Cellular telephone

With third generation (3G) networks which are also known as IMT-2000 networks, about three out of four networks are on WCDMA (also known as UMTS) standard, usually seen as the natural evolution path for GSM and TDMA networks. One in four 3G networks is on the CDMA2000 1x EV-DO technology, fly sl400m. Some analysts count a previous stage in CDMA evolution, CDMA2000 1x RTT, as a 3G technology whereas most standardization experts count only CDMA2000 1x EV-DO as a true 3G technology. Because of this difference in interpreting what is 3G, there is a wide variety in subscriber counts. As of June 2007, on the narrow definition there are 200 million subscribers on 3G networks. By using the more broad definition, the total subscriber count of 3G phone users is 475 million, fly v09. While some systems of payment are 'pay as you go' where conversation time is purchased and added to a phone unit via an Internet account or in shops or ATMs, other systems are more traditional ones where bills are paid by regular intervals. Pay as you go (also known as "pre-pay") accounts were invented simultaneously in Portugal and Italy and today form more than half of all mobile phone subscriptions. USA, Canada, Japan and Finland are among the rare countries left where most phones are still contract-based, fly v40. In less than twenty years, mobile phones have gone from being rare and expensive pieces of equipment used primarily by the business elite to a pervasive low-cost personal item. In many countries, mobile phones now outnumber land-line telephones, with most adults and many children using mobile phones. In the United States, 50% of children are using mobile phones. In many young adults' households the mobile phone has supplanted land-line telephones, fly x10. In some areas in developing countries with scarce fixed-line infrastructure, the mobile phone has introduced telephony as such. It has given poor people in isolated communities access to services such as medical and legal advice. However, the mobile phone is also banned in some countries like North Korea. With high levels of mobile telephone penetration, mobile culture has evolved where the phone is a key social tool with people relying on their mobile phone address book to keep in touch with friends, not least by SMS, and a whole culture of "texting" has developed from this, fly x3. Since the first person-to-person SMS text message was sent in Finland in December 1993, today "texting" has become the most widely used data service on the planet, with 1.8 billion people as active users of SMS texting and the service generated 80 billion dollars of service revenues in 2006 (source ITU). Many phones offer Instant Messenger services to increase the simplicity and ease of texting on phones, fly x7. Mobile phones in Japan, offering Internet capabilities such as NTT DoCoMo's i-mode, offer text messaging via standard e-mail. In several countries internet access from mobile phones has become used by more internet users than access from PCs. Japan was first, followed by South Korea, China and India. In Europe several countries have proportions of 30% - 40% of all internet users now accessing via mobile phones. Most mobile internet access is significantly different from PC based internet access, with services such as alerts, weather information, e-mail, search, IM and downloads of games and music favored over classic "web browsing", fly x7a. Most mobile internet use is of short duration and in a hurry. The mobile phone itself has also become a fashion object of totemic value, 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 5 billion in 2006 according to Informa. Mobile phone etiquette has become an important issue with phones ringing at funerals, weddings,toilets,cinemas, and plays. Users often speak at increased volume which has led to places like book shops, libraries, bathrooms, movie theaters, doctors' offices, and houses of worship posting signs prohibiting the use of mobile phones, and in some places installing signal-jamming equipment to prevent usage (although in many countries including the United States, such equipment is currently illegal), fly z007. Some new buildings such as auditoriums have installed wire mesh in the walls (turning the building into a Faraday cage) which prevents any signal getting through, but does not contravene the jamming laws. Trains, particularly those involving long-distance services, often offer a "quiet car" where phone use is prohibited, much like the designated non-smoking car in the past. However many users tend to ignore this as it is rarely enforced, especially if the other cars are crowded and they have no choice but to go in the "quiet car", fly z200. Mobile phone use on aircraft is also prohibited and many airlines claim in their in-plane announcements that this prohibition is due to possible interference with aircraft radio communications even though this has been proven to be completely untrue. There is no interference from mobile phones that remain turned to aircraft avionics, as the airline safety staff well know as a typical airliner has dozens of phones that were forgotten to be turned off, on every flight, mobiado professional. The real nuisance of phones that are on while planes take off and land, is that they disrupt the mobile phone networks on the ground. With busy airports landing jumbo jets every few minutes, the ground based mobile phone networks would experience continuous peaks in brief traffic overloads as hundreds of passenger phones would attempt to connect to the ground base stations, haier v280. As customers want to be connected on planes, now several airlines are experimenting with tiny base stations and antenna systems installed into the cabin of the airplane, allowing low power short range connection of any phones onboard to maintain a connection to the base station in the plane. In this way they would not attempt to find connection to the ground base stations as the planes take off and land, mobiado professional executive model. At the same time the airlines could offer phone services to their travelling passengers either as full voice and data servies, or initially only as SMS text messaging and similar services. Qantas the Australian airline is the first airline to run a test airplane in this configuration in the Autumn of 2007. Emirates have announced plans to allow limited mobile phone usage on some flights, haier m1000. In any case, there are inconsistencies between practices allowed by different airlines and even on the same airline in different countries. For example, Northwest Airlines may allow the use of mobile phones immediately after landing on a domestic flight within the US, whereas they may state "not until the doors are open" on an international flight arriving in the Netherlands. In April 2007 the US Federal Communications Commission officially grounded the idea of allowing passengers to use phones during a flight, haier p7. In a similar vein signs are put up in UK petrol stations prohibiting the use of mobile phones due to possible safety issues. Most schools in the United States have prohibited mobile phones in the classroom due to the large number of class disruptions that result from their use, the potential for cheating via text messaging, and the possibility of photographing someone without consent. In the UK, possession of a mobile phone in an examination can result in immediate disqualification from that subject or from all their subjects, haier v20.