Advantech UNO-3074, User Manual, Page: 22 / 80

UNO-3074 User Manual 14
2.3.4 RS-232/422/485 Selection
COM3 and COM4 support 9-wire RS-232, RS-422 and RS-485 interfaces.
The system detects RS-422 or RS-485 signals automatically in RS-422/
485 mode.
To select between RS-422/485 and RS-232 for COM3, adjust JP4. To
select between RS-422/485 and RS-232 for COM4, adjust JP5.
You can refer to figures below to set the JP4 and JP5.
Jumper setting for RS-422/485 interface: (Default setting).
Figure 2.2: RS-422/485 Jumper Setting
Jumper setting for RS-232 interface:
Figure 2.3: RS-232 Jumper Setting
2.3.5 RS-485 Auto Flow/RS-422 Master/Slave Selection
You can set the “Auto Flow Control” mode of RS-485 or “Master/Slave”
mode of RS-422 by using the SW2 DIP switch for each RS-422/485 port.
(Refer to Figure A.3 for location of SW2).
In RS-485, if the switch is set to “Auto”, the driver automatically senses
the direction of the data flow and switches the direction of transmission.
Then no handshaking is necessary. In RS-422, if DIP switch is set to “On”,
the driver is always enabled, and always in high or low status.
Note: Please refer to Appendix A.2 Figure A.3 for location
of JP4 and JP5 location