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A mobile phone, also known as a cell phone, smart phone, mobile, or hand phone, is an electronic telecommunications device with the same basic capability as a conventional fixed line telephone, but which is also entirely portable and is not required to be connected with a wire to the telephone network. Most current mobile phones connect instead to the network using a wireless radio wave transmission technology. The mobile phone communicates via a network of base stations which are in turn linked to the conventional telephone network.
In addition to the standard voice function of a telephone, a mobile phone can support many additional services such as SMS for text messaging, packet switching for access to the Internet and MMS for sending and receiving photos and video.
Some of the world's largest mobile phone manufacturers include Alcatel, Audiovox, Fujitsu, Kyocera (formerly the handset division of Qualcomm), LG, Motorola, NEC, Nokia, Panasonic (Matsushita Electric), Philips, Sagem, Samsung, Sanyo, Sharp, Siemens, SK Teletech, Sony Ericsson, and Toshiba.
There are also specialist communication systems related to, but distinct from mobile phones, such as satellite phones and Professional Mobile Radio. Mobile phones are also distinct from cordless telephones, which generally operate only within a limited range of a specific base station.
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Radio phones have a long and varied history that stretches back to the 1950s, with hand-held cellular radio devices being available since 1983. Due to their low establishment costs and rapid deployment, mobile phone networks have since spread rapidly throughout the world, outstripping the growth of fixed telephony.
In most of Europe, wealthier parts of Asia and Latin America, Australia, Canada and the US, mobile phones are now widely used, with the majority of the adult, teenage, and even child population owning one. At present India and China have the largest growth rates of cellular subscribers in the world. The availability of Prepaid or pay as you go services, where the subscriber does not have to commit to a long term contract, has helped fuel this growth.
The mobile phone has become ubiquitous because of the interoperability of mobile phones across different networks and countries. This is due to the equipment manufacturers all working to the same standard, particularly the GSM standard which was designed for Europe-wide interoperability. All European nations and some Asian nations chose it as their sole standard, while in Japan and South Korea another standard, CDMA, was selected.
In less than twenty years, mobile phones have gone from being rare and expensive pieces of equipment used by businesses to a pervasive low-cost personal item. In many countries, mobile phones now outnumber land-line telephones, with most adults and many children now owning mobile phones. It is not uncommon for young adults to simply own a mobile phone instead of a land-line for their residence. In some developing countries, where there is little existing fixed-line infrastructure, the mobile phone has become widespread.
With high levels of mobile telephone penetration, a mobile culture has evolved, where the phone becomes a key social tool, and people rely on their mobile phone addressbook to keep in touch with their friends. Many people keep in touch using SMS, and a whole culture of "texting" has developed from this. The commercial market in SMS's is growing. Many phones even offer Instant Messenger services to increase the simplicity and ease of texting on phones. Cellular phones in Japan, offering internet capabilities such as NTT DoCoMo's i-mode, offer text messaging via standard email.
The mobile phone itself has also become a totemic and fashion object, with users decorating, customizing, and accessorizing their mobile phones to reflect their personality. This has emerged as its own industry. The sale of commercial ringtones exceeded $2.5 billion in 2004 [1].
Mobile phone etiquette has become an important issue with mobiles ringing at funerals, weddings, movies and plays. Users often speak at increased volume, with little regard for other people nearby. It has become common practice for places like bookshops, libraries, movie theatres, and houses of worship to post signs prohibiting the use of mobile phones, sometimes even installing jamming equipment to prevent them. The US intercity passenger system Amtrak offers a "quiet car" where phone use is prohibited, much like the designated non-smoking cars in the past. Mobile phone use on aircraft is also prohibited.
Cameraphones and videophones that can capture video and take photographs are increasingly being used to cover breaking news. Stories like the London Bombings, the Indian Ocean Tsunami and Hurricane Katrina have been reported on by cameraphone users on news sites like NowPublic and photosharing sites like Flickr.
