Category: VOIP

I have been trying to make a VOIP calling device with a raspberry pi3 and MIC+ using PJSUA. There seems to be a bug when attempting to make/receive a call.

pjsua-armv7l-unknown-linux-gnueabihf: ../src/pjmedia/conference.c:1895: get_frame: Assertion `frame->size == conf->samples_per_frame * conf->bits_per_sample / 8' failed.

To fix this: change /root/.asoundrc

options snd_rpi_googlevoicehat_soundcard index=0

pcm.softvol {
type softvol
slave.pcm dmix
period_size 320
buffer_size 10240
control{
name Master
card 0
}
}

pcm.micboost{
type softvol
slave.pcm dsnoop
period_size 320
buffer_size 10240
control {
name Micro
card 0
}
min_dB -10.0
max_dB 50.0
resolution 256}

pcm.!default {
type asym
playback.pcm "plug:softvol"
capture.pcm "plug:micboost"
}

ctl.!default {
type hw
card 0
}

If it still does not work then refer to this:
https://community.volumio.org/t/change-the-default-alsa-sample-rate-to-44100/116
http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/2010-April/010721.html

Download and extract

apt-get install build-essential automake autoconf libasound2-dev
wget https://github.com/pjsip/pjproject/archive/2.10.tar.gz
tar -xvf 2.10.tar.gz
cd pjproject-2.10

Modify pjlib/include/pj/config_site.h

#define PJMEDIA_AUDIO_DEV_HAS_ALSA 1

Compile

./configure && make dep && make
/root/pjproject-2.10/pjsip-apps/bin/pjsua-armv7l-unknown-linux-gnueabihf  --config /root/pjproject-2.10/pjsip-apps/bin/pjsip.conf

Huawei E1750 3G Modem has the ability to call, but the feature is disabled by default.

Most online solutions on enabling the voice feature do not work, including manual AT commands, the cracked version of dc unlocker or huawei unlocker.
I am not sure what the actual dc unlocker voice activation (4 credits) does, but it successfully activated the voice feature.

This video is just me trying out the dc unlocker voice activation (with credits T_T) in a virtual machine.

After this, the raspbx chan_dongle works 😀

Damage: 4 credits

Video Tutorial and Walkthrough