The mobile phones have built –in GSM module which enables them to
connect with any cellular network around the globe. The GSM stands for Global
System for Mobile communications. In certain applications the microcontroller
based systems has to be connected with the GSM network which will enable a user
to control the system by sending messages or making a call. The systems can
also send messages to the user to alert or inform about the status of the
system running. In all such cases a separate GSM module is used rather than
using the mobile phones.
There are GSM modules available which can do serial communication
with microcontroller based systems. The communication is done by sending or
receiving AT
commands with the GSM module. This
particular project demonstrates how to interface a GSM module and dial
a call using the standard PS2 keyboard with the help of an Arduino board.
The PS2 keyboard can send the equivalent ASCII value of the key
which has been pressed to a host device into which it is connected to. The PS2
Keyboard also uses a simple synchronous serial protocol called PS2 using only
two wires for communication. Due to their simplicity in interfacing the PS2
keyboards and GSM modules are widely used with simple microcontroller based
boards.