Conference call circuit for use in a key telephone system

摘要

A circuit means is disclosed for use in a key telephone system permitting the connection of a key telephone set to a plurality of central office or PBX line circuit means through the key telephone set and without making a direct parallel connection between the central office or PBX line circuit means. Means are also disclosed permitting the connection, and disconnection of the central office or PBX line circuit means to the key telephone set without requiring the connection and disconnection of the line circuit means by the central office or PBX.