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On vehicle models from the E65 on, BMW is for the first time using fibre-optic cables as standard for communication between control units.The optical buses are notable for their high data transmission rate and they are not susceptible to electromagnetic interference. The optical buses in question are the most bus, primarily used for in-car entertainment electronics, and the byteflight bus, which serves predominatly safety-critical functions. http://www.comeinchina.com/bmw-ops-p-5.html