A system for reducing an apparent height of a board system is provided. Adjacent to the cover cap toward the hinge member is a movable hinge cap which is coupled to the hinge member and covers the hinged joint, while it is guided on the securing member and the cover cap, respectively, in a manner that it is able to swivel and is movable in longitudinal direction. The resultant signal from the arbitration circuit tells the system which controller to obey. The upper III-V compound layer having the first type doping, and the lower III-V compound layer is at least one of undoped, unintentionally doped having a second type doping, or doped having the second type doping.