When I said "write them to the serial port", I didn't mean "shove them out through some non-existent pins in a non-existent D-type connector". I meant, "write the data to wherever the kernel will pick it up as data coming in via the serial port if it's possible." I'm probably making a bunch of stupid assumptions in saying that, but if I knew all those answers, I wouldn't be asking the questions, right?

Your idea of linking the two implies that USB and serial ports share exactly the same protocol. I don't know if that's what you meant to imply, but - hell, I can't see any harm in trying it, so I'll give it a shot. At least it's a directions I hadn't thought about before. Thanks - I really appreciate that!