This has been bugging me for quite a bit, and I'm posting this for behalf of my friend as well.
So, the basics. It's obvious that there's the 1000 single tone, the 1000T dual tone, and the 1003 three tone (and the 2000 and system 7000), but there's been tiny little variant differences I've noticed.
For example, the 1000A/1000B. I think that it stands for single/three phase models, but my knowledge ends there.
My friend is going to see a "1000ATSA2," which we both don't know what it stands for. I think A2 is related to the blower, but I have no clue what the "S" means. If anyone can list off the variants and what they mean, that would be great. Thanks!