Hello my friend. I have some issues with this machine. I am trying to configure RS232 communication with HIEPPHAT MICRO DNC. I connected only three pins(Tx,Rx,GND) to CN6 port on JANCD MB21 main board but when I tried to send program or receive parameters from CNC it didn't work anyway. Can you take a photo on your main board connections or help me anyway. Maybe I wrongly connected something to the main board. Thank you in advance.