RS232 GND pin
I own an Axon S215.
I want to use the RS232 interface with a 12V RFID reader.
How should I use the "GND" pin for RS232 on the Axon ? Do I need to use it ?
I use another reader (12V as well) with the RS485 interface, but this one has no "GND" pin.
the RS485 and RS232 are completely different buses.
The RS485 is differential and doesn't need the GND, since the logic levels are based on the voltage difference between A and B terminal
The RS232 is not differential and the TX / RX logic levels are based on the voltages between TX and GND and RX and GND.