Moxa Technologies PCI Express Board User Manual page 73

PCI Express Boards
3. Check the Auto Enumerating COM Number option to map subsequent ports automatically. The port
numbers will be assigned in sequence. Select Interface (RS-232, RS-422, RS-485-2W, or RS-485-4W)
from the drop-down box. An Auto Tuning function is provided with RS-485-2W. Click OK to save the
settings.
4. Click OK on the Ports Configuration page to save the settings.
5. Test if the communication is OK. If it's not OK, proceed to Step 6.
6. Click on the COM Number, and then click Auto Tuning and click OK. The PCIe board will automatically
detect the RS-485 environment and suggest the correct Bias Resistor and Termination Resistor. Click OK to
save the setting. To apply the setting, you need to click OK on the Ports Configuration page.
7. Test if the communication is OK. If it's not OK, proceed to Step 8.
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Intelligent RS-485 Settings