GSM, also known as Global System for Mobile Communication, is defined as the cell phone technology that is popular in many parts of the world.
GSM technology was first launched in Finland in 1991. GSM technology usually operates at frequency band of either 900 MHz or 1800 MHz. The various features of the GSM include the use of encryption to make calls, data networking, group III facsimile services, SMS (Short Messaging Service), call forwarding, caller ID, call waiting, and multi-party conferencing.
GSM is one of the most widely used digital wireless technologies and is a second-generation (2G) mobile phone system. GSM technology has the advantage of providing users with the facility of international roaming capabilities. Another advantage of GSM technology is the use of SIM (Subscriber Identity Module) cards that act as digital identity of the mobile user. This allows an easy exchange of from one mobile to another without any cell phone service activation.