Modem Question

[Cyber Source]

I have a modem that when probed using linuxconf it comes up as being
detected on /dev/ttyS4 , I have no selection in my internet dialer for
that, it only goes up to /dev/ttyS3. I have disabled and played with the
ports in the BIOS but it does not change. How can I change it to something
lower or to add that high of a device into the internet dialer? Linux
newbie here, try and keep it simple. Thanks, Peter