Alas, they are but gone.
Those Mini-DIN-8 RS422 to D
E-9 RS232 adapters from Palm are gone. I got two off Amazon roughly 12 years ago. Can't find any more on ebay. Ugh anyways if you're looking for a generic RS232 adapter, the 3rd one from the bottom of the image on dochilli's post is how the palmOne adapter is wired up, and should work fine. From there, you can get a null modem adapter (they make null modem adapters that look like gender changers), then a regular D
E-9 conventional straight cable and roll out.