Brief description: O-bus
WARNING: This page is about a different car, the 2003 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.
The O-bus differs from the P-bus and I-bus in that it is an optical ring bus. Two optical fibres are connected to each control module on the bus; one fibre for incoming data and one for outgoing data. Received messages are converted by each control module from optical signals into electrical signals and then back again into optical signals. The O-bus has a data transfer rate of 25 Mbit/s
In the most basic model of the car, there are only optical cables behind the dashboard between the ICM and EHU. In other car variants, the optical cables are routed to the luggage compartment, which can contain other units.