David: Older versions of LabVIEW and NI-VISA had a few issues with async I/O that have been discussed widely in the various forums. If upgrading LabVIEW isn't in the cards for you at this time, there might be a couple of other (free) alternatives to try.
One of them is to obviously increase the read timeout like Josh suggested. Another is to upgrade your NI-VISA, which should be backward compatible to LabVIEW 5.x. A final suggestion is to create a read wrapper VI that calls VISA Read, then if it times out, sees if any more data is available at the port and calls VISA Read again. That last suggestion is a hack, but sometimes hacks are in order. You asked what version of NI-VISA you have. There are a few ways: 1) Manual/best: look at the readme.txt in Start>>Programs>>National Instruments>>VISA, which should say the version right near the top 2) Manual/alternative: right-click on <windows>\system32\visa32.dll and look at the version resource 3) Programmatic: drop a VISA property node and choose Version Information>>Version of Implementation. Treat it as a hex value formatted like MMMmmmss (Major, minor, subminor). In other words, 0x00200601 would be 2.6.1. Dan Mondrik National Instruments
