A previous SAE 2001 Congress paper, “Multiplex Bus Progression” [1] introduced the idea of categorizing vehicle serial data protocols into additional areas beyond the traditional SAE Class A, B, and C. This paper will expand on that idea, and provide a 2003 update to the Diagnostics, SafetyBus, Mobile Media, and X-by-Wire categories. All existing mainstream vehicular multiplex protocols (approximately 40) are categorized using the SAE convention plus the new groupings. Top contenders will be pointed out along with a discussion of the protocol in the best position to become the industry standard in each category at this time.
