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RS-422 or 4-Wire RS-485 working model with termination resistor:
2-Wire RS-485 working model with termination resistor:
SUNIX M.2 PCI Express RS-422/485 Serial board equips independent TX and
RX termination resistors for each serial COM port. User can modify the dip
switch setting to avoid impedance mismatched problem when operate under
Multi-drop transmission. Resistors should be added near the receiving side.
Note: Termination resistor near the receiving side.
Manufacturer default jumper setting is OPEN (disable 120ohms termination
resistors across the two wires)
Please refer to the following table to enable or disable 120ohms termination
resistor for each COM (RS-422/485) port. Each COM port is controlled by a
pair of DIP Switch.
SUNIX Host Card
Device
D + (Tx+)
D
– (TX-)
D +
D
–
SUNIX Host Card
Device
Tx +
Tx
–
Rx +
Rx
–
Rx +
Rx
–
Tx +
Tx
–
