GSM Modem – Working & Its Applications

In 1970 this idea was developed at bell laboratories which are used for a mobile communication system to transmit mobile data as well as voice service.
It is digital cellular technology, its stands for Global system for mobile communication, and this technology is developed by using digital technology.
The market share of digital cellular subscribers around the world is above 70% and GSM technology supports above 1 billion mobile subscribers around the world in the above 210 countries.

Definition of GSM Modem

The GSM technology is transmitting mobile voice and data services from fundamental to complex.
GSM operates at the 850MHz, 900MHz, 1800MHz, and 1900MHz frequency bands.
It was developed as a digital system using the time division multiple access (TDMA) technique for communication purposes.

It reduces the data, then sends it down through a channel with two different streams of client data, each in its particular time slot.
The digital system can carry 64 kbps to 120 Mbps of data rates.
GSM has various cell sizes such as macro, micro, Pico, and umbrella cells. every cell varies as per the implementation domain.
The TDMA is a technique used for assigning different time slots to each user on the same frequency.
It can easily adapt to data transmission and voice communication and can carry 64kbps to 120Mbps of data rate.

GSM modem duly interfaced with MC through the level shifter IC Max232. The SIM card mounted GSM modem upon receiving digit command by SMS from any cell phone sends that data to the MC through serial communication. While the program is executed, the GSM modem receives the command ‘STOP’ to develop an output at the MC, the contact point of which is used to disable the ignition switch.
The command so sent by the user is based on a notification received by him through the GSM modem ‘ALERT’ a programmed message only if the input is driven low. The complete operation is displayed over a 16×2 LCD.