//* ASCII ke Hexadecimal
function ascii2hex($str) {
$result = '';
for($i=0; $i<strlen($str); $i++) {
$hex = strtoupper(dechex(ord($str[$i])));
$hex = str_pad($hex, 2, '0', STR_PAD_LEFT);
$result .= $hex;
}
return $result;
}

//** Hexadecimal ke ASCII
function hex2ascii($str) {
$hex = str_split($str, 2);
$result = '';
foreach($hex as $hex) {
$ascii = chr(hexdec($hex));
$result .= $ascii;
}
return $result;
}