Installing PCI modem in machine with 4 serial ports (HELP!)

[Philip Hallstrom]

Hi -
	I've got a little computer that has four serial ports built-in to
the motherboard.  I want to add a PCI modem (USR 5610B) and am having a
devil of a time.  I know this modem works since I've used it (well,
another one just like it) in another machine no problem.

Here's the computer's board:
http://www.orbitmicro.com/products/embedded%20boards/via/EBC-569.htm

The last time I did this it just worked.  However, this bit from the
Handbook has me concerned:

-----------------------------------------------------------------------
These are the four serial ports referred to as COM1 through COM4 in the
MS-DOS/Windows world.

    Note: If you have an internal modem on COM4 and a serial port at COM2,
you will have to change the IRQ of the modem to 2 (for obscure technical
reasons, IRQ2 = IRQ 9) in order to access it from FreeBSD. If you have a
multiport serial card, check the manual page for sio(4) for more
information on the proper values for these lines. Some video cards
(notably those based on S3 chips) use IO addresses in the form of 0x*2e8,
and since many cheap serial cards do not fully decode the 16-bit IO
address space, they clash with these cards making the COM4 port
practically unavailable.

    Each serial port is required to have a unique IRQ (unless you are
using one of the multiport cards where shared interrupts are supported),
so the default IRQs for COM3 and COM4 cannot be used.
-----------------------------------------------------------------------

I rarely use modems, and am even less proficient at messing around with
IRQ stuff.  What I'm concerned about is that it seems to say you can only
have 4 serial ports (COM1 -> COM4) total... which means I'm kind of
screwed.

I've tried disabling all of the serial ports via the BIOS, but it doesn't
help...

If anyone out there has any light to shed on how to get this working I'd
appreciate it.

Thanks!

-philip