Patent ID: 7142825

Claim:
In a radio system including a transceiver designed to operate via a digital data bus with a single control head only, a method for modifying said radio system to enable a selected one of a plurality of control heads to operate said transceiver, each said control head periodically generating an interrupt request signal, comprising the steps of: connecting an interface module between said transceiver and said plurality of control heads; detecting in said interface module when one said control head has generated an interrupt request; causing said interface module to selectively enable the control head that generated said interrupt request to operate said transceiver, wherein the method is implemented using two control heads, comprising the steps of: processing said interrupt request; designating said requesting control head as the active control head and the other control head as the inactive control head; forwarding said interrupt request to said transceiver; receiving a message from said transceiver; forwarding said transceiver message to said control heads; including the steps of: decoding said transceiver message to determine if said transceiver message is a backlighting control message; and if said transceiver message is a backlighting control message, then forwarding said backlighting control message to said active control head; and forwarding a backlighting no change message to the other of said control heads, such that a backlighting change in said backlighting control message is received only by said active control head; if said transceiver message is not a backlighting message, then forwarding said transceiver message to each of said control heads; receiving data messages from said control heads in response to said transceiver message; and selectively forwarding said received data messages from said active control head to said transceiver, thereby enabling operation of said transceiver by said active control head.