At 8/15/2001 08:06 PM, David Gordon wrote:

>I have a Digicom Systems DSI v.90 ISA modem.  When I install it, it
>defaults to Comm 4.  There is no Comm 4.

David,

You may be working under a false assumption.  Probably the Digicom is
installing it's own comm port 4.  Your ISA modem has its own comm port on
the card the port may not show up in the ports listing on the Device
Manager.  As long as it gets assigned an IRQ not used by another device and
has the correct I/O address, the comm port on the modem card will work
fine, no matter what the comm port number.  I used to have very old
software that expected the modem to be on either comm 1 or 2 but I've not
seen that in several years.

I have a Zoltrix ISA modem that assigned itself comm 4 and that doesn't
conflict with the comm port on my motherboard which is comm 1.  Comm 1 and
3 share the same IRQ normally and comm 2 and 4 share another.  You *don't*
want the modem to be on a comm port that is physically present and enabled
on your motherboard if you intend to use the MB port.   The only thing that
determines the comm port number is the I/O address that is used.

If you've installed the modem and it doesn't work, the comm port thing may
be a red herring and you need to look elsewhere to find out why it's not
working.  IRQ conflicts are the most common reason a modem doesn't work.

I hope this helps.

Doug

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