QNavigator - Voice Call via Voice over USB

Hi Experts,

I’m testing EC25 Voice over USB at EVB-KIT.

I removed the audio codec board for this test.

Common and Special tabs followed the default settings.

When I receive the ‘RING’ signal, I set PCMV=1,0 and accept it as ‘ATA’.

The AudioPath_20200508161319414 folder is created in Qnavigator_V1.6.8
and incoming audio is stored in the ‘AudioOut.WAV’ file.
This file plays well.

But, When I transfer the WAV file, the sound plays on the speakerphone for the first few seconds.
After that, no sound is played.
The WAV format is 8K 16bit Mono PCM.

Audio quality is very low in Voice over USB mode.
How can I listen to clean audio?
Do I need additional settings?

Do I need IO, Fsync, Clock, Format, and Mode settings in Voice over USB mode?
If so, what are the exact settings?

Thank you.

Dear Ihuijae,
Thanks for your inquiry again in Quectel forum about voice over USB function.
If you want to test this function, it is better to connect codec chip set firstly, than email to support@quectel.co, to get the test tool to check it. Thanks!