Avalue EEV-EX03 - Manual (Page 11)

Quick Installation Guide
EEV-EX03 Quick Installation Guide 11
2.3.4 Serial port 2 RS232/422/485 mode select (JP1)
* Default
RS232*
RS422
RS485
2.3.5 Serial port 2 pin 9 signal select (JRI2)
* Default
Ring*
+5V
+12V