Abstract: A display control system provided between a computer and a display device includes a plurality of display control LSI's for data transfer and also displays image data stored in a plurality of image memories having planes on the display device by controlling plane groups which include one or more planes. Each display control LSI includes an enable generator for generating a synchronization enabling signal in accordance with LSI designation information and an input/output buffer for outputting a synchronization signal in response to the enabling signal. A synchronization signal from one of the plurality of display control LSI's designated by the LSI designation information is supplied to the plurality of display control LSI's inclusive of the designated display control LSI through a signal line to allow the plurality of display control LSI's to operate with each other, thereby making it possible to produce and display data to be simultaneously on the display device.