Hello,
It is not very clear what you want to do. For what I understand you have an instrument that you are connecting to a gpib, or serial or tcp port in your computer. Matlab should be able to do the link between VISA and the instrument. Are you using NI-VISA? Are you using LabVIEW or any other software?
If you are using one of our GPIB cards or serial cards, then you would also need the driver for that hardware.
Hope this answers your question. If it doesn�t please provide more description like if you would like to call a Matlab script through LabVIEW or something like that.
Thank you,
Ricardo S.