The systems, methods, and computer program products described herein are generally configured to monitor actions in digital channels. The light fixture includes a surge protection device with a monitor that indicates when surge protection fails. Openings are provided in the outer surface of the vacuum drum, and a suction source is connected to those openings so that dust, dirt and the like on the surface of the paper substrate are drawn away by the suction as the paper substrate moves along the path of travel over the drum. To this end, the invention provides a curling element in accordance with claim no. Subsequently, a user confirms that the current RF channel is set as the target RF channel by pressing the button. The response of coding and decoding the synchronization data is transferred to corresponding end-user applications.