Echo when using LE910

7 thoughts on “Echo when using LE910

  1. We are testing a voice call using the LE910-NAG mini PCIE. The LE910 module is installed in our device that performs a hands-free voice call.

    We hear an echo on the cell phone side when calling the LE910 module using a cell phone. Other than that the audio sounds good (ie. loud and clear) on both ends.

    We send the LE910 module the following command to configure the modem before making the voice call:
    AT#ADSPC=1,1

    I have 2 questions:
    1) Any thoughts on how we can avoid this echo?
    2) According to the LE9x0 AT Command reference manual, the command AT#ADSPC=1,1 enables ECNS. I haven’t found any reference to what ‘ECNS’ means anywhere on the Telit website or anywhere on the internet for that matter. We’re guessing ECNS means ‘Echo Cancellation Noise Suppression’ but that’s just a guess. What does ECNS actually mean? ‘ECNS’ should probably be added to the ‘4 List of acronyms’ section of the AT Command Reference Guide.

    Thank you!

    1. Hello again. It turns out that we were getting an echo because I installed the LE910-NAG mini PCIE on an old version of our hardware. When using a new version of our hardware the command ‘AT#ADSPC=1,1’ was all that was required to eliminate echo. The new hardware has a better microphone enclosure.

      Anyways I have another question. We find that the audio output by our device is not very loud compared to other modems installed in our device. Is there a command that can increase the output of the LE910 module? The command ‘AT#PCMRXG=1200’ does increase the audio output a little but not by very much. Another strange thing is that the command AT#PCMRXG=-5000′ makes the audio output more quiet, but only by a little. It does not mute the audio output as suggested in the AT Command reference manual. We are still using LE910 to make a hands-free voice call.

      Any help appreciated!

    2. Hello again. It turns out that we were getting an echo because I installed the LE910-NAG mini PCIE on an old version of our hardware. When using a new version of our hardware the command ‘AT#ADSPC=1,1’ was all that was required to eliminate echo. The new hardware has a better microphone enclosure.

      Anyways I have another question. We find that the audio output by our device is not very loud compared to other modems installed in our device. Is there a command that can increase the output of the LE910 module? The command ‘AT#PCMRXG=1200’ does increase the audio output a little but not by very much. Another strange thing is that the command AT#PCMRXG=-5000′ makes the audio output more quiet, but only by a little. It does not mute the audio output as suggested in the AT Command reference manual. We are still using LE910 to make a hands-free voice call.

      Any help appreciated!

      1. We tried to reproduce the issue with LE910-EUG  and we didn’t see the issue using EVK and External Codec MAX9867.

        We send these commands to the modem:

        at#adspc?

        #ADSPC: 1,1    Handfree /echo cancellation EN

        OK

        AT#DVICFG?

        #DVICFG: 1,1,2,1,2

        OK

        AT#DVI?

        #DVI: 1,2,1

        OK

        AT#I2CWR=2,1,30,4,19

        > 0010900004000000300000000B0B3414C00000

        OK

        AT#I2CWR=2,1,30,4,17,1

        8a;

        OK

        at#pcmrxg?

        #PCMRXG: 0    >>>at command in DG

        OK

        After implemented these commands we got good performance

        It seems that the problem is in your external codec

        -Please try to change the volume of your external codec

        -for mute to speaker please use with AT#SPKMUT command

        1. Thanks for the feedback!

          Are there any other commands that increase the gain of the LE910 received audio besides at#pcmrxg? We are using LE910 to make a hands-free voice call.

          Thanks again!

          1. A little more information:

            We found the following 2 commands increase the audio received from LE910:

            AT#ADSPC=4,1 (this is louder than ADSPC=1,1)

            AT#PCMRXG=1200

            Even with these 2 commands we fear the audio will not be loud enough when a handsfree voice call is made in a loud environment. We verified that our external codec is configured to maximize the audio received from LE910.

          2. Hi

            Does not exist other commands that increase the gain of the LE910 received audio,only at#pcmrxg

            The command ‘AT#PCMRXG=-1200’ does increase the audio output MIN . 

             the command ‘AT#PCMRXG=5000’ MAX

             Please try increase the gain  in your external codec.

            Also,please find attached LE910/LE920  DVI  interfece appliction note.