GSM

digital cellular communication system used in many countries (based on a variation of TDMA technology)

For other uses, see GSM (disambiguation). Global System for Mobile communications (GSM: originally from Groupe Spécial Mobile) is the most popular standard for mobile phones in the world. Its promoter, the GSM Association, estimates that 82% of the global mobile market uses the standard . GSM is used by over 2 billion people across more than 212 countries and territories. Its ubiquity makes international roaming very common between mobile phone operators, enabling subscribers to use their phones in many parts of the world. GSM differs from its predecessors in that both signaling and speech channels are digital call quality, and so is considered a second generation (2G) mobile phone system. This has also meant that data communication were built into the system using the 3rd Generation Partnership Project (3GPP).
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GSM, Global System for Mobile Communications (digital cellular communication)

Global System for Mobile Communications

Global System for Mobile Communications