The history of early personal computing is interwoven with that of phone phreaking, where people would try to figure out ways to take advantage of the automated phone systems becoming common.
One popular trick was trying to figure out the special sequence of touch tones required to gain access to free phone calls. It was laborious work, but with the arrival of the Apple II computer, John Draper, a famous phone phreaker and Apple employee, decided a computer could do the job much more easily.
In this article republished from the Oct. 1, 1984, issue of Infoworld, Apple co-founder Steve Wozniak describes the trick.
An Apple For The Captain
By Steve Wozniak
The best prank I've seen with the Apple was played by Cap'n Crunch. John Draper, one of Apple's first employees, was responsible for designing a telephone board for us. Much more than a modem, the board could send touch-tone or pulse dial data; it could also transmit any tones that were programmable down the line, listen for specific sounds and a bunch of other things.
At one point Draper was motivated to crack the WATS extenders that are used by companies with incoming and outgoing free 800 lines. Company executives call in on the incoming 800 line and tap out a fourdigit code, which gets them on their outgoing 800 line. Then they can dial a free call anywhere they want. The only system protection is the four-digit code.
It would take a long time to dial ten thousand phone calls manually, searching for the extender code. But Draper had designed this new telephone board, and he knew a bunch of companies that had WATS extenders. He programmed the Apple to call the company on its 800 number, automatically get to the WATS extender, type out a four-digit code and check to see if the attempt succeeded or failed. The Apple with the board would listen to all the tones on the phone line to determine when it was ringing, when it went to the WATS extender, and so on.
It took about ten seconds for the Apple to dial the call and try a new four-digit code. The Apple would restart and try it again. And then try the next number. It was able to dial about five thousand calls a night-the average number of calls to crack a WATS extender. Draper cracked about twenty WATS extenders, averaging one a night.
The city of Mountain View, California, where he lived at the time, keeps an index of how well the phone system is working. An average of 30 percent of all calls made from the city don't go through. The month Draper was cracking the WATS extenders, the index jumped to 80 percent! For that month Draper made more than 50 percent of the calls originating from Mountain View, California, whose population is over sixty thousand ...