setserial Version 2.17 (27-Jan-2000)

Setserial is a program which allows you to look at and change various
attributes of a serial device, including its port, its IRQ, and other
serial port options.

Starting with Linux 0.99 pl10, only the COM1-4 ports are configured,
using the default IRQ of 4 and 3.  So, if you have any other serial
ports provided by other boards (such as an AST Fourport), or if COM3-4
have been a non-standard IRQ so that you can use time simultaneously
with COM1-2, you *must* use this program in order to configure those
serial ports.

The simplest way to configure the serial ports is to copy the provided
rc.serial file to the appropriate /etc/rc.d directory.  For example,
to install rc.serial on a RedHat system, copy rc.serial to 
/etc/rc.d/init.d/serial, and then run the command "chkconfig -add serial".