>Having installed the card, Win95 detected the new ports. All well
>and good, but in use, com3 stops com1 working and com4 stops com2.
>
>It must (surely) be possible to configure the system so that I can
>use at least three of the ports at the same time.

You most likely have interrupt conflicts.

Right-click on My Computer, go to Properties.  Click on the Device Mangler
(oops, Device Manager) tab.  Click the "+" beside Ports (COM & LPT).  In
turn, double click each of the ports and look at the Resources it uses.

My guess is that you see multiple comm ports sharing and IRQ.  This
probably will report as "No Conflicts" in the box at the bottom, even
though they are doubled-up.

My suggestion is to put each port on a unique IRQ.  I prefer to leave COM1
on 4 and COM2 on 3 to retain DOS compatibility with these ports (COM2 is my
mouse), then put COM3 on IRQ 7 (usually assigned to LPT1 but actually not
used) and COM4 on IRQ 5 (normally LPT2 or mouse).  This is, actually, how
my system is configured.  Must work - I sent this e-mail to you!

If, like me, you have your system maxed out with IDE controllers, sound
cards, NIC, etc then it might not be possible to have everything unique.
In that case, set priorities for yourself.  You might have to disable some
of the sound card, or you can still double-up some of the COM IRQs.

NOTE:  If you are using an external drive (Zip, parallel-to-SCSI, etc.) you
probably need to use the LPT IRQ as it was originally assigned.  In that
case, you might have to go to the second interrupt controller (IRQ's 8 and
above) for your comm ports.  If you have a card that had an IDE controller
on it but won't give you IRQ 10 (etc) for the comm ports, you can always
configure jumpers to use IRQ 5 or 7 or whatever and then cut & jumper it to
IRQ 10 or 11 or whatever.  I did that already also, and it does work.  If
you need the edge connector pinout, let me know PRIVATE and I'll send it
when I can.

Andy

==================================================================
Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865
          Hardware & Software for Industry & R/C Hobbies
        "Go fast, turn right, and keep the wet side down!"
==================================================================