Blue box, Phreaking Wiki

A Blue Box is an electronic device that generates "MF" tones, the same tones employed by a telephone operator's dialing console to switch long-distance calls. The Blue Box emerged in the 1960-70s; it allowed users to route their own calls by emulating the in-band signaling mechanism that then controlled switching in long-distance dialing systems. The most typical use of a Blue Box was to place free telephone calls. A related device, the Black Box, enabled one to receive calls which were free to

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