A system for simultaneously using a video signal to provide a video picture and computer data. At the transmitting end, a video signal is digitized and then modified by substituting digital signals representative of computer data for those representative of video pixels. The modified signal is reconverted to an analog signal and transmitted to a receiver. The receiver displays the video picture corresponding to the modified signal and extracts the computer data so that they may be provided to the computer. The computer can thus be controlled by the computer data as the video picture is being displayed.