if (cfg->rtu.de_pin >= 0)
    {
        ret = uart_set_mode(uart_num, UART_MODE_RS485_HALF_DUPLEX);
        if (ret != ESP_OK)
        {
            ESP_LOGE(TAG, "uart_set_mode(RS485_HALF_DUPLEX) failed: %s", esp_err_to_name(ret));
            return ret;
        }

        ESP_LOGI(TAG, "UART RS485 half-duplex mode enabled (DE pin=%d)", cfg->rtu.de_pin);
    }
    else
    {
        ESP_LOGI(TAG, "UART normal mode enabled (shield auto-direction assumed)");
    }

    if (resp_len > 0U)
        {
            int written = uart_write_bytes(g_rtu_ctx.uart_num,
                                           (const char *)tx_buf,
                                           (uint32_t)resp_len);

            ESP_LOGI(TAG, "UART wrote %d bytes", written);

            if (written < 0)
            {
                ESP_LOGW(TAG, "uart_write_bytes failed");
                continue;
            }

            ESP_ERROR_CHECK(uart_wait_tx_done(g_rtu_ctx.uart_num, pdMS_TO_TICKS(100)));
        }