View source for Mobile phone features

[[File:Phone hardware.png|thumb|Hardware-side view of a typical smartphone]]
The '''features of mobile phones''' are the set of capabilities, services and applications that they offer to their users. Mobile phones are often referred to as [[Engineering:Feature phone|feature phone]]s, and offer basic telephony.{{clarify|see talk page|date=December 2011}} Handsets with more advanced computing ability through the use of native code try to differentiate their own products by implementing additional functions to make them more attractive to consumers. This has led to great innovation in mobile phone development over the past 20 years.

The common components found on all phones are:

* A number of metal–oxide–semiconductor (MOS) [[Engineering:Integrated circuit|integrated circuit]] (IC) chips.
* A battery (typically a [[Engineering:Lithium-ion battery|lithium-ion battery]]), providing the power source for the phone functions.
* An input mechanism to allow the user to interact with the phone. The most common input mechanism is a keypad, but touch screens are also found in smartphones.
* Basic mobile phone services to allow users to make calls and send text messages.
* All GSM phones use a [[SIM card]] to allow an account to be swapped among devices. Some CDMA devices also have a similar card called a [[Engineering:Removable User Identity Module|R-UIM]].
* Individual GSM, WCDMA, IDEN and some satellite phone devices are uniquely identified by an [[International Mobile Equipment Identity]] (IMEI) number.

All mobile phones are designed to work on [[Engineering:Cellular network|cellular network]]s and contain a standard set of services that allow phones of different types and in different countries to communicate with each other.  However, they can also support other features added by various manufacturers over the years:

* [[Engineering:Roaming|roaming]] which permits the same phone to be used in multiple countries, providing that the [[Engineering:Mobile phone operator|operators]] of both countries have a [[Engineering:Roaming|roaming agreement]].
* send and receive data and [[Engineering:Fax|fax]]es (if a computer is attached), access [[Wireless Application Protocol|WAP]] services, and provide full [[Internet]] access using technologies such as GPRS.
* applications like a  [[Physics:Clock|clock]], [[Biology:Alarm clock|alarm]], [[Physics:Calendar|calendar]], [[Engineering:Contact list|contacts]], and [[Engineering:Calculator|calculator]] and a few games.
* Sending and receiving pictures and videos (by without internet) through [[Multimedia Messaging Service|MMS]], and for short distances with e.g. [[Bluetooth]].
*In Multimedia phones Bluetooth is commonly but important Feature.
* [[Engineering:GPS|GPS]] receivers integrated or connected (i.e. using [[Bluetooth]]) to cell phones, primarily to aid in dispatching emergency responders and road [[Engineering:Tow truck|tow truck]] services. This feature is generally referred to as E911.
* Push to talk, available on some mobile phones, is a feature that allows the user to be heard only while the talk button is held, similar to a walkie-talkie.
* A hardware [[Notification LED|notification LED]] on some phones.

== MOS integrated circuit chips ==
A typical smartphone contains a number of metal–oxide–semiconductor (MOS) [[Engineering:Integrated circuit|integrated circuit]] (IC) chips,<ref name="Kim">{{cite book |last1=Kim |first1=Woonyun |chapter=CMOS power amplifier design for cellular applications: an EDGE/GSM dual-mode quad-band PA in 0.18 μm CMOS |editor-last1=Wang |editor-first1=Hua |editor-last2=Sengupta |editor-first2=Kaushik |title=RF and mm-Wave Power Generation in Silicon |date=2015 |publisher=[[Company:Academic Press|Academic Press]] |isbn=978-0-12-409522-9 |pages=89–90 |chapter-url=https://books.google.com/books?id=PzzLAwAAQBAJ&pg=PA89}}</ref> which in turn contain billions of tiny [[Engineering:MOSFET|MOS field-effect transistors]] (MOSFETs).<ref name="uspto">{{cite web |title=Remarks by Director Iancu at the 2019 International Intellectual Property Conference |url=https://www.uspto.gov/about-us/news-updates/remarks-director-iancu-2019-international-intellectual-property-conference |website=United States Patent and Trademark Office |date=June 10, 2019 |access-date=20 July 2019 |archive-url=https://web.archive.org/web/20191217200937/https://www.uspto.gov/about-us/news-updates/remarks-director-iancu-2019-international-intellectual-property-conference |archive-date=17 December 2019 |url-status=dead }}</ref> A typical smartphone contains the following MOS IC chips.<ref name="Kim"/>

