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.