mobile phones by egfalcon


									Early mobile phones were usually bulky and permanently installed in vehicles, they provided
limited service because only a few frequencies were available for a geographic area. Modern
cellular cell phones or hand phones make use of the cellular network concept, where
frequencies are used repeatedly within a city area, allowing many more users to share access
to the radio bandwidth. A mobile phone allows calls to be placed over a wide geographic area,
generally the user is a subscriber to the phone service and does not own the base station. By
contrast, a cordless telephone is used only within the range of a single, private base station.

A mobile phone can make and receive telephone calls to and from the public telephone
network which includes other mobiles and fixed line phones across the world. It does this by
connecting to a cellular network provided by a mobile network operator. In addition to
telephony, modern mobile phones also support a wide variety of other services such as text
messaging, MMS, email, Internet access, short range wireless communications (infrared,
Bluetooth), business applications, gaming and photography. Mobile phones that offer these
more general computing capabilities are referred to as smartphones.

The first commercially automated cellular network (1G) was launched in Japan by NTT in
1979, initially in the metropolitan area of Tokyo. Within five years, the NTT network had been
expanded to cover the whole population of Japan and became the first nationwide 1G network.
In 1981, this was followed by the simultaneous launch of the Nordic Mobile Telephone (NMT)
system in Denmark, Finland, Norway and Sweden. NMT was the first mobile phone network
featuring international roaming. The first 1G network launched in the USA was Chicago based
Ameritech in 1983 using the Motorola DynaTAC mobile phone. Several countries then followed
in the 1980s including the UK, Mexico and Canada. The first modern network technology on
digital 2G cellular technology was launched by Radiolinja in 1991 in Finland on the GSM
standard, which also marked the introduction of competition in mobile telecoms when
Radiolinja challenged incumbent Telecom Finland who ran a 1G NMT network.

Low end mobile phones are often referred to as feature phones, and offer basic telephony, as
well as functions such as playing music and taking photos, and sometimes simple applications
based on generic managed platforms such as Java ME or BREW. Handsets with more advanced
computing ability through the use of native software applications became known as smart
phones. The first Smartphone was the Nokia 9000 Communicator in 1996 which added PDA
functionality to the basic mobile phone at the time. As miniaturization and increased
processing power of microchips has enabled ever more features to be added to phones, the
concept of the smart phone has evolved, and what was a high end smart phone five years
ago, is a standard phone today.

Other features that may be found on mobile phones include GPS navigation, music (MP3) and
video(MP4) playback, RDS radio receiver, alarms, memo recording, personal digital assistant
functions, ability to watch streaming video, video download, video calling, built in cameras and
camcoder with autofocus and flash, ringtones, games, PTT, memory card reader (SD), USB
(2.0), dual line support, infrared, Bluetooth (2.0) and WiFi connectivity, instant messaging,
Internet email and browsing and serving as a wireless modem. Nokia and the University of
Cambridge demonstrated a bendable cell phone called the Morph. Some phones can make
mobile payments via direct mobile billing schemes or through contact less payments if the
phone and point of sale support Near Field Communication (NFC). Some of the largest mobile
phone manufacturers and network providers along with many retail merchants support, or
plan to support, contact less payments through NFC equipped mobile phones.

GSM mobile phones require a small microchip called a Subscriber Identity Module or SIM Card,
to function. The SIM card is approximately the size of a small postage stamp and is usually
placed underneath the battery in the rear of the unit. The SIM securely stores the service-
subscriber key (IMSI) used to identify a subscriber on mobile telephony devices. The SIM card
allows users to change phones by simply removing the sim card from one mobile phone and
inserting it into another mobile phone or broadband telephony device. A SIM card contains its
unique serial number, internationally unique number of the mobile user (IMSI), security
authentication and ciphering information, temporary information related to the local network ,
a list of the services the user has access to and two passwords.

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