USB modem and voice support

[arisav]

We are using Huawei K3520 USB dongle for phone call in Linux environment. Phone call connection is established with AT commands and voice stream starts to flow from /dev/ttyUSB1.
Problem is that voice stream produces only random noise from speaker although we have tried many different codecs in aplay and Audacity.
Which codecs are commonly used for voice streams in modems and how them are activated with AT commands?

[igorpadykov]

Hi Ari

please check

https://boundarydevices.com/cellular-modems-on-i-mx6-boards/ 

regarding codecs one can look at attached Linux Manual

Chapter 28 Advanced Linux Sound Architecture (ALSA) System

voice through usb modem is described in common resources

Voice call through GSM modem - Stack Overflow 

Best regards
igor
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