Phreaking is a slang term coined to describe the activity of a subculture of people who study, experiment with, or explore telecommunication systems; such as equipment and systems connected to public telephone networks. As telephone networks have become computerized, phreaking has become closely linked with computer hacking.[1] This is sometimes called the H/P culture (with H standing for hacking and P standing for phreaking).
http://en.wikipedia.org/wiki/Phreaking
