The evolution of mobile phones• The analog mobile phone system, 1G, voice-only service. The system is in this era, such as the NMT, AMPS, DataTac started for the first time in 1980.• A digital mobile telephone system, 2G system, which is in this era, such as GSM, PDC, cdmaOne, both voice and data. Circuit switching is a 9.6-14.4 kbps speed.• 2.5 G mobile phone system, a digital packet switching system starts from use. The system is in this era, such as GPRS and 20-40 kbps speed.• 2.75 G systems in this era, such as CDMA2000 1xRTT, EDGE, the speed is less than 10 kbps.• A digital 3G system, a mobile phone that is capable of communicating with all the data, including video and audio. The system is in this era, such as W-CDMA, TD-SCDMA, 1x-EVDO, more than 144 kbps speed CDMA2000.• 3.5 G mobile phone system, a digital with high data transmission speed over HSDPA in 3G, such as W-CDMA.• 4G mobile system the Real-Digital can connect to a ground-3 data CDMA PA-H and connect to the connection and Wi-Max ewifi images and sound is the same information.
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