◆ 串行接口 EIA/TIA-232 RS-232 (ITU-T V.28)
EIA/TIA-422 RS-422 (ITU-T V.11)
EIA/TIA-485 RS-485 (ISO/IEC8284)
串口界面:
RS-422: TxD+ TxD- RxD+ RxD-
RS-485 4 wires: TxD+ TxD- RxD+ RxD-
RS-485 2 wires: A(对应Txd+) B(对应Txd-) Signal Ground
RS-232: RXD TXD Signal Ground
物理接口:RJ45