Joybubbles: the blind phreaker whom Whistler was based off of in Sneakers

As a five-year old, Engressia discovered he could dial phone numbers by clicking the hang-up switch (“tapping”), and at the age of 7 he accidentally discovered that whistling at certain frequencies could activate phone switches.[3]<p>A student at the University of South Florida in the late 1960s, he was given the nickname “Whistler,” due to his ability to place free long distance phone calls by whistling, with his mouth, the proper tones.