A CAN bus consists of two or more CAN nodes cabled together. The CAN_H and CAN_L pins of each node are connected to the main CAN bus cable through a short connection called a stub. The pair of signal wires, CAN_H and CAN_L, constitutes a transmission line. If the transmission line is not terminated, signal changes on the bus cause reflections that can cause communication errors. The CAN bus is bidirectional, and both ends of the cable must be terminated. However, only the two nodes at the far end of the cable, not every node on the bus, require termination resistors.

The following figure shows a simplified diagram of a CAN bus with multiple CAN nodes and proper termination resistor (Rt) locations.

Figure 25. CAN Bus Topology and Termination Resistor Locations