Abstract: A loudspeaking teleconferencing circuit serving a plurality of remote conference room locations includes a plurality of speakerphone sets at each conference room location and a communication network connected to an incoming and an outgoing terminal at each location. The transmit channel of each set couples a microphone to the outgoing terminal; the receive channel of each set couples the incoming terminal to a loudspeaking device; and a control circuit selectively activates one of the set transmit and receive channels at a time responsive to speech energy present on the transmit and receive channels. Each set control circuit is operative independently of the control circuits of the other sets; and the outputs of all active transmit channels are combined and applied through the location outgoing terminal to the communication network.