Simultaneous transmitter operation in a radio network is prevented by monitoring the signal received at the control position from the transmitter of the apparatus, this signal being delayed by the passage down land lines connecting the control position to its transmission antenna and the receiver to...http://www.google.com/patents/US5566359?utm_source=gb-gplus-sharePatent US5566359 - Prevention of simultaneous transmitter operation in a ground radio transmitting and receiving apparatus
