protected function isBinary()
    {
        $binary = false;

        if (($this->dcs & 200) === 0) {
            $binary = (($this->dcs & 4) > 0);
        } elseif (($this->dcs & 248) === 240) {
            $binary = (($this->dcs & 4) > 0);
        }

        return $binary;
    }