*[[Engineering:Microprocessor|Application processor]] ([[Engineering:CMOS|CMOS]] system-on-a-chip)
*[[Flash memory]] (floating-gate MOS memory)
*Cellular modem ([[Baseband|baseband]] [[Engineering:RF CMOS|RF CMOS]])
*RF transceiver ([[Engineering:RF CMOS|RF CMOS]])
*Phone camera [[Engineering:Image sensor|image sensor]] (CMOS image sensor)
*[[Engineering:Power management integrated circuit|Power management integrated circuit]] ([[Engineering:Power MOSFET|power MOSFET]]s)
*[[Display driver]] (LCD or LED driver)
*Wireless communication chips ([[Wi-Fi]], [[Bluetooth]], GPS receiver)
*[[Engineering:Sound chip|Sound chip]] ([[Audio codec|audio codec]] and power amplifier)
*[[Engineering:Gyroscope|Gyroscope]]
*[[Capacitive sensing|Capacitive]] [[Engineering:Touchscreen|touchscreen]] controller (ASIC and [[Engineering:Digital signal processor|DSP]])<ref name="Kim"/><ref>{{cite journal |last1=Kent |first1=Joel |title=Touchscreen technology basics & a new development |journal=CMOS Emerging Technologies Conference |date=May 2010 |volume=6 |pages=1–13 |url=https://books.google.com/books?id=ekdkWGqw29EC&pg=PA34 |publisher=CMOS Emerging Technologies Research|isbn=9781927500057 }}</ref><ref>{{cite magazine |last1=Ganapati |first1=Priya |title=Finger Fail: Why Most Touchscreens Miss the Point |url=https://www.wired.com/2010/03/touchscreens-smartphones/ |access-date=9 November 2019 |magazine=Wired |date=5 March 2010 |archive-url=https://web.archive.org/web/20140511114207/http://www.wired.com/2010/03/touchscreens-smartphones/ |archive-date=11 May 2014 |url-status=live }}</ref>
*[[Engineering:RF power amplifier|RF power amplifier]] ([[Engineering:LDMOS|LDMOS]])<ref name="Baliga2005">{{cite book |last1=Baliga |first1=Bantval Jayant |title=Silicon RF Power MOSFETS |date=2005 |publisher=[[Company:World Scientific|World Scientific]] |isbn=9789812561213 |pages=1–2 |url=https://books.google.com/books?id=StJpDQAAQBAJ&pg=PA1}}</ref><ref name="Asif">{{cite book |last1=Asif |first1=Saad |title=5G Mobile Communications: Concepts and Technologies |date=2018 |publisher=CRC Press |isbn=9780429881343 |page=134 |url=https://books.google.com/books?id=yg1mDwAAQBAJ&pg=PT134}}</ref><ref name="NXP-LDMOS">{{cite web |title=LDMOS Products and Solutions |url=https://www.nxp.com/products/rf/rf-power/ldmos-products-and-solutions:RF-LDMOS-Products-Sol |website=NXP Semiconductors |access-date=4 December 2019}}</ref>

== User interface ==
[[File:Nokia 3720 buttons.jpeg|thumb|Key pad of a Nokia 3720 ]]
Besides the number keypad and buttons for accepting and declining calls (typically from left to right and coloured green and red respectively), button mobile phones commonly feature two option keys, one to the left and one to the right, and a four-directional [[Engineering:D-pad|D-pad]] which may feature a center button which acts in resemblance to an "Enter" and "OK" button.

A pushable [[Scroll wheel|scroll wheel]] has been implemented in the 1990s on the Nokia 7110.

== Software, applications and services ==
[[File:Phone software.png|thumb|Software-side view of a typical smartphone]]
In early stages, every mobile phone company had its own user interface, which can be considered as "closed" operating system, since there was a minimal configurability. A limited variety of basic applications (usually games, accessories like calculator or conversion tool and so on) was usually included with the phone and those were not available otherwise. Early mobile phones included basic web browser, for reading basic [[Wireless Application Protocol|WAP]] pages. Handhelds ([[Social:Personal digital assistant|Personal digital assistant]]s like [[Engineering:Palm (PDA)|Palm]], running [[Software:Palm OS|Palm OS]]) were more sophisticated and also included more advanced browser and a touch screen (for use with stylus), but these were not broadly used, comparing to standard phones. Other capabilities like Pulling and Pushing Emails or working with calendar were also made more accessible but it usually required physical (and not wireless) [[Data synchronization|Syncing]]. [[Engineering:BlackBerry|BlackBerry]] 850, an email pager, released January 19, 1999, was the first device to integrate Email.

