Using USB-to-Serial Converters in LabVIEW Real-Time

Updated Nov 30, 2023

Reported In


  • USB-232
  • PXI Serial Interface Module
  • C Series Serial Interface Module
  • Serial Interface Device


  • LabVIEW Real-Time Module


  • NI-Serial

Operating System

  • NI Linux Real-Time
  • PharLap
  • VxWorks

Issue Details

I want to use an NI or 3rd-party USB-to-Serial Converter, such as the NI USB-232/4, to do serial communication on my Real-Time Operating System. How do I do this?


To do Real-Time serial communication, it is recommended to use an on-board serial port or use an NI PXI /C Series Serial Interface Module to add serial support to your device.

NI USB-to-Serial Converters converters are not supported as serial interfaces for Real-Time Operating Systems and will be identified as a USB RAW device rather than as a serial port. It is still technically possible to use NI-VISA to control USB RAW devices in Real-Time.

It may be possible to install the driver for some 3rd-party USB-to-serial converters and some NI community users have tested some converters successfully. However USB-to-Serial converters from vendors other than NI are not supported and are not guaranteed to work in LabVIEW Real-Time.

Additional Information

NI recommends customers to use the NI USB-to-Serial Converters for Windows Targets as they are fully supported by NI-Serial for Windows Targets.

For a full list of supported serial interfaces under Real-Time Targets check the NI-Serial for LabVIEW Real-Time Readme.