Phreaker
A hacker who specialized in compromising telephone switching systems and long-distance networks, often through social engineering and tone signaling.
Phreaking emerged in the 1970s alongside computing when telephone exchanges still used analog frequency shifts and tone-based signaling. A skilled phreaker could generate the correct tones (often with a synthesizer or a pre-built "blue box") to trick the switchboard into routing calls or granting access to services without payment. Some phreakers were pure electronics hobbyists fascinated by the technology itself; others saw it as a means to free long-distance calls. Many eventually transitioned to computer hacking or security consulting — the phreaking to hacking pipeline produced some of the era's most notable figures.