PHP kirim data Serial

penjelasan singkat yang tidak faham bisa tanyakan salam sukses

<?php
$fp = fopen('COM1','r+');
fwrite($fp, "1"); //write string to serial
fclose($fp);
echo "hidupkan lampu !";
exit();
?>

<?php
$fp = fopen('COM1','r+');
fwrite($fp, "0"); //write string to serial
fclose($fp);
echo "matikan lampu !";
exit();
?>