Abstract: In accordance with the invention, the present disclosure is related to a sign display panel for displaying a sign display panel message. The sign display panel includes at least one set of display units. Each display unit of the at least one set of display units includes a plurality of display units. In addition, each of the plurality of display units includes a display unit central processing unit (CPU) configured to execute software instructions associated with the display of the sign display panel message, a display unit memory configured to store the software instructions for execution by the display unit CPU, and a plurality of display elements configured to respond to signals sent from the display unit CPU. The sign display panel also includes at least one interconnect (IC) unit. The at least one IC unit is coupled to a first display unit and a second display unit included in the at least one set of display units.

Abstract: In accordance with the invention, there is described a sign display panel made up of a controller connected in a serial communication network with a set of display units. Each of the display units receives messages from the controller and detects errors in the messages. The controller sends a series of communication integrity messages to the set of display units. When a display unit receives the communication integrity message, it sends it to the next display unit or back to the controller. If a display unit does not receive a communication integrity message within a set time interval, the display unit sends an error message that is received by the controller.