Avalue ECM-QM77 - Manual (Page 11)

ECM-QM77 Quick Installation Guide
ECM-QM77 Quick Installation Guide 11
2.3.7 System fan connector (SYS_FAN1)
Signal PIN
GND 1
+12V 2
SYSFANIN 3
SYSFANOUT 4
2.3.8 COM 1 RS-422-485 mode (J422/1)
Signal PIN PIN Signal
485_422TX- 2 1 422RX-
485_422TX+ 4 3 422RX+
+5V 6 5 GND
Note:
J422/485 is available after modify the mode of COM1
in BIOS setting