please can you explain further. the Stamp code is designed to echo a response at the same time as carrying out the action. If you read an input eg I1 you will get the pin status.
I think you need to add some more indicators to your code and have a careful look at exactly what is going on. I am sure it will become clear if you examine the strings sent between labview and the stamp, and look at the code which generates the strings.
Best of luck,
Michael.