In Japan, cellular phone companies provide immediate notification of earthquakes and other natural disasters to their customers free of charge. In the event of an emergency, disaster response crews can locate trapped or injured people using the signals from their mobile phones; an interactive menu accessible through the phone's internet browser notifies the company if the user is safe or in distress.
See main article: Mobile phone features
Mobile phones are often packed with features that offer users far more than just the capability to send text messages and make voice calls. These may include internet browsing, music (MP3) playback, personal organisers, email, watch/alarm, built-in cameras, ringtones, security measures (e.g. pin codes), SIM blocks, games, radio, Push to talk, infrared and bluetooth connectivity, and call registers.
Mobile phones and the network they operate under vary significantly from provider to provider, and even from nation to nation. However, all of them communicate through electromagnetic radio waves with a base station (which is a special radio mast or tower designed for the purpose). The phones have a low power transceiver that is typically designed to transmit voice and data up to a few kilometers to where the tower is located. The handset constantly listens for the nearest tower with the strongest signal. Once found, the handset informs that tower of its own unique identifier, and alerts the mobile phone network that it is ready and standing-by to receive telephone calls. This cycle is then repeated as the phone roams around the network and new towers appear in the handset's range.
Towers have high power radio transmitters which broadcast their presence, and relay communications to and from the mobile handsets. The tower is connected to the telephone network by a high-capacity link. The base station connects to the operator's backbone network and the wider public telephone network as well as the networks of other mobile phone operators.
The dialogue between the handset and the tower is a stream of digitized audio. The technology that achieves this depends on the system which the mobile phone operator has adopted. Some technologies include AMPS for analogue, and TDMA, CDMA, GSM, GPRS and UMTS for digital communications. Each network operator also has a unique radio frequency chosen from a small number of standard frequencies allocated to each technology.
See main article: Mobile phone radiation and health
As with many new technologies, concerns have arisen about the effects on health from using a mobile telephone. There is a small amount of scientific evidence for an increase in certain types of rare tumors (cancer) in long-time, heavy users. More recently a pan-European study provided significant evidence of genetic damage under certain conditions. Some researchers also report the mobile phone industry has interfered with further research on health risks. So far, however, the World Health Organization Task Force on EMF effects on health has no definitive conclusion on the veracity of these allegations. (see also Electromagnetic radiation hazard). It is generally thought, however, that RF is incapable of producing any more than heating effects, as it is considered non-ionizing radiation; in other words, it lacks the energy to disrupt molecular bonds such as occurs in genetic mutations.
See main article: Mobile phones and driving safety
Another controversial but perhaps more lethal health concern is the correlation with road traffic accidents. Several studies have shown that motorists have a much higher risk of collisions and losing control of the vehicle while talking on the mobile telephone simultaneously with driving, even when using "hands-free" systems. One such study conducted by the American television show Mythbusters concluded that use of mobile phones while driving poses the same risk as someone operating a vehicle while under the influence of alcohol.
Accidents involving a driver being distracted by talking on a mobile phone have begun to be prosecuted as negligence similar to driving while intoxicated. In some jurisdictions, such as Ireland, Japan, Singapore, Brazil, Australia, Austria, the United Kingdom and France, as well as several states in the United States driving while using a mobile phone is illegal, though an exception is often made if the phone is equipped with a handsfree system. In Canada it is banned in Newfoundland (Dec 2002) with fines up to US$180.
Early mobile phones did not have much security designed in. Some problems with these models were "cloning", a variant of identity theft, and "scanning" whereby third parties in the local area could intercept and eaves drop in on calls. Analogue phones could also be listened to on some radio scanners.
Although more recent digital systems (such as GSM) have attempted to address these fundamental issues, security problems continue to persist. Vulnerabilities (such as SMS spoofing) have been found in many current protocols that continue to allow the possibility of eavesdropping or cloning.
There is a great deal of active research and development into mobile phone technology that is currently underway. Some of the improvements that are being worked on are:
For a list of what mobile phones are called in other countries around the world, see the following article: Mobile phone terms across the world