User`s manual

BX-PIB0x Embedded Box System
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3.5 COM1-4 (RS-232/422/485, BIOS Selectable)
3.5.1 COM1-4 in RS-232 Mode
Pin Signal Pin Signal
1 DCD, Data Carrier Detect 6 DSR, Data Set Ready
2 RXD, Receive Data 7 RTS, Ready To Send
3 TXD, Transmit Data 8 CTS, Clear To Send
4 DTR, Data Terminal Ready
5 GND, Ground
9 RI, Ring Indicator
3.5.2 COM1-4 in RS-422 Mode
Pin Signal Pin Signal
1 TXD-, Transmit Data 6 NA
2 RXD+, Receive Data 7 NA
3 TXD+, Transmit Data 8 NA
4 RXD-, Receive Data
5 NA
9 NA
3.5.3 COM1-4 in RS-485 Mode
Pin Signal Pin Signal
1 TXD+, Transmit Data 6 NA
2 TXD-, Transmit Data 7 NA
3 NA 8 NA
4 NA
5 NA
9 NA
3.5.4 COM1-4 RS-232/422/485 Mode Selection
To set the COM mode, boot the system into BIOS Setup Utility and select
Advanced > F81866 Super IO configuration. You will see the following
screen.