NIC and Modem conflict causing PC to crash.

Posted on 2003-11-16
Last Modified: 2010-04-14
Good day,

i'm currently running W2K on my system.  my problem is that while i can install both my NIC and modem successfully, if i attempt to use them simultaneously, the pc hangs into a still screen.

if i have a ntwk connection running i can't dial up with the modem.
if i have a dial up connection running i can't establish a network connection. hence i can't utilize internet connection sharing or NAT.

NB. i have no IRQ conflicts whatsoever, i've checked and double checked this. (i believe that the OS would have made an issue of this upon installion of either device). also i have had no such problem during a previous install of XP pro.

thnx in advc.
Question by:merovingian
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Accepted Solution

Casca1 earned 25 total points
ID: 9759707
Couple of questions.
1) Is the NIC onboard, or an add-on card?
2) Is the Modem onboard, or an add-on card?
3) If yes to either, have you tried moving the (either) card to a different slot?

Sometimes, in fact mostly, Windows sees both cards as a Network Device, and therefore will allow both devices to co-exist on the same IRQ. This is obviously an issue, but with PCI, you have almost no recourse. The only viable alternative here that doesn't replace one of the devices is to move one. If that doesn't work, you might try to reset the BIOS IRQ handling, that MIGHT fix it, or might make it worse.
In a worst case scenario, you might try an external modem, as you should be able to enable the BIOS to lock the Com port, and then windows SHOULDN'T share that IRQ.
Good Luck!

Author Comment

ID: 9761532
i have tried loading the cards into different pci slots; alternating between the video and sound card slots. (all are extractable expansion cards btw). this along with editing the IRQ setting in safe mode as well as the bios proved futile.

even when i checked in sys properties, no one device was found to be sharing an IRQ with another.

though your idea of using an external modem has crossed my mind, i was hoping to resolve this on a software level rather than start substituting parts.


Expert Comment

ID: 9761583
So you are stating that neither card is using the same IRQ, correct?
How about DMA, I/O and Mem address?
Obviously your system is freezing, and you have narrowed it down to the culprits with the issue.
If it's not an IRQ, it would have to be one of the other settings.
It's also possible that the two devices are just plain incompatible. That is rare, but IS possible.

Expert Comment

ID: 9762438
I believe Casca pretty much covered everything in his first post.  It obviously sounds like a resource conflict.  Almost every time I have ran into resource conflict like this, I have managed to fix it in BIOS, or by doing basically, one of the things Casca mentioned.  Bios is a bit trixy.  =P  Try manually setting the IRQ of that PCI slot to an available one.  If you don't know for SURE which one is completely available... go, say, disable all of your serial ports and parallel ports, or something.  Just free one up and use it instead, and see if it works.  If that doesn't... see if XP will let you manually assign memory addresses for that devices resources.  Not all devices do, but if you can, change any and all reasonable settings to another option.  I hope you figure this one out.  =)  I'm rooting for you.  Play with BIOS a bit... you won't kill anything, just possibly have to reinstall XP.  =P  But yeah, go play with BIOS a bunch... try loading the defaults of BIOS, then booting XP and see if that works... if not, try going through and disabling everything you don't need, then booting xp and trying.  Try everything... I don't believe that those two are incompatible.  I hate believing that.  It IS possible... but I hate believing that.  =P

Oh... and although you never had this problem with a previous install... you may have upgraded your BIOS, or may have reset your BIOS, and before you may have had some settings different, so XP handled and set them up differently.  It is rare that XP deals with everything in your computer the same in two different installs.  Especially when there is a few months between them, and random settings different in BIOS, sometimes a single piece of hardware being added/removed.  =P

Ah well... hope you figure this one out... best wishes

 - Insolence
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Expert Comment

ID: 10046416
Haven't heard from author in over two weeks, don't know the status of his problem or if he fixed it already.  Myself and Casca offered some good suggestions and we haven't heard back from the author.

Merovingian: Any word on wether you got it working?  =P  If you did, post it up here what it was, so it can be added to the knowledgebase and close, split, or refund the question.  Take care.

 - I

Author Comment

ID: 10047788
my apologies for my late response.

i tried and double checked both solutions, and eventually i was forced to invest in a new external modem, and work it via the com port - as per casca1's suggestion.

i would like to thank you both tho for your prompt responses and thoroughness in you explainations.


Expert Comment

ID: 10048243
Thanks for the points and score.

Expert Comment

ID: 10051018
No problem.  You're welcome.  =)

 - I

Expert Comment

ID: 10052498
Ditto... Sorry, I didn't see your post, merovingian... New Jobs are a hassle, but so much better than the alternative! 8-)


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