GSM Explained

How Cell Phone Networks Work

GSM brings voice waves to your phone
GSM brings voice waves to your phone. Innocent/Cultura/GettyImages

What is GSM?

GSM technology is the technology that you (most probably) and 80% of mobile users use for making calls on their mobile phones. In a way, it is the standard and default wireless protocol used for mobile communication.

GSM started back in 1982 and was then named after the group that devised it, Groupe Spécial Mobile, whence the GSM acronym. The official protocol was launched itself in Finland in 1991. It is now called Global Systems for Mobile communications.

GSM is considered a 2G (second generation) protocol. It works with cells, which is why a GSM network is also called a cellular network, and phones working on GSM are called cell phones. Now what is a cell? A GSM network is split into cells, each one of which covers a small area. Devices (phones) are then located and communicated with through these cells.

A GSM network consists mainly of connection devices (gateways etc.), repeaters or relays, which people commonly call antennas – these massive metal structures that stand as high towers -, and the mobile phones of users.

The GSM or cellular network is also a platform for 3G communication, which carries data over the existing network for Internet connectivity. 

The SIM Card

Each mobile phone is connected to a GSM network and identified in it through a SIM (Subscriber Identity Module) card, which is a small card that is inserted inside the mobile phone. Each SIM card is assigned a phone number, hard-coded into it, that is used as unique identification element for the device on the network. This is how your phone rings (and not anyone else’s) when someone dials your mobile phone number.


GSM people have developed a communication system that is a cheap alternative to the somewhat expensive voice communication; it is the Short Messaging System (SMS). This consists of transmitting short text messages between mobile phones using phone numbers for addressing.

Pronunciation: gee-ess-emm

Also Known As: cellular network, cell network

GSM and Voice over IP

GSM or cellular calls add a lot of weight in the monthly budget of many people. Thanks to Voice over IP (VoIP), which bypasses the cellular network and channels the voice as data over the Internet, things have changed considerably. Since VoIP uses the Internet which is already free, VoIP calls are mostly free or very cheap compared to GSM calls, especially for international calls. 

Now, apps like Skype, WhatsApp, Viber, LINE, BB Messenger, WeChat and dozens of others offer free calls worldwide among their users. Some of them offer calls to other destinations much cheaper than GSM calls. This is causing a decline in the number of GSM calls being placed, and SMS is facing extinction with free instant messaging. 

However, VoIP has not been able to beat GSM and traditional telephony on voice quality. GSM voice quality still remains much better than Internet-based calls as the latter does not ensure reliability and the line is not dedicated as with GSM.