I have an update on this. I used portmon to watch the ports as I connect to them and I see the problem.

Here's a snippet of my test stub:

my $ob = Win32::SerialPort->new("COM5") || die("Couldn't open COM5");
$ob->baudrate(19200);
$ob->parity("none");
$ob->databits(8);
$ob->stopbits(1);
$ob->handshake("none");
$ob->write_settings || die("Couldn't write serial port settings");
[download]

When I run this with COM1 (a motherboard port) portmon reports that it was opened at 19200b, which is what was requested. However, when I run this with COM5 (the add-on card) portmon reports that it was opened at 1200b. Any ideas to why the add-on card would be ignoring the baudrate request?

-Nitrox