My Serial is not being detected by Kppp. It is an Microlink 56K Internet Modem pluged in to serial port 1. I made sure the port was turn on in my Bios. I tried setserial /dev/ttyS0 port=0x3f8 irq=4 autoconfig. This didn't help. When typed cat /proc/interrupts it did not show the interrupts 4 or 3 in use. However, dmesg | grep tty shows ttyS00 at 0x03f8 (irq=4) is a 16550A and ttyS01 at 0x02f8 (irq=3) is a 16550A and there are two strange entries before that.
computersci4@juno.com

Are you sure it's a "proper" modem, and not just a software "winmodem"? A lot of so-called modems made in recent years aren't actually conventional modems, they are just an interface to the phone line and they require drivers and software to generate the tones required to dial a number and all the modem-type operations required. Older modems would do this all in hardware but it is rare to find modems like these nowadays.

it is an external modem the plugs into the serial ports at the back of the computer. It was made by elsa which no longer produces modems. I bought from a friend used who had no problem or need of drivers of it on an older version of linux, but he was using mandrake. I was wondering if it were a serial port driver problem with my motherboard. You see the the computer i am running fc5 is an older computer with a k7asa motherboard and an old 751/756 amd chip set. The processor is old slot amd thunderbird. I disabled the modem on the motherboard because it was a winmodem which was struck by lightning and wouldn't disconnect from the phoneline. That is why i bought this external Microlink 56k internet modem from my friend. I tested the modem in windows and it worked. If plugged into the usb port and not the serial port I would be more likely to think my friend was full of it. The fact remains few software external modems which plug into a serial port were ever produced. If this modem falls in that handful elsa no longer supports it and i don't know who will.

kppp has a set of diagnostics. If you set the configuration in kppp to /dev/ttyS0 and then run the diagnostic what happens? Nasty things happen to serial ports (even via a winmodem which also uses the serial port) when they are struck by lightening.
Make sure that you as a user are included in the group to use the modem.
If this fails then with the modem connected and powered up do as root;
date > /dev/ttyS0
You should see lights flicker. If not there is a hardware problem somewhere. Check your /var/log/dmesg and look for the lines dealing with ttyS0.

Also try running which allows you to "talk" to the modem - try issuing commands like AT&0 and see if you get a response. That would at least whether you're able to communicate with the modem, and whether it's functioning at some level.