Hello adigerimu,
If you are using National Instruments ComponentWorks (Tools for Visual Basic) package, you can find serial examples located at "C:\MeasurementStudio\VB\Samples\Instr\Basic Serial" or wherever you installed Measurement Studio. We also have an example that uses VISA online at http://zone.ni.com then click RESOURCE LIBRARY >> COMPONENTWORKS >> GENERAL and look for links that mention "serial". If you are not using ComponentWorks, then this is not the appropriate newsgroup for your question, and I would recommend you start by looking at http://www.msdn.microsoft.com.
Jeremiah Cox
Applications Engineer
National Instruments
http://www.ni.com/ask
