FYI, running a forum search on "ttl parallel" will turn up a healthy portion of discussion on this. I can mention here though that one unresolved issue remains that port addresses greater than 32768 (decimal, or 8000 hex) may not work. On-board parallel port addresses (e.g., as opposed to OS-assigned add-on card addresses) tend to stay much lower than these max values and so that is usually a fix if this is the issue. But then again, if you had an on-board parallel port (i.e., directly built into your system/mother board) you probably wouldn't be reading this. Sigh. In any case, for v2010, we should have it worked out such that all port addresses work fine--to infinity and beyond.