ucom0: Prolific Technology Inc. USB-Serial Controller, rev 1.10/3.00, addr 2 Version 3 is the new PL2303X chip I think, slightly incompatible. I'm having the same problem on OpenBSD, A new batch of usb to serial converter we bought stopped working :( Apparently there is a patch floating for FreeBSD, I've not tested it: http://gate.intercaf.ru/~lesha/6100/ Cedric