Biostar A620MP-E PRO Manual page 22

COM: Serial Port Connector
The motherboard has a serial port header for connecting RS-232 Port.
22 | Chapter 2: Hardware installation
Pin Assignment
1 Carrier detect
2 Received data
3 Transmitted data
4 Data terminal ready
5 Signal ground
6 Data set ready
7 Request to send
8 Clear to send
9 Ring indicator
10 Key