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.