What Is GSM in Cellular Networking?

GSM is short for Global System for Mobile Communications

Global System for Mobile communications is the most popular cell phone standard. According to the GSM Association, which represents the interests of the worldwide mobile communications industry, roughly 80 percent of the world uses GSM technology for wireless calls.

Which Networks Are GSM?

Here's a quick breakdown of just a few mobile carriers and that use GSM:

  • T-Mobile
  • AT&T
  • Indigo Wireless
  • Pine Cellular
  • TerreStar

In the United States, Sprint and Verizon use CDMA instead of GSM.


GSM offers wider international roaming capabilities than other U.S. network technologies and can enable a cell phone to be a “world phone." With GSM, switching SIM cards activates different phones to the same network account. In addition, GSM allows for simultaneous data and voice operation—something CDMA cannot manage.

GSM Logo

GSM carriers offer roaming contracts with other GSM carriers and typically cover rural areas more completely than competing CDMA carriers, and often without roaming charges.

Technical Information About GSM

The origins of GSM start in 1982 when the Groupe Spécial Mobile was created by the European Conference of Postal and Telecommunications Administrations to design a pan-European mobile technology.

GSM didn't begin being used commercially until 1991, where it was built using TDMA technology.

GSM provides standard features like phone call encryption, data networking, caller ID, call forwarding, call waiting, SMS, and conferencing.

This cell phone technology works in the 1900 MHz band in the US and the 900 MHz band in Europe and Asia. Data is compressed and digitized, and then sent through a channel with two other data streams, each using their own slot.

  • What does 'GSM unlocked' mean?

    A phone labeled as a GSM unlocked phone is a device that can work with any compatible mobile service provider. Unlike a locked phone, you don't have to purchase a contract with a specific cellular network for the phone. You can choose to activate the device with any GSM mobile carrier.

  • What does 'GSM carrier' mean?

    A GSM carrier is a mobile network provider that uses the Global System for Mobile communications cellular technology. GSM carriers such as AT&T and T-Mobile provide service to GSM phones while Code Division Multiple Access (CDMA) carriers are only compatible with CDMA phones.

Was this page helpful?