function unicode_to_textstring($str){
$rawstr = pack('H*', $str);
$newstr = iconv('UTF-16BE', 'UTF-8', $rawstr);
return $newstr;
}
$msg = '67714eac99c500200054006f006b0079006f002000530074006100740069006f006e003a0020';
echo unicode_to_textstring($str);