A major step towards a more "open" mobile OS was the symbian [[Software:S60 (software platform)|S60]] OS, that could be expanded by downloading software (written in C++, java or python), and its appearance was more configurable. In July 2008, Apple introduced its App store, which made downloading [[Mobile app|mobile app]]lications more accessible. In October 2008, the [[Engineering:HTC Dream|HTC Dream]] was the first commercially released device to use the Linux-based [[Software:Android (operating system)|Android]] OS, which was purchased and further developed by Google and the Open Handset Alliance to create an open competitor to other major smartphone platforms of the time (Mainly Symbian operating system, BlackBerry OS, and iOS)-The operating system offered a customizable graphical user interface and a notification system showing a list of recent messages pushed from apps.

The most commonly used data application on mobile phones is [[SMS]] text messaging. The first SMS text message was sent from a computer to a mobile phone in 1992 in the UK, while the first person-to-person SMS from phone to phone was sent in Finland in 1993.

The first mobile news service, delivered via SMS, was launched in Finland in 2000. Mobile news services are expanding with many organizations providing "on-demand" news services by SMS. Some also provide "instant" news pushed out by SMS.

Mobile payments were first trialled in Finland in 1998 when two Coca-Cola vending machines in Espoo were enabled to work with SMS payments. Eventually, the idea spread and in 1999 the Philippines launched the first commercial mobile payments systems, on the mobile operators Globe and Smart. Today, mobile payments ranging from [[Finance:Mobile banking|mobile banking]] to mobile credit cards to mobile commerce are very widely used in Asia and Africa, and in selected European markets. Usually, the SMS services utilize [[Engineering:Short code|short code]].

Some network operators have utilized USSD for information, entertainment or finance services (e.g. [[Finance:M-Pesa|M-Pesa]]).

Other non-SMS data services used on mobile phones include mobile music, downloadable logos and pictures, gaming, gambling, adult entertainment and advertising. The first downloadable mobile content was sold to a mobile phone in Finland in 1998, when Radiolinja (now Elisa) introduced the downloadable ringtone service. In 1999, Japanese mobile operator NTT DoCoMo introduced its mobile Internet service, i-Mode, which today is the world's largest mobile Internet service.

Even after the appearance of smartphones, network operators have continued to offer information services, although in some places, those services have become less common.

Power supply 
[[File:Uganda mobile phone charging service.jpg|left|thumb|Mobile phone charging service in Uganda]]
[[File:PSU no load 5 star rating chart.png|thumb|The world's five largest handset makers introduced a new rating system in November 2008 to help consumers more easily identify the most energy-efficient chargers.<ref name="starrating">{{cite web |author=Sheen, James |url=http://www2.electronicproducts.com/PrintArticle.aspx?ArticleURL=FAJH_Energy_Mar2010.html |title=Meeting 30mW Standby in Mobile Phone Chargers |publisher=Electronic Products |date=22 October 2009 |access-date=4 November 2009 |archive-url=https://web.archive.org/web/20100718045236/http://www2.electronicproducts.com/PrintArticle.aspx?ArticleURL=FAJH_Energy_Mar2010.html |archive-date=18 July 2010 |url-status=dead }}</ref>]]

Mobile phones generally obtain power from [[Engineering:Rechargeable battery|rechargeable]] batteries. There are a variety of ways used to charge cell phones, including [[Engineering:USB|USB]], portable batteries, mains power (using an AC adapter), cigarette lighters (using an adapter), or a [[Engineering:Dynamo#Modern|dynamo]]. In 2009, the first wireless charger was released for consumer use.<ref name="goingcellular">[http://goingcellular.com/accessories/powermat-wireless-charger-now-available-441525/ goingcellular.com]&nbsp;— Powermat wireless charger now available</ref> Some manufacturers have been experimenting with alternative power sources, including [[Physics:Solar cell|solar cell]]s.<ref>[http://www.androidphonez.com/charge-mini-solar-panel.html Charge Use Mini Solar Panel | Android Phones<!-- Bot generated title -->].</ref>

Various initiatives, such as the EU Common External Power Supply have been announced to standardize the interface to the charger, and to promote energy efficiency of mains-operated chargers. A star rating system is promoted by some manufacturers, where the most efficient chargers consume less than 0.03 watts and obtain a five-star rating.

