The present invention is directed to a system and method for providing an interoperable communications system including a plurality of otherwise disjunct communication systems each including at least one communications device. The system includes a plurality of system interface controllers each coupled to one of the communication systems and a common network for connecting the communication system and associated communications devices to the common network. A controller is coupled to each of the system interface controllers. The system interface controller being operable in response to commands from an authorized controller wherein the connection between each of the communication systems and the common network is controlled by a controller associated with, and authorized to control each communication system. The system provides an interoperable communications system between the otherwise disjunct systems wherein the communications devices for each system coupled to the common network are in communication therebetween.