Mysterious IRQ 9!

I have a SUN multi I/O card with 4 serial and 3 parallel possible. I am only using it as a 2nd parallel port. My system is heavily laden with peripherials and the card allows IRQs 3, 4, 5, 7, 9, 11, 12, and 15 to be used. I have it set to IRQ 9 and I/O address 3BC (LPT1). This setup works fine. The strange thing is that viewing the IRQs via the control panel/ system does NOT list IRQ 9 at all. In addition, when I look at LPT1's resources it shows the port correctly as 03BC-03BE BUT it does not list any IRQ as being assigned to that port (IRQ 9 was expected)! How come?? I thought that IRQ's had to be assigned to I/O ports. I know that IRQ's can sometimes be shared (but not port addresses). (No other peripheral is assigned with IRQ 9 on the system)

Thanks, Rich
JamminAsked:
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heathprovostConnect With a Mentor Commented:
Windows normally does not use an interrupt for LPT ports.  There is usually no reason (and this has always been the case) for an LPT port to need an interrupt.  This does not mean that the card isnt using IRQ9, the card will still conflict with something else if it is also on IRQ9.  It just means that Windows 95 isnt actually using the interupt.  You generally wont see an interupt used by an LPT port under Windows 95 regardless of what kind of LPT port it is (either an add-on or a built-in).  Hope this clarifies things.

Heath
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JamminAuthor Commented:
Thanks, That clears things up for me.
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johnmalCommented:
IRQ9 is shared with IRQ2. This is where the conflict might be coming from
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JamminAuthor Commented:
What does IRQ2 do??? It usually has "Programmable Interupt" as a designator but what exactly does that mean. I don't seem to be having any conflicts at the moment but if I Knew what was "programming" IRQ2 then I may be able to steer clear of danger.

Thanks, Rich
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