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The ability to communicate with the people on move has expanded a lot by using Cell phones in the resent world especially for the Business Magnets and Professional job holders who needs to communicate during journey in cars. Initially there were only few distributors and People who really needed Mobile Communications capability installed radio-telephones in their cars. In the radio telephone system, there was one central antenna tower per city, with about 25 channels. So the phone in the car needs a powerful Transmitter-big enough to transmit up to 80km. only 2000 consumers could use them, as there were only a few channels but in the 21st century currently there are around 1400 million subscribers in the world. GSM and CDMA are the most successful cell phone technologies present in world, CDMA handsets are chip based where as GSM handsets uses SIM cards, using the GPRS and EDGE facility GSM is successful to Lure the customers but CDMA is still behind GSM due to its limited obesity and other problems. Now Reliance is launching Removable User Identity Module (RIUM) based CDMA phones. This paper explains the overview of Cell phone.