USB and on-board modems not working together

[areid 0]

I have a Hayes Accura ISDN Modem which I connect to my laptop (XP Pro (SP1)) via. a USB port. Everything works well until I use the on-board 56k modem.

 

When I use the 56k modem (not at the same time as the ISDN modem)

it behaves very erratically, often slowly and often disconnects within a couple of minutes of connecting! If I physically disconnect the ISDN modem from the USB port (after 'safely' disconnecting via the software, otherwise I get the famous BSOD), everything is ok with the 56k modem.

 

I don't want to (and shouldn't have to) remember to unplug my ISDN modem (which is a pain to have to do via the software) every time I use the 56k modem (which is v. frequently).

 

Is there any way that both modems can live in harmony? Any help would be appreciated. I have made sure that the latest modem drivers are installed.

 

TIA,

Alan

[Sampson 0]

Sounds like the classical IRQ sharing problem. Several devices may share the same IRQ and a couple of them are in conflict. Right click on My Computer and bring up the hardware manager and see what devices are sharing the same IRQ's with your 56K modem.

[areid 0]

Sampson, thanks for the reply.

 

>Sounds like the classical IRQ sharing problem.<

 

I think you've got it.

 

The 56k modem uses IRQ10 (I/O range E200-E2FF), and the properties says that there are no conflicts. The USB modem appears in the device list as a network adapter USB ISDN TA, for which no IRQ is listed.

 

However, I discovered in the device manager that under 'USB controllers' is an entry for 'VIA Rev 5 or later USB Universal Host Controller' which also uses IRQ10 (I/O range 12000-121F) (again it says there is no conflict!).

 

This could also explain the fact that there is much cooling-fan activity when the USB modem is plugged-in (I rarely heard the fan until I got this modem!). It seems to me really bad configuration that the internal modem should have the same IRQ as the USB controller!

 

So, now I think we've cracked the problem, how can I change the IRQ for either the 56k modem (preferably) or the USB port?

 

Many thanks,

Alan

[Sampson 0]

Actually, there is not much you can do about it. If this were a desktop, you could try pulling the modem out and putting it into a different slot. That will sometimes allow XP to reassign the IRQ. Since this is a laptop and the modem is built in, that idea won't work. It may be possible that your laptop has a later bios and by flashing it, this could reassign the IRQ or there may be a firmware upgrade on the modem. I think that Hayes is out of business, but there may be a software upgrade that could change the IRQ (though I doubt it.) It is a shame that there is a conflict. Your laptop maker probably never considered that the USB port would be used for another modem. I wish I could give you a solution. If I run across something, I will get back to you.

[areid 0]

Samspon, thanks for the reply.

 

>>I think that Hayes is out of business,<<

Really? They are still selling loads of stuff here in the UK.

 

>>... but there may be a software upgrade that could change the IRQ (though I doubt it.)<<

I'll look into it.

 

>> If I run across something, I will get back to you.<<

Many thanks. I'll contact the laptop manufacturer and see if they have any ideas.

 

Regards,

Alan

[trilliansucks 0]

or you could manage your IRQs from the bios instead of having XP do it.

[areid 0]

trilliansucks, thanks for the reply.

 

>>or you could manage your IRQs from the bios instead of having XP do it.<<

 

I presume managing IRQs from the bios involves looking at the setup when the laptop boots-up, but how can I do it from XP?

 

TIA

Alan

[Sampson 0]

Generally, as the computer boots up, you can hit the Del key or the Esc key (and since it is a laptop you may have a key sequence) before the computer gets into windows. Some laptops simply won't let you get into the Bios. If yours does, then a set of screens comes up. Don't change anything your first go around. Write down the values you find in case you accidentally change something. That's the Bios; that's where you can change IRQ's. With laptops it is probably pretty limited, but it won't hurt to look.

[jmmijo 1]

Here's something else that could help free up some resources here:

 

1) If you don't use a serial mouse then disable both the COM1 and the COM2 ports in the system BIOS.

 

2) If you don't use a parallel printer, then you can also disable the LPT1 port in the system BIOS.

 

This will essentially free up 3 IRQ's for and base addresses for you to use. Hopefully XP then can reassign to the proper, non-shared IRQ's and everything will work.

 

You have d/l the latest device drivers for the onboard modem I presume ?!?