Aaeon SBC-357 Manual page 29

If COM2 (CN7) is assigned as RS-422/485, it's a dual-in line box
header connector.
Pin Signal
1 DCD
2 RX
3 TX
4 DTR
5 GND
6 DSR
7 RTS
8 CTS
9 RI
10 NC
11 B485TXD+
12 B485TXD-
13 B422RXD+
14 B422RXD-
Chapter 2 Hardware Configuration 21