1972, originally in phone phreak, one of a set of technically creative people who electronically hacked or defrauded telephone companies of the day.
The phreaks first appeared on the US scene in the early 1960s, when a group of MIT students were found to have conducted a late night dialling experiment on the Defense Department's secret network. They were rewarded with jobs when they explained their system to Bell investigators. ... The name "phone phreak" identified the enthisiasts with the common underground usage of freak as someone who was cool and used drugs. ["New Scientist," Dec. 13, 1973]The ph- in phone may have suggested the alteration, and this seems to be the original of the 1990s slang fad for substituting ph- for f- (e.g. phat).
The imitation of telephone touch-tone signals by whistling or by using mechanical devices so that free calls may be readily made: and ''phreaking,'' the art of using the telephone for fun but no profit for the company, came into being (1972+)
/freek'ing/ "phone phreak" 1. The art and science of cracking the telephone network so as, for example, to make free long-distance calls.
2. By extension, security-cracking in any other context (especially, but not exclusively, on communications networks).
At one time phreaking was a semi-respectable activity among hackers; there was a gentleman's agreement that phreaking as an intellectual game and a form of exploration was OK, but serious theft of services was taboo. There was significant crossover between the hacker community and the hard-core phone phreaks who ran semi-underground networks of their own through such media as the legendary "TAP Newsletter".
This ethos began to break down in the mid-1980s as wider dissemination of the techniques put them in the hands of less responsible phreaks. Around the same time, changes in the phone network made old-style technical ingenuity less effective as a way of hacking it, so phreaking came to depend more on overtly criminal acts such as stealing phone-card numbers.
The crimes and punishments of gangs like the "414 group" turned that game very ugly. A few old-time hackers still phreak casually just to keep their hand in, but most these days have hardly even heard of "blue boxes" or any of the other paraphernalia of the great phreaks of yore.