For updates to the ATR20/20 documentation and last-minute product information, visit RS485 Wiring diagram The RS485 Serial port is located on the left corner of the terminal. RS485 is imprinted on the terminal casing. ^A RS485 communication allows up to 32 terminals to be connected to one serial port. An RS232 port on the host PC is used with an RS-232/RS485 converter to complete the connection. ^B RS485 provides good protection from interference over long runs up to 4000 feet. NOTE: When