Add RS-232 or RS-485 Serial Communications to cDAQ-9188

Updated Apr 17, 2024

Reported In


  • cDAQ-9188
  • NI-9870
  • cDAQ-9137
  • NI-9871

Issue Details

I want to add RS-485 and RS-232 serial communications to a system that uses cDAQ-9188.  The only cDAQ or C Series serial modules that I see are for CAN and LIN.  Is there a way to get RS-485 into a cDAQ module? Or do we need to send it into an open slot on the PC (or convert to USB)? 


No, the cDAQ-9188 does not support RS-232 or RS-485 serial communications on the chassis itself, or through a C Series module.

In order to use serial communications with NI cDAQ you will need one of the following:
  • (RS-232 only) A cDAQ-913x controller, such as the cDAQ-9137, have a RS-232 port on the device. Note: NI no longer sells CompactDAQ Controllers.
  • An NI CompactRIO(cRIO) controller.
    • cRIO controllers are compatible with the NI-9870 , which is a module designed for RS-232 communication.  They are also compatible with the NI-9871, which supports RS-232 and RS-485.

Additional Information

In order for RS-232 or RS-485 communication to be possible the chassis must have NI-VISA installed, and this cannot be installed on a chassis such as the cDAQ-9188.