A system to enable a computer to provide output to a display over a general-purpose data transmission medium, such as USB. The system includes provision of a plurality of display interface components, each display interface component adapted to receive display data and transmission of the display data to the display via the general-purpose data transmission medium. Each component is associated with a respective stage of operation of the system. The system is configured to use a respective one of the display interface components during each of a plurality of distinct operational stages.