The Component Works VB control was created before VISA became very popular. That is why it exists at all today.
In order to avoid having multiple NI Serial drivers and APIs, our newer environments (such as the C++ support in Measurement Studio) do not have a separate Serial API. NI-VISA has every bit of the functionality that any OS provides, plus a lot more that is relevant to instrument control (for example, termchar support), so there are no technical limitations that I am aware of.
If you are having any trouble with getting the VISA API to work properly for you, please let us know.
Dan Mondrik
Senior Software Engineer, NI-VISA
National Instruments
