Includes three SPF (Source Power Flag) modules and one SPF power supply. The SPF, source power flag is used in conjunction with the remote control setup/on-off command configurations to keep common sources in sync with system ON/OFF status. The SPF is an active device that can sense the presence of composite video or coaxial digital audio from a common source component. When no signal is detected, the source is OFF and the SPF waits for a change of status. When a composite video or coaxial digital audio signal is detected, the SPF sends a 12V control voltage to an AVR21EN SPF FLAG-IN to let the AVR21EN know the component is ON.