CAN technology has been standardized since 1994 and is described by three ISO documents. ISO 11898-1 describes the CAN protocol. With respect to the reference model for data communication, the CAN protocol covers the data link layer (MAC - Medium access control, LLC - Logical link control) and the physical layer (PLS - Physical signaling). The CAN protocol is implemented in hardware. In the meantime, many CAN controllers have become available.
The two ISO documents ISO 11898-2 and ISO 11898-3 cover the rest of the physical layer of the reference model for data communication (PMA - Physical medium attachment, MDI - Medium dependent interface). They describe two different CAN physical layers: The high-speed CAN and low-speed CAN physical layers. The high-speed CAN physical layer (ISO 11898-2) is implemented by a high-speed CAN transceiver, and the low-speed CAN physical layer (ISO 11898-3) by a low-speed CAN transceiver. High-speed CAN transceivers support data rates of up to 1 MBaud, and low-speed CAN transceivers up to 125 KBaud. High-speed CAN transceivers are generally utilized in the powertrain and chassis areas. Low-speed CAN transceivers are used in the convenience/body area.
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