RC7620 echo cancellation not working correctly

IoT Modules RC76
1

Hello,

We are using the RC7620 module to make calls. The echo cancellation is working properly because when we deactivate it we see that a very noticeable echo appears.

Our problem is that even with the echo canceller activated the last word pronounced by the receiver of the call is echoed. I do not know if my explanation is sufficiently clear, the steps that we perform are:

  • The source which is an embedded device makes the call to a cell phone.
  • The receiver cell phone answers the call.
  • The conversation starts and when the user with the cell phone speaks, always has the echo of the last word he says. You can have a conversation but you always hear the last word you say.

Our doubts are:

  • Is there any parameter of the echo cancellation algorithm that can be configured using AT command?
  • Is there any way to reduce the echo when you finish speaking?

The modem firmware version is “SWI9X07H_00.08.24.02 f90cbd jenkins 2022/03/21 03:47:54”.

2

Hi @gplaza,

Welcome to our community!

  1. Please update to the latest firmware to see if the issue still occurs.
  2. Is the issue currently observed on multiple RC7620 modules or just one? If just one, could you please recheck on another RC7620 module?
  3. Are you using RC7620 with Sierra board or customer board? If it is possible, please help recheck on Sierra board whether the problem is resolved.
  4. If the issue still occurs, please share AT command log you did.

Thanks,

3

Hi @jerdung

  1. We have updated the firmware version to “SWI9X07H_00.08.44.07 2539f0 jenkins 2023/04/26 10:17:51” but the issue still occurs…
  2. The issue has been observed in all RC7620 modules.
  3. Sierra’s evaluation board is not available for us. We will try to get one for testing.
  4. We are not sending any special AT command.

Regards,
Gustavo.

4

Hi @gplaza,

“Our problem is that even with the echo canceller activated the last word pronounced by the receiver of the call is echoed”

→ Could you please describe how you activated Echo Cancellation? Did you use AT commands or employ a different method?

Please refer to the command !AVEC command: Enable / disable Echo Cancellation mode for audio profile in the document “RC76xx AT Command Reference” at the following link: https://source.sierrawireless.com/resources/airprime/software/rc76xx-at-command-reference-guide/#sthash.rYIKwJyD.dpbs

Thanks,

5

Hi @jerdung,

We are sending the AVEC command to the modem. Specifically, the commands we are sending are:
AT!AVTXG=5,1400
AT!AVEC=5,1
AT+CLVL=3

Regards,
Gustavo.

6

Hi @gplaza,

  1. Please kindly recheck on the Sierra board to see if the issue is still occurring.
  2. Please provide the complete output log of the AT command:
ATI9
AT!IMPREF?
AT!ENTERCND="A710"
AT!AVCFG?
AT!AVSETPROFILE?
AT!AVEC?5
AT!AVTXG?5
AT!AVRXG?5

Thanks,