface board for the Apple II personal computer, which he named "The Charlie Board". Wozniak has said the reason the board was never marketed was that Wozniak was the only one in the company who liked Draper, and partially due to Draper's arrest and conviction for wire fraud. While at Apple, Draper also wrote a cross-assembler used by Steve Wozniak while developing Apple I and Apple II.
Read more about this topic: John Draper