Building an Independent SMS & Call Gateway: The Complete Raspberry Pi, Gammu, and MySQL Guide

In an era dominated by cloud APIs like Twilio, there is still immense value in owning your communication infrastructure. Whether for building a resilient offline alerting system, creating a private 2FA channel, or simply cutting recurring API costs, sometimes you need direct access to the cellular network.

At Comquest, we believe in engineering robust solutions that don't rely on external dependencies when critical paths are involved. In this comprehensive guide, we will walk through transforming a humble Raspberry Pi into a fully-fledged cellular gateway capable of receiving SMS messages and logging incoming call data directly into a MySQL database, managed via phpMyAdmin.

Step 1 System Preparation and Hardware Recognition

Before installing software, ensure your Pi is updated and that the kernel recognizes your USB modem. Connect your modem (with the SIM inserted) to a USB port on the Pi.

Update your package repositories:

sudo apt update && sudo apt upgrade -y

Verify the modem is detected. Run `lsusb` and look for your device manufacturer (e.g., Huawei, QinHeng, etc.). Then, check the system logs to find the device path assignment.

# List USB devices
lsusb

# Check kernel messages for device attachment
dmesg | grep tty

Step 2 Installing the LAMP Stack (Linux, Apache, MySQL/MariaDB, PHP)

We need a database to store incoming messages and a web interface to view them easily. We will use MariaDB (a robust MySQL fork) and phpMyAdmin.

2.1 Install Apache and PHP dependencies

sudo apt install apache2 php php-mysql libapache2-mod-php -y

2.2 Install and Secure MariaDB

sudo apt install mariadb-server -y

# Once installed, secure the installation.
# Follow the prompts: Set root password, remove anonymous users, disallow root login remotely.
sudo mysql_secure_installation

2.3 Install phpMyAdmin

During installation, select apache2 by pressing SPACE, then Enter. Select "Yes" to configure the database with dbconfig-common and set a strong password for the phpMyAdmin user.

sudo apt install phpmyadmin -y

To ensure Apache can find the phpMyAdmin interface, create a symbolic link and restart Apache:

sudo ln -s /usr/share/phpmyadmin /var/www/html/phpmyadmin
sudo systemctl restart apache2

Verification: You should now be able to access `http://your-pi-ip-address/phpmyadmin` in your browser. Log in as `root` with the password you set during the secure installation step.

Step 3 Installing and Configuring Gammu Core

Gammu is the command-line utility that talks to the cellular modem. We need to install it and verify it can communicate with your specific hardware.

sudo apt install gammu gammu-smsd -y

Now, configure Gammu to identify your modem. Run the configuration utility:

sudo gammu-config

This opens a text-based UI. Set the following based on the device path you found in Step 1:

• Port: The device path (e.g., /dev/ttyUSB0 or /dev/ttyUSB2).
• Connection: For most generic USB dongles, try at115200. For Huawei specific dongles, try huawei.

Save the config and exit.

Testing the Connection

Run the identify command. If successful, it will return the modem's manufacturer, model, and IMEI. If it times out, try a different `/dev/tty` port or connection type in the config.

sudo gammu identify

Step 4 Setting up the Gammu Database

Instead of storing SMS messages in text files, we will configure Gammu's daemon (`gammu-smsd`) to use MySQL. First, we must create a dedicated user and import the required database schema.

4.1 Create User and Database

Log into MySQL as root:

sudo mysql -u root -p

Run the following SQL commands (replace `'your_strong_password'` with a real password):

CREATE DATABASE gammu_db;
CREATE USER 'gammu_user'@'localhost' IDENTIFIED BY 'your_strong_password';
GRANT ALL PRIVILEGES ON gammu_db.* TO 'gammu_user'@'localhost';
FLUSH PRIVILEGES;
EXIT;

4.2 Import the Schema

Gammu provides a pre-built SQL schema. Locate it and import it into your new database:

# Locate the schema file (path may vary slightly by distro version)
ls /usr/share/doc/gammu-smsd/examples/sql/

# Import it (assuming it's named mysql.sql.gz)
zcat /usr/share/doc/gammu-smsd/examples/sql/mysql.sql.gz | mysql -u gammu_user -p gammu_db

Step 5 Configuring and Starting the SMS Daemon

This is the final piece of the puzzle. We configure the `gammu-smsd` service to run in the background, monitor the modem, and write data to MySQL.

Edit the SMSD configuration file:

sudo nano /etc/gammu-smsdrc

Replace the contents with the following configuration. Be sure to update the database password and your device port.

[gammu]
# Use the same port and connection that worked in Step 3
device = /dev/ttyUSB0
connection = at115200

[smsd]
# Tell Gammu to use the SQL backend
service = sql
driver = native_mysql
logfile = /var/log/gammu-smsd.log
# Increase debug level if things aren't working (0-255)
debuglevel = 1

# Database connection details set in Step 4
user = gammu_user
password = your_strong_password
pc = localhost
database = gammu_db
# Automatically check security status of PIN
pin = ''

# Ensure incoming calls are logged
checksecurity = 0
hangupcalls = 1

Start the Service

Enable the service to start on boot and start it immediately:

sudo systemctl enable gammu-smsd
sudo systemctl start gammu-smsd

Check the status to ensure it is running without errors:

sudo systemctl status gammu-smsd
# OR check the live logs
tail -f /var/log/gammu-smsd.log

Verification and Conclusion

Your gateway is now active. To verify functionality, send an SMS message to the SIM card number inserted in your Raspberry Pi.

1. Open phpMyAdmin in your browser (`http://your-pi-ip/phpmyadmin`).
2. Select the gammu_db database on the left sidebar.
3. Click on the inbox table. You should see your message appear shortly after sending.
4. Try calling the number. The Pi will hang up (due to hangupcalls = 1), but data will appear in the calls table.