A visual system includes one or more units, where each unit is a displaying unit or a video camera, or a combination of both, and each unit has a receiver. The unit has a transmitter which starts transmitting infrequent, short repetitive bursts if no bursts are received by the receiver; and otherwise transmits a delayed short burst synchronized to the infrequent, short repetitive bursts by the transmitter, in order to synchronize all units in the visual system to each other, while the infrequent, short repetitive bursts will not interfere nor will be interfered by the general use of remote controllers for other purposes.