EC25-AF USB/UAC 16khz

IoT Modules LTE Standard Module
1

Hello, I am running an EC25-AF on USB/UAC and I cannot change the Sample rate to 16 khz. Only 8khz available.
Sound quality is unacceptable (extremely low volume and robotic inbound or even outbound is forcing 8khz).

Firmware version: EC25AFFAR07A14M4G_01.003.01.003
AT+QPCMV=1,2
AT+QDAI=1,0,0,5,0,1,1,1
AT+QCFG=“ims”,1’

Please let me know what I need to do to get an HD voice quality over VoLTE.

Thanks

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2

Dear @osef ,

Thank You for reaching out with your query.

It appears the issue may be software-related but the firmware you are using is the latest one.

As a start can you try to set this configuration using AT command where you can set the echo,noise suppressor and digital gain to improve the sound quality, AT+QAUDMOD :

image
image537×625 60.9 KB

Please try this command and let us know the outcome.

I have a few add on question from my side:
a) The sound quality is coming from Speaker or headset.
b) Did you have a chance to try on another similar EC25 module.

Thank You and Have a Good Day!

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3

@Alvin295337. Hello,
Thanks, but I want to clarify that this is NOT an echo, noise, or gain issue. AT+QAUDMOD will not solve the problem.

The issue is specifically that the USB Audio Class (UAC) interface is hardcoded to 8kHz sample rate in the firmware. Here is the evidence:

  1. AT+QDAI? returns: 1,0,0,5,0,1,1,1 = Confirming the PCM interface is configured for 16kHz

  2. When using AT+QPCMV=1,2 (UAC mode), the USB audio device exposes only 8kHz to the host OS.

  3. Confirmed in your documentation (?) “EC2x&EG9x Voice Over USB and UAC Application Note” explicitly states that PCM data over USB is fixed at 8kHz sampling rate, 16-bit linear, little-endian.

My questions are:

  1. Is there a firmware update or AT command that can change the USB UAC output to 16kHz when an AMR-WB call is active?
  2. If not, which Quectel module supports wideband audio (16kHz) over the USB/UAC interface on a North America network?
4

Dear @osef ,

Good Day,

  1. Is there a firmware update or AT command that can change the USB UAC output to 16kHz when an AMR-WB call is active?
    Currently your using the latest firmware, i will try to check internally for any update of the next firmware release.

  2. If not, which Quectel module supports wideband audio (16kHz) over the USB/UAC interface on a North America network?
    At the moment there is no module on output of 16kHz mostly fixed at 8kHz.Probaly we can have a patch in new firmware.

One more thig, can i know are you testing using our evb kit? and what is the codec used?:
image

if you use ALC5616 realtech it can work when you set AT+QDAI command.

Thank You and Have a Great day!
Thank You!

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