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From: swh@hpcupt1.HP.COM (Steve Harrold)
Newsgroups: comp.sys.ibm.pc
Subject: Re: VGA versus Ethernet versus IBM PC/AT
Message-ID: <-286529972@hpcupt1.HP.COM>
Date: 29 Nov 89 16:07:23 GMT
References: <1159@cernvax.UUCP>
Organization: Hewlett Packard, Cupertino
Lines: 21

Re : LAN cards in your PC

An experience I had installing a LAN card into my PC may supply you with
a clue.

The PC, an HP Vectra RS/25C (25 MHz, 386), had two serial and two parallel
ports.  Upon installing the LAN card, it (the LAN card) failed to operate.  
When I yanked the serial/parallel card (eliminating COM2 and LPT2), the 
LAN card worked properly.

Then I did some remedial RTFM work and discovered that the LAN card, 
although configurable with respect to IRQ number, only allowed you to select
from the collection assigned to COM1, COM2, LPT1, LPT2!  This means I had
erroneously selected an IRQ that was already in use.

I solved my particular problem by re-installing the serial/parallel card, 
but disabled the LPT2 port.  This permitted me to configure the LAN card
with the IRQ normally assigned to that port.  They lived happily ever after.

Getting back to YOUR situation.  Are you inadvertently re-using an in-use
IRQ number?