jack in

To log on to a machine or connect to a network or {BBS}, esp. for purposes of entering a {virtual reality} simulation such as a {MUD} or {IRC} (leaving is "jacking out"). This term derives from {cyberpunk} SF, in which it was used for the act of plugging an electrode set into neural sockets in order to interface the brain directly to a virtual reality. It is primarily used by MUD and IRC fans and younger hackers on BBS systems.

---