There are many physical and electrical differences between the bus types. CAN is a single or two wire bus that uses 5V signal levels. It also offers several communication speeds of 40 kb/s to 125 kb/s or 1 Mb/s. LIN is a single wire bus with 12V signal levels and a maximum communication speed of 20 kb/s. FlexRay is a two wire bus system with low voltage signal levels (around 700mV), and a maximum communications speed of 10 Mb/s. This training module will discuss the CAN and LIN buses which are most commonly used in the automotive industry. FlexRay is a new protocol, still in its definition stage, which will be used for the vehicles in the next decade.