... It can supply optic-electrical isolation only obtain power from RS-232 port, It is high delicacy, function ... RX, GNDRS-485 signalD+, D-, GNDWorking formatAsynchronism, point to point or multi point, 2 wire half-duplexDirectionAutomatic send data ... Working temperature-40 to 80Storage temperature-40 to 85Humidity Relative humidity 5% to 95%Power Input poweredNo power supply needed, powered from TXD, RTS ...