Which S8 Serial Cable Should I Choose For NI-9871?

Updated Nov 21, 2017

Reported In


  • NI-9871

Issue Details

I want to communicate using RS-485 protocol with NI-9871. There are several options available for S8 serial cables on the NI Website.
Which S8 serial cable should I select and what is difference between isolated or non-isolated cables?



For common serial applications, you should select the Non-Isolated S8 Serial Cable.

For Isolated S8 Serial Cables, the shield is connected to the DB-9 side and not connected to the RJ50 side. This causes isolation of the grounds of the two systems, which is typically not needed for serial applications.

For Non-Isolated S8 Serial Cables, the shield are connected on both ends which enables the two systems to share ground levels.


Additional Information

For more information on pinouts of RJ50 and DB9 connectors, please refer to the Serial Quick Reference Guide


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