setserial - 2.17-56 main

Set and/or report the configuration information associated with
a serial port. This information includes what I/O port and which IRQ
a particular serial port is using.
.
This version has a completely new approach to configuration, so if you
have a setup other than the standard ttyS0 and 1, you will have to get
your hands dirty.
.
By default, only COM1-4 are configured by the kernel, using IRQ 3 and 4.
If you have other serial ports (such as an AST Fourport card), or
if you have mapped the IRQs differently (perhaps COM3 and 4 to other
IRQs to allow concurrent access with COM1 and 2) then you must have this
package.