The present invention is directed to a display package that, in one embodiment, comprises a plurality of packs containing one or more products and a sleeve. The transmission node includes a bit pattern processing unit for processing a bit pattern of transmitted data to stabilize optical power of a frame signal light to be monitored and a frame signal light producing unit for producing frame signal light to be transmitted on the basis of the bit pattern processed by the bit pattern processing unit. Also, the system includes output means for generating messages to the user relating to the status of the control system in general and to the status of devices connected thereto.