Mobile phone - Wikipedia

 

1er telephone mobile wikipedia

Mobile telephony is the provision of telephone services to phones which may move around freely rather than stay fixed in one location. Telephony is supposed to specifically point to a voice-only service or connection, though sometimes the line may blur. Mobile phones connect to a terrestrial cellular network of base stations (), whereas satellite phones connect to orbiting satellites. L'usage du téléphone mobile s'est progressivement démocratisé, notamment vers la fin des années France Télécom commercialise en le Bi-Bop, premier téléphone portable en France destiné à un public en mobilité urbaine. Le taux de pénétration du mobile dans le monde à cette époque est de 0,6 abonnements pour Le téléphone portable, également appelé téléphone mobile ou téléphone cellulaire, a révolutionné notre vie quotidienne en nous permettant de communiquer sans fil, partout où il y a un réseau de téléphonie mobile. Nous vous proposons de découvrir l’histoire et les évolutions de cette invention qui repose sur la transmission par ondes électromagnétiques., par Audrey4/5(31).


Mobile telephony - Wikipedia


Mobile telephony is the provision of telephone services to phones which may 1er telephone mobile wikipedia around freely rather than stay fixed in one location. Telephony is supposed to specifically point to a voice-only service or connection, though sometimes the line may blur.

Mobile phones connect to a terrestrial cellular network of base stations cell siteswhereas satellite phones connect to orbiting satellites. Both networks are interconnected to the public switched telephone network PSTN to allow any phone in the world to be dialed. In there were estimated to be five billion mobile cellular subscriptions in the world. Public mobile phone systems were first introduced in the years after the Second World War and made use of technology developed before and during the conflict.

Although an uprated manual service 'System 3' was 1er telephone mobile wikipedia to cover most of the UK, automation did not arrive until with 'System 4'. In Bell Labs was the first to propose a cellular radio telephone network. The 1er telephone mobile wikipedia innovation was the development of a network of small overlapping cell sites supported by a call switching infrastructure that tracks users as they move through a network and passes their calls from one site to another without dropping the connection.

In the MTA system was launched in Sweden. The early efforts to develop mobile telephony faced two significant challenges: allowing a great number of callers to use the comparatively few available frequencies simultaneously and allowing users to seamlessly move from one area to another without having their calls dropped.

Both problems were solved by Bell Labs employee Amos Joel who, in applied for a patent for a mobile communications system. As a consequence, Bell Labs concluded that the invention was "of little or no consequence," leading it not to attempt to commercialize the invention, 1er telephone mobile wikipedia.

Bell Labs went on to install the first trial cellular network in Chicago in The first commercial system opened in Chicago in October The advent of cellular technology encouraged European countries to co-operate in the development of a pan-European cellular technology to rival those of the US and Japan.

The GSM standard eventually spread outside Europe and is now the most widely used cellular technology in the world and the de facto standard, 1er telephone mobile wikipedia.

The industry association, the GSMA, now represents countries and nearly mobile network operators. The first mobile phone to enable internet connectivity and wireless email, the Nokia Communicatorwas released increating a 1er telephone mobile wikipedia category of multi-use devices called smartphones.

By over million people around the world accessed the internet or equivalent mobile internet services such as WAP and i-Mode at least occasionally using a mobile phone rather than a personal computer. Mobile phones receive and send radio signals with any number of cell site base stations fitted with microwave antennas. These sites are usually mounted on a tower, 1er telephone mobile wikipedia, pole or building, 1er telephone mobile wikipedia, located throughout populated areas, then connected to a cabled communication network and switching system.

In areas of low coveragea cellular repeater may be used, which uses a long distance high-gain dish antenna or yagi antenna to communicate with a cell tower far outside of normal range, and a repeater to rebroadcast on a small short-range local antenna that allows any cellphone within a few meters to function properly. When the mobile phone or data device is turned on, it registers with the mobile telephone exchangeor switch, with its unique identifiers, and can then be alerted by the mobile switch when there is an incoming telephone call, 1er telephone mobile wikipedia.

The handset constantly listens for the strongest signal being received from the surrounding base stations, and is able to switch seamlessly between sites. As the user moves around the network, the " handoffs " are performed to allow the device to switch sites without interrupting the call. Cell sites have relatively low-power often only one or two watts radio transmitters which broadcast their presence and relay communications between the mobile handsets and the switch.

The switch in turn connects the call to another subscriber of the same wireless service provider or to the public telephone network1er telephone mobile wikipedia, which includes the networks of other wireless carriers. Many of these sites are camouflaged to blend with existing environments, particularly in scenic areas.

The dialogue between the handset and the cell site is a stream of digital data that includes digitised audio except for the first generation analog networks. The technology that achieves this depends on the system which the mobile phone operator has adopted. The technologies are grouped by generation. The nature of cellular technology renders many phones vulnerable to 'cloning': anytime a cell phone moves out of coverage for example, in a road tunnelwhen the signal is re-established, the phone sends out a 're-connect' signal to the nearest cell-tower, identifying itself and signalling that it 1er telephone mobile wikipedia again ready to transmit.

