Intel FPC 5084 - Manual (Page 20)

FPC 5084
Hardware Installation 12
When COM1 is set to RS-422 or RS-485, the pin assignments are
listed below:
Pin #
Signal Name
RS-422 RS-485
1 TX- DATA-
2 TX+ DATA+
3 RX+ No connector
4 RX- No connector
5 No connector No connector
6 No connector No connector
7 No connector No connector
8 No connector No connector
9 GND GND