Phreaking
jargonhackingISP & telecom
The exploration and manipulation of the telephone network - the craft that preceded computer hacking and named itself with the ph of phone. Its golden age ran on in-band signaling: the network carried its control tones on the same line as the voice, so whoever could produce the tones could command the switch.
A 2600 Hz tone told long-distance trunks the line was idle; a toy whistle from a cereal box happened to produce it, and a blue box automated the rest. The scene's house organ later took the frequency as its name. Phreaking's people, ethics and folklore flowed straight into the computer underground - the first generation of famous hackers were phone phreaks first.
Also known as: phone phreaking, phreak, 2600 hz