===Battery===
Most modern mobile phones use a [[Engineering:Lithium-ion battery|lithium-ion battery]].<ref name="Williams">{{cite journal |last1=Williams |first1=R. K. |last2=Darwish |first2=M. N. |last3=Blanchard |first3=R. A. |last4=Siemieniec |first4=R. |last5=Rutter |first5=P. |last6=Kawaguchi |first6=Y. |title=The Trench Power MOSFET—Part II: Application Specific VDMOS, LDMOS, Packaging, and Reliability |journal=IEEE Transactions on Electron Devices |date=2017 |volume=64 |issue=3 |pages=692–712 |doi=10.1109/TED.2017.2655149 |bibcode=2017ITED...64..692W |s2cid=38550249 |issn=0018-9383}}</ref><ref name="ieee">{{cite web |title=IEEE Medal for Environmental and Safety Technologies Recipients |url=https://www.ieee.org/about/awards/bios/environmental-safety-recipients.html |website=IEEE Medal for Environmental and Safety Technologies |publisher=[[Organization:Institute of Electrical and Electronics Engineers|Institute of Electrical and Electronics Engineers]] |access-date=29 July 2019}}</ref><ref name="Sony-Energy">{{cite web |url=http://www.sonyenergy-devices.co.jp/en/keyword |title=Keywords to understanding Sony Energy Devices – keyword 1991 |website=Sony Energy Devices Corporation |publisher=[[Company:Sony|Sony]] |ref=keyword 1991 |url-status=dead |archive-url=https://web.archive.org/web/20160304224245/http://www.sonyenergy-devices.co.jp/en/keyword/ |archive-date=4 March 2016 |df=dmy-all |access-date=7 December 2019 }}</ref> A popular early mobile phone battery was the [[Chemistry:Nickel–metal hydride battery|nickel metal-hydride]] (NiMH) type, due to its relatively small size and low weight. Lithium-ion batteries later became commonly used, as they are lighter and do not have the [[Engineering:Memory effect#Voltage depression due to over-charging|voltage depression due to long-term over-charging]] that nickel metal-hydride batteries do. Many mobile phone manufacturers use lithium–polymer batteries as opposed to the older lithium-ion, the main advantages being even lower weight and the possibility to make the battery a shape other than strict cuboid.<ref name="batteryguide">{{cite web |title=Cell Phone Battery Guide |url=http://www.funsms.net/cellphone_battery_guide.htm |access-date=16 June 2010 |archive-url=https://web.archive.org/web/20100611221236/http://funsms.net/cellphone_battery_guide.htm |archive-date=11 June 2010 |url-status=dead }}</ref>

== SIM card ==
[[File:Typical cellphone SIM cards.jpg|thumb|Typical mobile phone [[SIM card|SIM card]]]]

GSM mobile phones require a small [[Engineering:Integrated circuit|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 (such as mobile phones and computers). 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 ([[International mobile subscriber identity|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 (PIN for usual use and PUK for unlocking).

SIM cards are available in three standard sizes. The first is the size of a credit card (85.60&nbsp;mm × 53.98&nbsp;mm x 0.76&nbsp;mm, defined by ISO/IEC 7810 as ID-1). The newer, most popular miniature version has the same thickness but a length of 25&nbsp;mm and a width of 15&nbsp;mm (ISO/IEC 7810 ID-000), and has one of its corners truncated (chamfered) to prevent misinsertion. The newest incarnation known as the 3FF or micro-SIM has dimensions of 15&nbsp;mm × 12&nbsp;mm. Most cards of the two smaller sizes are supplied as a full-sized card with the smaller card held in place by a few plastic links; it can easily be broken off to be used in a device that uses the smaller SIM.

The first SIM card was made in 1991 by Munich smart card maker Giesecke & Devrient for the Finnish wireless network operator Radiolinja. Giesecke & Devrient sold the first 300 SIM cards to Elisa (ex. Radiolinja).

