public function getModel(): string
    {
        if ($this->model === null) {
            $parser = $this->getXml("/xml/device_description.xml");

            if ($device = $parser->getTag("device")) {
                $this->model = (string) $device->getTag("modelNumber");
            }

            if (!is_string($this->model) || strlen($this->model) === 0) {
                $this->model = "UNKNOWN";
            }

            $this->logger->debug("{$this->ip} model: {$this->model}");
        }

        return $this->model;
    }