Advantech MIC-3399 User Manual page 53

2.3.3.12 Serial Port 2 Configuration
Serial Port

This item allows users to enable/disable the serial port (COM).
Serial Port2 Mode

This item allows users to set the serial Port2 mode as RS-232, RS-422, RS-485
without term, or RS-485 with term.
Figure 2.26 Serial Port 2 Configuration
41 MIC-3399 User Manual