仪表设备的485口定义如下： 1 Shield Shield / operational ground 2 - 3 A RS485 connection pin A 4 RTS Directions control RTS (TTL level) 5 GND1 Ground to VCC1 6 VCC1 Supply voltage +5V DC (max. 100 mA, supply voltage for terminating resistors) 7 - 8 B RS485 connection pin B 9 - 与CS1W-SCB41的485口（两线制）怎样接线？请回答一下，好吗？