Mild science, tech news, stories, reviews, opinion, maps and humor

23 April 2010

Blue Box - The Free Information Society

Blue Box - The Free Information Society

Any idea what this is? Circuit diagram (schematic) says Copyright 2001, Whirlwind Software, lower right-hand corner and in the middle right is "2-chip Blue Box" and . Size is 25.354kB pdf file, says "for experimental purposes only, not to be used for toll evasion"!!!

1 comment:

  1. A blue box is a device that was used to make long distant calls for free. When telephones used to be all wired, users were charged a 'toll' for a non-local call, based on the distance, and the length of the call. It could be quite expensive, and business set up "toll-free" 800-numbers for customer's convenience. Since using a blue box is theft of service, the author wrote that disclaimer ""for experimental purposes only, not to be used for toll evasion"

    Blue boxes emulated the audio tones used the phone company for routing calls -- similar to the tones you hear with a touch-tone phone, but a different mix of frequencies. Each of the 'tones' is made up of 2 frequencies. If you look back at the schematic, you can see a row of switches at the bottom, labeled 1,2,3, etc. Frequencies are measured in Hz - cycles per second. If you follow the lines, you can see that closing switch 1, would complete the circuit to generate a mix of tones 900Hz and 700Hz, switch 2 would complete the circuit for 1100Hz and 700Hz. The frequencies are specified on the diagram. From there, the 2 big chips each act as an oscillator for the desired frequencies...based on the voltage on pin 6. Finally, the 'tone' comes out of the "Telephone Handset Speaker"

    All of this circuitry was typically assembled into a little box with a keypad of switches and little speaker. It be used by holding the speaker up to the microphone of a telephone headset, and pressing the buttons.

    Speaking of blue boxes, Steve Jobs and Steve Wozniak built them before creating Apple computer:

    - Pulseburst Flow


Comments are most welcome! Some HTML is available for style and also for those with no style whatsoever.