A form of hacking, as applied to telephone networks. Phone phreaks exploit weaknesses in the phone system to make long-distance calls for free, tap into other's calls, take control of lines, get free phone services, and the like.
Phreaks (or phreakers) are usually motivated more by technical curiosity and the hacker ethos than any criminal intent (although phreaking is most certainly illegal). To bounce a call through a dozen different switching systems
around the world, to your friend next door - all for free - is regarded by phreaks as an
accomplishment. The fact that they are committing fraud and felonies in the process is regarded as incidental - or perhaps part of the fun.
The tools of phreaking often take the form of "boxes", such as the blue box, red box, or beige box. These devices - whose names refer to their function, not their actual color - generate various useful audio frequencies or
electrical signals. The "red box", which allows you to make free calls from pay phones, is the easiest to build and can be assembled
using two parts from Radio Shack that cost less than ten dollars.
The archetypal phone phreak is John Draper, aka
Captain Crunch, who began phreaking on the West Coast in the 1960s.
The practice of phreaking has declined in recent years, as phone networks have been upgraded from old analog systems to newer, less vulnerable digital systems.