Paul,

I don't have make, model & serial numbers with me (I can get those to
you later), but all three of the USB-RS232 adapters I've used had one
trait in common: the PC would *think* they were working properly, but
without the manufacturer's driver installed (go figure). But with the
driver(s) installed, they always worked flawlessly.

I know one is the aforementioned Keyspan.

2NO