<P> GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second - generation digital cellular networks used by mobile devices such as mobile phones, first deployed in Finland in December 1991 . As of 2014, it has become the global standard for mobile communications--with over 90% market share, operating in over 219 countries and territories . </P> <P> 2G networks developed as a replacement for first generation (1G) analog cellular networks, and the GSM standard originally described as a digital, circuit - switched network optimized for full duplex voice telephony . This expanded over time to include data communications, first by circuit - switched transport, then by packet data transport via GPRS (General Packet Radio Services) and EDGE (Enhanced Data rates for GSM Evolution, or EGPRS). </P>

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