Yeah, PBC has to be implemented in the VCD card firmware - it's basically the prototype for the "Title menu" stuff you find on DVDs - there is a menu stored on the disc, and you can just select chapters rather than having to work by track numbers. Some implementations also gave you the ability to select which audio track was used (especially useful for HK releases unless you want English coming out of one speaker and Cantonese out the other). There were also a depressingly large number of discs that had the PBC flag set but had missing or corrupt menus - these were especially fun when combined with players that locked out manual track controls when PBC was enabled and didn't let you turn it off, since basically all you could do was watch the whole disc from the start. Edit: Incidentally, well done for getting those boxes - although the VCD Saturn is fairly easy to find here, the boxes are much less so - probably because a lot of people in HK live in small apartments and tend to throw away packaging as soon as they get the product.
well so there's got to be some kind of difference between the 2 vcd cards bundled with those box variations, whether software or hardware, or both i think we're giving vcd cards more attention than the whole world has given them in the last five years