National Instruments NI-9862 Getting Started page 6

The NI-9862 features software-selectable bus termination for High-Speed CAN
transceivers. On the NI-9862, you can enable 120 Ω termination resistors between
CAN_H and CAN_L through an API call. The Termination Resistor Specification
table lists recommended termination resistor values.
Figure 1. NI-9862 Pinout
Pin Signal
1 No Connection (NC)
2 CAN_L
3 COM
4 NC
5 SHLD
6 COM
7 CAN_H
8 NC
9 V
SUP
Table 1. Pin Assignments for the NI-9862
CAN Bus Topology and Termination
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 known as a "stub." The pair of signal wires, CAN_H and CAN_L,
constitutes a transmission line. If the transmission line is not terminated, each
signal change on the bus causes reflections that may cause communication errors.
Because the CAN bus is bidirectional, both ends of the cable must be terminated.
However, this requirement does not mean that every node on the bus should have
a termination resistor; only the two nodes at the far end of the cable should have
termination resistors.
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NI-9862 Getting Started