The Cyber Crime Hall of Fame Sep 9, 2008, 18 :31 UTC (2 Talkback[s]) (3613 reads) (Other stories by Corinne Iozzio)
"In the 1970s, Draper used a toy whistle found in Cap'n Crunch cereal to hack phone lines and make calls. Draper realized the whistle produced the exact tone necessary to signal that an active call on a phone line had ended—2600 Hz, to be precise—when in fact it had not, thus allowing the call to continue even after the exchange thought it had ended."