This paper introduces an automatic controlled system for interoperability between different twoway radio networks that can cancel any third party may exist in interconnections systems .It depends upon the infrastructure and environmental condition of radio networks already exist and directly interest in voice communications by accessing audio through common featured radios accessory sockets. RF CALL signal along with the DC superimposed in audio are the controls of selecting networks connections and the status of the TX radio of the selected network respectively. The control signals are brought to control unit, microcontroller, to form the control center of the system .The first responder can connect directly with the agency concerned without need to be directed.