Use the Raspberry Pi to build an Asterisk service to receive calls

What Will I Learn?

Create a Asterisk server by Raspberry Pi
Config 3G dongle in Asterisk

Requirements

A Raspberry Pi 3B
4G TF card
3G dongle with voice support. There is a list of supported models here.
5V/2A Power
Basic linux knowledge

Difficulty

Intermediate

Tutorial Contents

The Basic Principle Diagram

basic_principle_diagram

Basic configuration

1.Download a image from http://www.raspberry-asterisk.org/downloads/. This image is based on Debian and also has been integrated with asterisk and freepbx. In this tutorial I use the raspbx-03-12-2017.zip. It contains Asterisk 13.18.3 and FreePBX 14.0.1.20.

2.Unzip the image and burn this image into the TF card. You can use Etcher with in 3 steps. First select the image file, and then select the TF card, and last click the Flash button to start burning task.

etcher

3.Put your TF card into your RaspberryPi and power on. Get into the system with the default username and password, root / raspberry.

4.(Optional) Config WiFi in this file /etc/wpa_supplicant/wpa_supplicant.conf,

country=GB
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
network={
    ssid="your_wifi_ssid"
    psk="your_wifi_password"
}

Edit the file and save and reboot.

5.Open your browser and input your RaspberryPi's IP. You'll see the administrator configuration page.

admin_configuration_page

Input your username and password and email to create an admin account.

And then the login page comes up.

login_page

6.Login and set the Language and timezone

language_timezone

Then you'll get in the dashboard page.

dashboard

7.Get in Application => Extensions => Add Extension => Add New PJSIP Extension to add a new Extension.

add_new_extension

User Extension is the username to login when you use the SIP App to connect your server.
Display Name is optional.
Secret is the password to login when you use the SIP App to connect your server.
Link to Default User means whether to create a user to manage your SIP account. I set None for secure.

Click the Submit button to save configuration and then click the Apply Config on the upper right corner to make the configuration take effect.

Add another PJSIP extension for testing.

8.Get in Settings => Asterisk SIP Settings page

change to General SIP Settings tab.
In the External Address, input your server domain or your server public IP.
In Local Networks, input your router subnet IP.
In RTP Port Ranges, input 10000 to 10100.
Click the Submit button.

sip_setting

change to Chan PJSIP Settings tab.
set tcp to yes.
click Submit to save and click Apply Config to enable.

sip_setting

9.Open your router config page and add portmapping. You need add ports 5060 and 10000-10100.

!(portmapping)[]

10.Go to http://www.linphone.org/ to download Linphone into your phone and computer as your SIP clients. You can follow these snapshots to finish configurations.

11.Now you can call 102 on your phone and will receive the call on your computer.

Config 3G Dongle

1.Put your SIM card into your 3G Dongle.

2.Open your SSH terminal and connect to your RaspberryPi to setup the Dongle plugin.

root@raspbx:~# install-dongle

dongle

①Input your phone number.
②Input your email to receive the SMS.
③If you don't want to forward sms, leave empty to disable.

And last you will see

Would you like to install a webpage for sending SMS with
chan_dongle? (http://raspbx/sms/) [y/N] y
Enter password for SMS page: 123456

Input y to setup a web UI to send SMS and set a password.

3.Back to the WebUI and get into Connectivity => Trunks => Add Trunk => Add Custom Trunk page.

custom_trunk

4.Under the General tab input a Trunk Name and put your phone number into the Outbound CallerID field.

custom_trunk_general

5.Change to the custom Settings tab and input dongle/dongle0/$OUTNUM$

custom_trunk

If you plugin more than one 3G Dongle on your RaspberryPi, you need confirm your dongle id first with this command.

root@raspbx:~# asterisk -rx "dongle show devices"
ID           Group State      RSSI Mode Submode Provider Name  Model      Firmware          IMEI             IMSI             Number        
dongle0      0     Free       6    5    4       CHN-CUGSM      E1750      11.126.10.00.00   359767033517971  460090019804894  +8617xxxxxxx44

6.Click Submit.

7.Go to Connectivity => Outbound Routes => Add Outbound Route.

Select the Route Settings tab.
Input a name into the Route Name field.
Select the trunk which you just added in the Trunk Sequence for Matched Routes.

outbound