GSM modules

GSM stands for Global System for Mobile communication. It was introduced in 1991. Using GSM and other technology, we can make phone calls, send SMS (Short Message Service), and connect to the Internet. About 82.4% of the global mobile communication is represented by GSM. In this section of the chapter, we will learn how to choose a perfect GSM module for our Arduino, connect it to the Arduino, make a call using the GSM module, and send SMS. So, let's get started.

Types of GSM module

There are three types of GSM (not GSM modules), each with a different frequency. They are GSM, EGSM, and DCS. We will stick to GSM in this section. For Arduino we will use a GSM shield. There are a number of GSM shields in the market. Look at the following images:

This shield can be used with almost any Arduino:

This shield can be used with any Arduino board:

This board requires an Arduino Uno and 5V external power:

This board requires an Arduino Mega and 5V external power.

Before buying any GSM...