I don't understand how to use usbd_ble_uart example

[helen]

Excuse me:

                     What is the reason for this log，What else do I need to do？

[Amanda Hsieh]

Hi Helen, 

The log comes from 

        // Send data through CDC ACM
        ret_code_t ret = app_usbd_cdc_acm_write(&m_app_cdc_acm,
                                                m_nus_data_array,
                                                length);
        if(ret != NRF_SUCCESS)
        {
            NRF_LOG_INFO("CDC ACM unavailable, data received: %s", m_nus_data_array);
        }

Do you open the serial port as the documentation indicates? In your computer's Device Manager, the development kit is visible as "nRF52 USB CDC Demo (COMx)". LED 3 turns on.

The support staff is reduced during the summer holidays, and you may experience delayed answers.

-Amanda H.