SELECTIVE SIGNALING SYSTEM

摘要

A multilocation private line selective signaling system is arranged to generate privacy lockout tones when a first station at any location goes off-hook. The first such off-hook station is designated a controlling station and circuitry at each location responds to the lockout tones by removing signaling and communicating capability from all but the controlling station. Communication capability is extended only to those stations signaled by the controlling station and busy tone is returned to any off-hook station which has not been given such capability. Each location is arranged with circuitry for controlling data transmission between stations and for preventing any station from interfering with the data.