The interconnection PCB has all of the necessary resistors fitted for the LEDs as well as the diodes needed to enable a Push-to-Test button if required, which would illuminate all annunciators at once. The PCB is fitted with a multi-pin header on the rear for connecting to whichever controller you wish to use. All of the Anodes are connected to +12 volts and the controller pulls the Cathode (via a resistor) down to ground.
Please note that there is no controller included with this panel.