Do you happen to be running on a multi-core PC with Windows XP?
There's a recurring theme of problems with com ports (especially with USB - rs-232 converters) hanging up on multi-core systems.
N.I. denies it has anything to do with CVI, but we've found that defeating the multi-core or multi-CPU in the PC BIOS or the XP control panel solves the problem. N.I. did finally tell me that the rs-232 library assigns separate threads to the input and output queues, if they exist. You've defeated the output queue and the problem went away - if you're running a multi-core CPU I'll give you $20 to constrain the PC to a single core, enable the output queue, and tell me if it still works
🙂menchar
