2600 - Captain Crunch

Do you remember Captain Crunch? Not the cereal guy. The guy that took the toy whistle out of the cereal box and started messing with the phone company.

Way back when I worked for the phone company, the phone company used 'in band' signalling to communicate between long distance exchanges. The 'in band' frequency was 2600 hertz. (cycles back then) (I still say cycles)

So this guy found out that he could use the whistle (which blew a perfect 2600 Hz) to fool the equipment into thinking he was the sending equipment. He would whistle the 2600 hertz tone which would drop the far ends receiving equipment but not the near ends transmitting equipment. So he would have an open ended transmission circuit.

Then he would use a 'blue box' to dial anywhere in the world for free. You could say he was the original hacker.

Most phone companies now use a separate signalling channel called SS7 so the whistle doesn't work anymore.


Wikipedia still amazes me. All this information and more is available on it.