Abstract: A printed circuit card and card edge connector for use with a 32-bit bus include respectively a pattern of conductive fingers and pins in the connector that render the card electrically compatible with existing 8-bit STD connectors and that render the card edge connector electrically compatible with existing 8-bit STD cards. the latter compatibility makes it possible to use in 32-bit systems any of the more than a thousand existing 8-bit circuits without modification; while the former compatibility makes available to 8-bit systems an easy path to growth and the expanded computational power of a 32-bit system.