A cereal-box whistle that could trick the phone system into free calls
by Mark Frauenfelder from Boing Boing on (#788K2)

In today's edition of Dan Lewis's excellent Now I Know newsletter, there's a photo of a red plastic whistle that used to come in boxes of Cap'n Crunch cereal in the 1960s. Besides being a cool-looking whistle, it had a unique property that made it popular among phone hackers. - Read the rest
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