Mastodawn

Kevin McDonald Jun 18, 2025

Long before the internet, some phone networks were hackable by playing a single tone at 2600Hz.

Whistled into a phone, it could grant you unrestricted access. Do you have the vocal chops to be an old-school phone phreak?

I built a web app to test your ability to produce the legendary frequency. You won't get free long distance calls but you will get some honor in the knowledge that you could have been a cool hacker. 😎

I am sad to say that I can only whistle up to 1100Hz... But my wife (a long time woodwind player) is able to consistently get it.

Give it a try: https://phreak.kmcd.dev/

#phreaking #2600Hz #bluebox #RetroComputing #hacker #infosec #Tech

Phone Phreak Emulator

Test your phreaking skills by hacking this phone line.

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Ian K Tindale Jun 18, 2025

@sudorandom when was this ever true? The earliest phones I remember in the 1960s used carbon microphones but had no awareness of tones anywhere in the system, at least from the GPO phone in the hallway by the door. You could dial by imitating clicks by pressing the hook in and out several times, but there was absolutely nothing to do with tones about a phone.

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Marty Fouts

@u0421793 @sudorandom It wasn’t something a phone did. It was a form of “in band” signal that the GPO (AT&T in the US) used to communicate between central office (CO) equipment to control routing and billing of automated long distance calls. It was how the GPO eliminated the need for long distance operators.