Mobile phones are wireless electronic device used for communication purposes over a network of specialized stations known as cell sites. These sites are microwave antennas fixed in place of populated areas. It is connected to a cabled cellular network relatively low-power radio transmitters which broadcast the presence and relay communications between mobile handsets and the switch. Mobile phones has a transmitter and receiver combined in single housing that transmits voice and data to cell sites, approximately not more than 800 to 1300 meters away.
Several mobile phones may support many functional services like sending SMS (Short Message Service) for text messaging, MMS (Multimedia Messaging Service) for sending and receiving photos and videos, access to internet services such as WAP and i-Mode, emails, downloading videos and games, Bluetooth connectivity, infrared, camera with video recorder, radio connection, music (MP3), other mobile phones offers advance services called the Third generation (3G) or video telephony/calling.
Generally, mobile phones obtain power supply from batteries that can be recharged from portable batteries, USB port, and cigarette lighter socket in a car using an adapter or from solar panel or a dynamo. There are three kinds of most common used mobile phone batteries such as nickel metal-hydride as they are low in weight and size. Lithium-ion as they are lighter and do not have voltage depression and lithium-polymer batteries as they are lower weight and make the battery a shape other than strict rectangular prism.
In addition to the battery, All GSM mobile phones require a small microchip called a SIM card Or Subscriber Identity Module, to function. It is placed underneath the battery of a mobile phone in the rear unit approximately the size of a postage stamp and when properly activated the phone configures the data and information about the mobile phone. Other mobile phones do not use a SIM Card can be activated by using a special digit to access the NAM or Name or programming menu.
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