#!/usr/bin/perl --
use strict;
use warnings;
use Pashnoid::Fire;
my @ok_ports = Pashnoid::Fire->get_ports();
...

##</code><code>##

package Pashnoid::Fire;
use Perl::OSType qw' is_os_type ';
if( is_os_type('Windows') ){
    eval q{use parent 'Pashnoid::Fire::Win32'; 1} or die $@;
} else {
    eval q{use parent 'Pashnoid::Fire::Linux'; 1} or die $@;
}
1;

##</code><code>##

use Win32;
...
sub get_ports {
   my( $selfOrClass ) = shift;
...

##</code><code>##

use Device::SerialPort;
...
sub get_ports {
   my( $selfOrClass ) = shift;
...