use Win32::SerialPort;
use strict;
use warnings;

$| = 1; #enable autoflush

my $PortName = "COM1";
my $sendData = "12345678";

### SERIAL PORT SETUP ###
my $PortObj = new Win32::SerialPort($PortName) or die "Can't open $PortName: $^E\n";
$PortObj->baudrate(57600);
$PortObj->parity("none");
$PortObj->databits(8);
$PortObj->stopbits(1);
$PortObj->write_settings(); #very important!

$PortObj->write($sendData);

$PortObj->close() || warn "\nClose failed\n";