What Is a GSM Network?

The Global System for Mobile Communications (GSM) network is the standard system used by most mobile phone networks around the world. Whether a system uses a cellular network based around broadcast stations or satellite technology connected to signals from orbit, both types can be part of the GSM network. According to statistics accumulated by an organization known as the GSM Association, roughly 80 percent of all mobile phones around the world are part of this network. Phones on this type of network use a Subscriber Identity Module (SIM) card, while those on the major competing technology, Code Division Multiple Access (CDMA), do not.

Frequencies Used

The GSM network operates on different frequencies depending on the system used, whether 2G or 3G. Each frequency is then subdivided into different channels that allow for short bursts of digital information to be sent via the GSM connection. Networks in North America operate on different frequencies than those in Europe or Asia. Much of this has to do with the sheer volume of mobile phone use in certain parts of the world, and the fact that Canada and the United States had already allocated certain frequencies for other uses.

SIM Cards on GSM

Phones on a GSM network typically use a SIM card, which stores data about the phone and its user, allowing that information to be easily transferred to a different device. Many GSM providers use "SIM locking" to keep a person on a particular network during a contracted period of time. Once a contract is complete, then the card can be used in a new phone or on a different network. The competing technology, CDMA, does not use these cards and requires the data stored on a phone to be transferred over manually or through a connection.