Abstract: Disclosed is an improved voice switching control system for controlling a plurality of voice switches disposed in voice signal transmission channels between at least two stations each including a loudspeaker for receiving voice signals and a microphone for transmitting voice signals. In accordance with the outputs of comparators, each for comparing the output voice signal with the input voice signal of the same station, either one J-K Flip-Flop or a plurality of J-K Flip-Flops control the voice switches in a complementary manner. A new insertion of a voice message into any one of the stations serves to interrupt the voice message which has been transmitted from another station, and the newly inserted voice message will be transmitted to any other station.