Rs-422/485 Interface (Uno-2173Af); Rs-422/485 Selection; Automatic Data Flow Control Function For Rs-485 - Advantech UNO 2173A/AF User Manual

2.3 RS-422/485 Interface (UNO-2173AF)

The UNO-2173AF offers one RS-422/485 serial communication interface
ports: COM3. Please refer to Appendix A.4 for their pin assignments. The
default setting of COM3 is RS-422.

2.3.1 RS-422/485 Selection

The mode of UNO-2173AF COM3 can be selected in the BIOS. Please
enter the BIOS setting screen and select the "Integrated Peripherals", then
the follow screen would be shown. In the screen you can configure the
resource and the mode.

2.3.2 Automatic Data Flow Control Function for RS-485

In RS-485 mode, UNO-2173AF automatically detects the direction of
incoming data and switches its transmission direction accordingly. So no
handshaking signal (e.g. RTS signal) is necessary. This lets you conve-
niently build an RS-485 network with just two wires. More importantly,
application software previously written for half duplex RS-232 environ-
ments can be maintained without modification.
11 Chapter 2