+12V DC Positive. Must be fused at the battery (typically 50A or 60A depending on total load).
The diagram centers around the "Main Control Unit." Radiating outward are connections to the "Sapphire" lightbar, the siren speaker, the control head (the box with buttons inside the cabin), and various peripheral switches. The diagram teaches you that the system is not just a collection of wires; it is a data network. Understanding the difference between the (for lights and sirens) and the Low Current Logic Inputs (for triggers like "air horn" or "gun lock") is the first lesson the diagram offers. cencom gold wiring diagram