public function pulse($pin = 0, $on_ms = 120, $off_ms = 240)
{
self::validateInteger($pin, 0, 1, __FUNCTION__);
self::validateInteger($on_ms, 1, 511, __FUNCTION__);
self::validateInteger($off_ms, 1, 511, __FUNCTION__);
$this->connector->write(self::ESC . "p" . chr($pin + 48) . chr($on_ms / 2) . chr($off_ms / 2));
}