Introduction of automobile multiplex communication system

摘要

The great advance in automobile electronics has multiplied amount of wiring harnesses (bundles of wires) to connect Electrical & Electronics (E/E) components. Consequently, there have been problems in packaging, weight, and cost for a long time. As a solution for that, automakers have studied multiplexing system that can transmit plural signals in one wire or two. Multiplexing system was applied to some products by automakers before. We also applied our unique multiplexing communication protocol named "PALMNET" to Cosmo (in 1990) and Sentia (in 1994). However, communication IC in E/E components was expensive. Thus, it was profitable only for high-graded luxury cars with many E/E components because luxury cars were given with merits of reducing wires even with expensive multiplexing system. Since 1998, cost of communication IC has been drastically reducing, it becomes possible to develop standardized multiplexing system applicable to compact car through luxury car. Most automakers started to expand employing of multiplexing system in their products, trying to standardize them. That leads to volume increase of communication IC in the market and further cost reduction. We are now furthering study and evaluation on such new multiplexing system, and communization with Ford, Volvo, and Jaguar aggressively.