function tis2utf8($tis) {
    for ($i = 0; $i < strlen($tis); $i++) {
        $s = substr($tis, $i, 1);
        $val = ord($s);
        if ($val < 0x80) {
            $utf8 .= $s;
        } elseif (( 0xA1 <= $val and $val <= 0xDA ) or ( 0xDF <= $val and $val <= 0xFB )) {
            $unicode = 0x0E00 + $val - 0xA0;
            $utf8 .= chr(0xE0 | ($unicode >> 12));
            $utf8 .= chr(0x80 | (($unicode >> 6) & 0x3F));
            $utf8 .= chr(0x80 | ($unicode & 0x3F));
        }
    }
    return $utf8;
}

function utf8tis620($string) {
    $str = $string;
    $res = "";
    for ($i = 0; $i < strlen($str); $i++) {
        if (ord($str[$i]) == 224) {
            $unicode = ord($str[$i + 2]) & 0x3F;
            $unicode |= ( ord($str[$i + 1]) & 0x3F) << 6;
            $unicode |= ( ord($str[$i]) & 0x0F) << 12;
            $res .= chr($unicode - 0x0E00 + 0xA0);
            $i += 2;
        } else {
            $res .= $str[$i];
        }
    }
    return $res;
}