I was a bit curious about the VISA passport itself as well. I have not been able to see any mention of the Passport compatibility, but judging by the fact that this instrument is usable in environments that are known to use VISA-C, but not in an environment that would make use of VISA-COM, I would have to agree with the post you linked. Unfortunately, I have not documentation or detailed explination for why that is though.
Mathew H.
Applications Engineer
National Instruments