With the proper equipment, it's possible to intercept the re-connect signal and encode the data it contains into a 'blank' phone—in all respects, the 'blank' is then an exact duplicate of the real phone and any calls made on the 'clone' will be charged to the original account. This problem was widespread with the first generation analogue technology, however the modern digital standards such as GSM greatly improve security and make cloning hard to achieve.

Modern handheld cellphones which must have the transmission antenna held inches from the user's skull are limited to a maximum transmission power of 0.

An increasing number of countries, particularly in Europe, now have more mobile phones 1er telephone mobile wikipedia people. According to the figures from Eurostat, the European Union's in-house statistical office, Luxembourg had the highest mobile phone penetration rate at mobile subscriptions per people, closely followed by Lithuania and Italy.

In some developing countries with little "landline" telephone infrastructuremobile phone use has quadrupled in the last decade. Many remote regions in the third world went from having no telecommunications infrastructure to having satellite based communications systems. At present, Africa has the largest growth rate of cellular subscribers in the world, [22] its markets expanding nearly twice as fast as Asian markets.

On a numerical basis, India is the largest growth market, adding about 6 million mobile phones every month. Since the world is operating quickly to 3G and 4G networks, mobile traffic through video is heading high. This is the result of people shifting to smartphones. Law enforcement have used mobile phone evidence in a number of different ways.

Evidence about the physical location of an individual at a given time can be obtained by triangulating the individual's cellphone between several cellphone towers, 1er telephone mobile wikipedia. This triangulation technique can be used to show that an individual's cellphone was at a certain location at a certain time. The concerns over terrorism and terrorist use of technology prompted an inquiry by the British House of Commons Home Affairs Select Committee into the use of evidence from mobile phone devices, prompting leading mobile telephone forensic specialists to identify forensic techniques available in this area.

In the UK in it was claimed that recordings of mobile phone conversations made on the day of the Omagh bombing were crucial to the police investigation, 1er telephone mobile wikipedia. In particular, calls made on two mobile phones which were tracked from south of the Irish border to Omagh and back on the day of the bombing, were considered of vital importance. Further example of criminal investigations using mobile phones is the initial location and ultimate identification of the terrorists of the Madrid train bombings.

In the attacks, mobile phones had been used to detonate the bombs. However, one of the bombs failed to detonate, and the SIM card in the corresponding mobile phone gave the first serious lead about the terrorists to investigators, 1er telephone mobile wikipedia.

By tracking the whereabouts of the SIM card and correlating other mobile phones that had been registered in those areas, police were able to locate the terrorists.

The Finnish government decided in that the fastest way to warn citizens of disasters was the mobile phone network. In Japan, mobile phone companies provide immediate notification of earthquakes and other natural disasters to their customers free of charge.

An interactive menu accessible through the phone's Internet browser notifies the company if the user is safe or in distress. Also, users in the United States can sign up through their provider for free text messages when an AMBER Alert goes out for a missing person in their area.

However, most mobile phone networks operate close to capacity during normal times, 1er telephone mobile wikipedia, and spikes in call volumes caused by widespread emergencies often overload the system just when it is needed the most.

Examples reported in the media where this has occurred include the September 11, attacksthe Northeast blackouts1er telephone mobile wikipedia, the London Tube bombingsHurricane Katrinathe Kiholo Bay earthquakeand the Minnesota bridge collapse. Under FCC regulations, all mobile telephones must be capable of dialing emergency telephone numbersregardless of the presence of a SIM card or the payment status of the account.

Since the introduction of mobile phones, concerns both scientific and public have been raised about the potential health impacts from regular use. For example, at the request of some of their customers, Verizon created usage controls that meter service and can switch phones off, so that children could get some sleep, 1er telephone mobile wikipedia.

In July1er telephone mobile wikipedia, Dr. Ronald Herbermandirector of the University of Pittsburgh Cancer Institutewarned about the radiation from mobile phones. He stated that there was no definitive proof of the link between mobile phones and brain tumors but there was enough studies that 1er telephone mobile wikipedia phone usage should be reduced as a precaution.

Calls could also be shortened or limit mobile phone usage in rural areas. Radiation is found to be higher in areas that are located away from mobile phone towers. There is also a theory it could even occur on the fingers if someone spends a lot of time text messaging on metal menu buttons. InLionel Bercovitch of Brown University in ProvidenceRhode Island, and his colleagues tested 22 popular handsets from eight different manufacturers and found nickel on 10 of the devices.

Between the s and the s, the mobile phone has gone from being an expensive item used by the business elite to a pervasive, 1er telephone mobile wikipedia, personal communications tool for the general population, 1er telephone mobile wikipedia.

