New to redHat Linux 9.0 I am having problems using serial port on my linux box. Maybe u guys can help ..

I want to talk to a Hayes compatible modem that is connected on /dev/ttyS0 (COM1) of my laptop .. I tried Minicom, it failed to initialize the modem even though the setting were 19200 8N1, the settings for this modem ...
Couldn't understand exactly how minicom talks, so I wrote a small program that opens the COM port and gets/sets attributes .. Open succeeded but couldn't get attributes, it failed with error code 5 - Input/Output error.

I looked at the serial port settings for /dev/ttyS0 .. heres what it says
/dev/ttyS0, Line:0, UART:unknown, Port:0x03f8, IRQ:4
Baud_base:115200, close_delay:50, divisor: 0
closing_wait: 3000
Flags: spd_normal_skip_test

I think that my serial port is not properly configured, so I tried to autoconfigure it as follows -
setserial /dev/ttyS0 autoconfigure
It returned back to the prompt very fast but didn't change any settings.

I changed the UART type to 16550A but the behavior is still the same.

I read in a post in another forum that if the machine is a dual boot machine and the card is a true card but not recognised by linux, we will have to install the chip driver or this,. Can anyone explain this more. and from where to get the chip driver. I have no problem when I boot in windows.

I have file rc.serial in /usr/share/doc/setserial-2.17/rc.serial .

Does anyone has any suggestions on how to resolve this problem?

Thanks,
Ruchika