Hyperterminal will certainly be helpful to make sure that you are getting valid data. You might also want to try VISA Interactive Control from Measurement and Automation Explorer under Tools...NI-VISA...Interactive Control. You will be able to exactly simulate the calls that are being made in your program such as writing and reading. Additionally, you will be able to see whether or not an error is returned from your read and what the error means. The basic problem here has got to be your stop bits, data bits, baud rate, or parity settings. VISA will not report a parity error unless the lower Windows API drivers do.
Scott B. Applications Engineer National Instruments
