Modem problems

My PCI modem doesnt work in dos.

I see the following in my modem properties.

The interrupt resource ( IRQ ) assigned to this modem may not match the interrupt that DOS applications should be configured to use. The correct settings for DOSapplications using this modem are shown below.
No changes are required to the modem hardware settings, it is already correctly installed. This note only refers to configuring DOS applications that use this modem.No changes are required to the modem hardware settings, it is already correctly installed. This note only refers to configuring DOS applications that use this modem.

the enable dos support check box is grayed out. How do I enable dos support?