I have this U.S. Robotics Performance Pro modem and my Mandrake 9.0 (kernel 2.4.19-16 mdk) does see it just fine. However, it always puts it on /dev/ttyS4 (COM5) and I need it to be on either /dev/ttyS0 (COM1, IRQ4) or /dev/ttyS1 (COM2, IRQ3). I tried using the control center and linuxconf to change the modem's position. That didn't work. I found this program called setserial which says that it does these sorts of things but it says that it is targeted for 2.2.x kernels so I am leery about using it with my 2.4 kernel. So, what is required to change this modem's settings?

please correct me if i'm wrong but i believe pci irq lines are set by the systems BIOS
the only thing i know to do is shuffle stuff around inside or uninstall unused PCI cards

The system might very well decide to set it up however it wants on bootup. In that case, what I need is some kind of utility to then change the settings so that I can make it be either COM1 or COM2. Or, maybe there is a way to do a device link so that COM1 or COM2 can be redirected to where the modem actually is.