Introduction

This blog post describes how to set up a standalone GSM gateway that:

  1. Can receive and make calls in a remote location, operating in standalone mode.
  2. Is easy to set up and maintain.
  3. Is budget-friendly, with minimal expenses beyond hardware.

Hardware

  • SD Card
  • Raspberry Pi 4B
  • LTE Hat (Waveshare SIM7600E-H)

Software

  • Debian-based OS for Raspberry Pi
  • Asterisk as the VoIP Server
  • Other essential Linux utilities

Installing the OS on Raspberry Pi

32-bit OS

Use the official RASPIOS Lite image: Download RASPIOS Lite 32-bit

To ensure 32-bit mode:

vim /boot/config.txt
# or
nano /boot/config.txt

Add:

arm_64bit=0

64-bit OS

⚠️ Asterisk is not available in the 64-bit repository by default.

Alternative approach:

  • Install a 64-bit base system
  • Add source repositories
  • Build Asterisk from source

Installing Asterisk and Required Modules

Set Up the Basic System

sudo apt update && sudo apt upgrade -y
sudo apt install -y build-essential libasound2-dev libsqlite3-dev autoconf automake git zsh screen vim asterisk asterisk-dev mosh libtool pkg-config

Optional (but essential): Oh My Zsh

sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"

Compiling G.729 Codecs for ARM with BCG729

Based on “Compiling g729 codecs for ARM on Raspberry Pi B+ with bcg729”

Compiling the BCG729 Library

mkdir -p $HOME/src
cd $HOME/src
wget http://download-mirror.savannah.gnu.org/releases/linphone/plugins/sources/bcg729-1.0.2.tar.gz
tar xzf bcg729-1.0.2.tar.gz
cd bcg729-1.0.2
./configure --libdir=/lib
make
sudo make install

Compiling G.729 Codecs

cd $HOME/src 
git clone git@github.com:arkadijs/asterisk-g72x.git 
cd asterisk-g72x 
./autogen.sh 
DESTDIR=/usr/lib/asterisk/modules ./configure --with-bcg729 
make 
sudo make install

Test Modules in Asterisk

sudo systemctl restart asterisk
sudo asterisk -rvvv
asterisk*CLI> core show translation recalc 10

Installing Channel Drivers

Quectel & Simcom Modules

cd $HOME/src
# git clone git@github.com:IchthysMaranatha/asterisk-chan-quectel.git
cd asterisk-chan-quectel
autoupdate
./bootstrap
DESTDIR=/usr/lib/asterisk/modules ./configure --with-astversion=16.28.0
make
sudo make install

chan_dongle for USB Modems

cd $HOME/src
git clone git@github.com:wdoekes/asterisk-chan-dongle.git
cd asterisk-chan-dongle
autoupdate
./bootstrap 
DESTDIR=/usr/lib/asterisk/modules ./configure --with-astversion=16.28.0
make 
sudo make install

Happy hacking! 🚀