Sorry, the code block is incorrect and has a close($serial) that was added later when troubleshooting. The code actually looks like this: 
use IO::Select;
use IO::Handle;

$COM_PORT = "COM1";
my $Serial;

#system("mode com1 baud=9600 stop=1 data=8 parity=n rts=on dtr=on");
#open $Serial,"+<", "$COM_PORT" or die "failed to open com port\n";
sysopen $Serial,"$COM_PORT", O_RDWR|O_NDELAY|O_NCOTTY or die "failed t
+o open com port\n";

$sel = IO::Select->new;
$sel -> add($Serial);

if($sel -> exists($Serial))
{
    print "Handle exists \n";
}

print $Serial "\n";

my $timeout = 0;

if (my @ready = $sel -> can_read(0))
{
    print "Ready to read! \n";
}

if (my @ready = $sel -> can_write(0))
{
    print "Ready to write! \n";
}

if(my @ready = $sel -> has_error(0))
{
    print "Exceptions found! \n";
}

close ($Serial);

print "Finished... \n";

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In reply to Re: Serial Port I/O by Anonymous Monk
in thread Serial Port I/O by Anonymous Monk

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