Receive a "1" in the body

sms.php

<?php
if (isset($_REQUEST['Body'])) {
    $body = $_REQUEST['Body'];
} else {
    $body = False;
}

if ($body && $body == "1") {
    $message = "1 is active.";
    // Add additional logic here...
} elseif ($body) {
    $message = "Received something other than 1: ".$body;
} else {
    $message = "Received nothing in the body.";
}
?>
<Response>
<Sms><?php echo $message; ?></Sms>
</Response>