IDP/ARK-2151S/RS-485
From ESS-WIKI
1. Enable RS-485 in BIOS
Advanced -> IT8768 Super IO Configuration -> Serial Port 1 Configuration -> Choose Serial Port Mode [ RS-485 Mode ] -> Auto Flow Control [ Enable ]
Advanced -> IT8768 Super IO Configuration -> Serial Port 2 Configuration -> Choose Serial Port Mode [ RS-485 Mode ] -> Auto Flow Control [ Enable ]