*NOTE: In “422” mode, the ECHO setting is not used.

*The Echo mode is useful for detecting if there is data collision occurring on RS-485. If the echoed data is not equal to the transmitted data, then data collision is occurring.

DB9 Pin Assignment

DB9 Pin

RS-422

RS-485

 

 

 

1

TxD -

Data +

 

 

 

2

TxD +

Data -

 

 

 

3

RxD +

NC

 

 

 

4

RxD -

NC

 

 

 

5

GND

GND

 

 

 

6

NC

NC

 

 

 

7

NC

NC

 

 

 

8

NC

NC

 

 

 

9

NC

NC

 

 

 

4

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StarTech.com ICUSB422 instruction manual DB9 Pin Assignment, DB9 Pin RS-422 RS-485