A European standard for digital cellular telephones that has now been widely adopted throughout the world. Under the ETSI standard, GSM telephones contain a SIM smart card that identifies the individual subscriber. GSM 1800 (also DCS 1800 or PCN) network working at1800 MHz. Used notably in Europe, Asia-Pacific and Australia. GSM 1900 (PCS 1900) network working a frequency of 1900 MHz. Used notably in the US and Canada. GSM 900 (also GSM) Used in over 100 countries, particularly in Europe and Asia Pacific. See ETSI , ITU.
