The CAN bus uses differential signal transmission, and usually only two signal lines (CAN-H and CAN-L) are required for normal communication. In the case of strong interference, it is also necessary to use the shielding ground CAN-G (the main function is to shield the interference signal), and the CAN protocol recommends that users use shielded twisted pair wire as the transmission line of the CAN bus.
In the \"hidden\" state, the input differential voltage of CAN-H and CAN-L is 0V (up to 0.5V), and the common-mode input voltage is 2.5V.