Fiscal printer video with application program

The present invention relates in general to data processing systems, and in particular, to displaying image data generated by a fiscal printer used in retail, point of sale operations. The present invention discloses a method and system for controlling a system display from the processor controlling a fiscal printer. The system display is controlled by generating an overlay image in a storage device along with overlay image selector data. The overlay image selector data is used to control modifying circuits that can substitute or otherwise modify, with overlay image data, all or a portion of the system display image generated by application software. Since the fiscal printer hardware and firmware is not a part of the particular application software running on a point of sale device the control function of the fiscal printer need not require modification of application software or hardware.