Cap'n Crunch Whistle

Cap’n Crunch bo’sun whistle

I had a Cap'n Crunch whistle. Or as the whistle itself says, a "Cap’n Crunch bo’sun whistle".

Wanna hear how it sounds? Now compare the whistle’s sound to a pure 2600 Hz tone.

Cap'n Crunch whistleBack in 1971 Cap’n Crunch cereal gave away a plastic whistle called the Captain Crunch whistle. If you blew the toy in the cereal box it made a 2600 Hz tone.

A 2600Hz tone is special. People quickly learned that blowing a Captain Crunch whistle into a phone made free long distance phone calls. The sound of a Cap'n Crunch whistle’s mimics one used by the phone company’s switching equipment used back then.

A tone at 2600Hz told the AT&T long lines that a trunk line was ready and available to route a new call. In other words, blowing a Cap'n Crunch whistle sidestepped the phone system’s billing system back before digital phone switching (ESS) was introduced. This was called “whistling off”. Blow a Cap'n Crunch whistle into a phone and make free long distance phone calls! Remember, this was back when long distance calls were expensive, unlike today.

Timex-Sinclair & Capn Crunch whistleJohn Draper, Joe Engressia, and Bill from New York were pioneering phone phreakers who played with Cap’n Crunch whistles. Mr. Draper later went on to construct blue boxes, another phone phreak gadget.

My introduction to such matters took a quantum leap forward when as a young, impressionable high schooler I read Secrets of the Little Blue Box by Ron Rosenbaum, Esquire Magazine (October 1971) and the infamous June 1972 Ramparts magazine article (PDF) on how to make a black box. (Can you say 'Radio Shack project'?)

A big shoutout to Michael at Wall of Sound for jogging my memory, which inspired me to put this page together. Hats off to the producers of a television show on phone freaking that stumbled across this page and borrowed my Cap'n Crunch whistle so Woz himself could blow it at the Tech Museum of Innovation in San Jose. I don’t know if the show ever aired but I was promised a credit. (I’m holding my breath.) Hey, we talked on the phone, I sent it to them and it came back.

Speaking of phones, this page has the pure DTMF tones themselves. Matt Blaze described using a C tone to break wiretaps. Dated so I’d check before using it. Not that I recommending doing any such thing.


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