In most countries, mobile phones outnumber land-line phones, with fixed landlines numbering 1. In many markets from Japan and South Korea, to Europe, to Malaysia, Singapore, Taiwan and Hong Kong, most children age have mobile phones and the new accounts are now opened for customers aged 6 and 7. Where mostly parents tend to give hand-me-down used phones to their youngest children, in Japan already new cameraphones are on the market whose target age group is under 10 years of age, 1er telephone mobile wikipedia, introduced by KDDI in February The USA also lags on this measure, as in the 1er telephone mobile wikipedia so far, about half of all children have mobile phones.

Mobile phone usage is banned in some countries, such as North Korea and restricted in some other countries such as Burma. Given the high levels of societal mobile phone service penetration, 1er telephone mobile wikipedia, it is a key means for people to communicate with each other. The SMS feature spawned the " texting " sub-culture amongst younger users. Currently, 1er telephone mobile wikipedia, texting is the most widely used data service; 1.

Many phones offer Instant Messenger services for simple, easy texting. Mobile phones have Internet service e. Most mobile internet access is much different from computer access, featuring alerts, weather data, e-mail, search engines, instant messages, and game and music downloading; most mobile internet access is hurried and short.

Because mobile phones are often used publicly, social norms have been shown to play a major role in the usage of mobile phones. Mobile phone use during flights used to be prohibited and many airlines still claim in their in-plane announcements that this prohibition is due to possible interference with aircraft radio communications.

Shut-off mobile phones do not interfere with aircraft avionics. The recommendation why phones should not be used during take-off and landing, even on planes that allow calls or messaging, is so that passengers pay attention to the crew for any possible accident situations, as most aircraft accidents happen on take-off and landing.

Mobile phone use can be an important matter of social discourtesy: phones ringing during funerals or weddings; in toilets, cinemas and theatres. Some book shopslibraries, bathrooms, cinemas, doctors' offices and places of worship prohibit their use, so that other patrons will not be disturbed by conversations.

Some facilities install signal-jamming equipment to prevent their use, although in many countries, including the US, such equipment is illegal.

Many US cities with subway transit systems underground are studying or have implemented mobile phone reception in their 1er telephone mobile wikipedia tunnels for their riders, 1er telephone mobile wikipedia trains, particularly those involving long-distance services, often offer a "quiet carriage" where phone use is prohibited, much like the designated non-smoking carriage of the past.

Most schools in the United States and Europe and Canada have prohibited mobile phones in the classroom, or in school in an effort to limit 1er telephone mobile wikipedia disruptions.

A working group made up of Finnish telephone companies, public transport operators and communications authorities has launched a campaign to remind mobile phone users of courtesy, especially when using mass 1er telephone mobile wikipedia to talk about on the 1er telephone mobile wikipedia, and how to. In particular, the campaign wants to impact loud mobile phone usage as well as calls regarding sensitive matters.

The use of mobile phones by people who are driving has become increasingly common, for example as part of their job, as in the case of delivery drivers who are calling a client, or socially as for commuters who are chatting with a friend, 1er telephone mobile wikipedia. While many drivers have embraced the convenience of using their cellphone while driving, some jurisdictions have made the practice against the law, such as Australia, the Canadian provinces of British ColumbiaQuebecOntario, Nova Scotiaand Newfoundland and Labrador as well as the United Kingdom, consisting of a zero-tolerance system operated in Scotland and a warning system operated in England, Walesand Northern Ireland.

Officials from these jurisdictions argue that using a mobile phone while driving is an impediment to vehicle operation that can increase 1er telephone mobile wikipedia risk of road traffic accidents. Studies have found vastly different relative risks RR. Two separate studies using case-crossover analysis each calculated RR at 4, [44] [45] while an epidemiological cohort study found RR, when adjusted for crash-risk exposure, of 1, 1er telephone mobile wikipedia.

A simulation study from the University of Utah Professor David Strayer compared drivers with a blood alcohol content of 0.

 

Le téléphone portable : histoire et évolutions

 

1er telephone mobile wikipedia

 

A mobile phone, cell phone, cellphone, or hand phone, sometimes shortened to simply mobile, cell or just phone, is a portable telephone that can make and receive calls over a radio frequency link while the user is moving within a telephone service area. The radio frequency link establishes a connection to the switching systems of a mobile phone operator, which provides access to the public. Mobile telephony is the provision of telephone services to phones which may move around freely rather than stay fixed in one location. Telephony is supposed to specifically point to a voice-only service or connection, though sometimes the line may blur. Mobile phones connect to a terrestrial cellular network of base stations (), whereas satellite phones connect to orbiting satellites. L'usage du téléphone mobile s'est progressivement démocratisé, notamment vers la fin des années France Télécom commercialise en le Bi-Bop, premier téléphone portable en France destiné à un public en mobilité urbaine. Le taux de pénétration du mobile dans le monde à cette époque est de 0,6 abonnements pour