ICP DAS USA mPAC-7186EXD-CAN User Manual page 16

Moreover, in order to wire conveniently, the I-7188XBD-CAN/
μPAC-7186EXD-CAN provides not only one CAN port, but also another
bypass CAN port. There two CAN ports are the same one. The bypass
CAN port is just for wiring with another CAN device conveniently, it doesn't
have any other function.
120Ω JP 3
I-7188XBD-CAN/μPAC-7186EXD-CAN user manual (ver.1.0.3, May/09/2014) 16