I think NI DAQ is the software libraries that allow you to use the cards from C++ programs. However, I could only find it for Windows/Macintosh. I was told that the 6023E card (and some other card that I ordered which does Analog output)would work under Linux. I don't have LabView for Linux or Measurement Studio. All I need is to be able to output a current and read in a current, as well as output on the Digital line. This all needs to be done from a Linux C++ compiler (preferably GNU).