Satellite communication system with improved conference facility

Abstract From the Canadian patent

V.I. ????? No. 3,?42,350-???? October 15, 1974, reaches symbollic communication system in which subscribers are converted in each other by appropriate assignment of two different transmitting frequencies to two parties, each bring assigned a receiving frequency matching ????'s transmitting frequency. When third party (in co??caes: case operator) must communicate with both subscribers prior art requires operator to have as a minimum two receivers whose outputs are mixed to operator headset and two transmitters fed from operator microphone. One pair of operator transmitter and receiver communicates with one subscriber, the other pair communicates with other subscriber; but subscribers can not …