Those cell phones that do not use a SIM card have the data programmed into their memory. This data is accessed by using a special digit sequence to access the "NAM" as in "Name" or number programming menu. From there, information can be added, including a new number for the phone, new Service Provider numbers, new emergency numbers, new Authentication Key or A-Key code, and a Preferred Roaming List or PRL. However, to prevent the phone being accidentally disabled or removed from the network, the Service Provider typically locks this data with a Master Subsidiary Lock (MSL). The MSL also locks the device to a particular carrier when it is sold as a [[Finance:Loss leader|loss leader]].

The MSL applies only to the SIM, so once the contract has expired, the MSL still applies to the SIM. The phone, however, is also initially locked by the manufacturer into the Service Provider's MSL. This lock may be disabled so that the phone can use other Service Providers' SIM cards. Most phones purchased outside the U.S. are unlocked phones because there are numerous Service Providers that are close to one another or have overlapping coverage. The cost to unlock a phone varies but is usually very cheap and is sometimes provided by independent phone vendors.

A similar module called a [[Engineering:Removable User Identity Module|Removable User Identity Module]] or RUIM card is present in some CDMA networks, notably in China and Indonesia.

===Multi-card hybrid phones===

A hybrid mobile phone can take more than one SIM card, even of different types. The SIM and RUIM cards can be mixed together, and some phones also support three or four SIMs.<ref>[http://www.trisimphones.com/category/ht-g78 Example of a Triple SIM hybrid phone].</ref><ref>[http://www.trisimphones.com/quad-sim-phones/the-latest-f160-quad-sim-quad-standby-tv-java-phone-with-qwerty-keyboard The Latest F160 Quad Sim Quad Standby TV Java Phone with Qwerty Keyboard | Tri Sim Phones<!-- Bot generated title -->].</ref>

From 2010 onwards they became popular in India and Indonesia and other emerging markets,<ref>{{cite web |url=https://news.yahoo.com/s/nm/20110429/wr_nm/us_handsets |title= Smartphone boom lifts phone market in first quarter - Yahoo! News|website=news.yahoo.com |archive-url=https://web.archive.org/web/20110508150638/http://news.yahoo.com/s/nm/20110429/wr_nm/us_handsets |archive-date=May 8, 2011}}</ref> attributed to the desire to obtain the lowest on-net calling rate.  In Q3 2011, [[Company:Nokia|Nokia]] shipped 18 million of its low cost dual SIM phone range in an attempt to make up lost ground in the higher end smartphone market.<ref>{{cite web |url=http://www.ft.com/intl/cms/s/0/11bbf530-fb11-11e0-bebe-00144feab49a.html#axzz1bTfJxgTz |title=Nokia boosted by sales of cheap handsets |date=October 20, 2011}}</ref>

== [[Engineering:Display size|Display]] ==
Mobile phones have a [[Engineering:Display device|display device]], some of which are also touch screens. The screen size varies greatly by model and is usually specified either as width and height in pixels or the diagonal measured in [[Inch|inch]]es.

Some phones have more than one display, for example the [[Engineering:Kyocera Echo|Kyocera Echo]], an [[Software:Android (operating system)|Android]] [[Engineering:Smartphone|smartphone]] with a dual 3.5&nbsp;inch screen. The screens can also be combined into a single 4.7&nbsp;inch [[Engineering:Tablet computer|tablet style computer]].<ref>[http://www.pcworld.com/article/225179/the_kyocera_echo_the_phone_that_wants_to_be_your_tablet.html Kyocera Echo Phone Review | PCWorld<!-- Bot generated title -->].</ref>

== Central processing unit ==
Mobile phones have [[Central processing unit|central processing unit]]s (CPUs), similar to those in computers, but optimised to operate in low power environments. In smartphones, the CPU is typically integrated in a system-on-a-chip (SoC) application [[Engineering:Microprocessor|processor]].

Mobile CPU performance depends not only on the clock rate (generally given in multiples of [[Hertz|hertz]])<ref>{{cite web
 | title = CPU Frequency
 | work = CPU World Glossary
 | publisher = CPU World
 | date = 25 March 2008
 | url = http://www.cpu-world.com/Glossary/C/CPU_Frequency.html
 | access-date =1 January 2010 }}</ref> but also the [[Memory hierarchy|memory hierarchy]] also greatly affects overall performance. Because of these problems, the performance of mobile phone CPUs is often more appropriately given by scores derived from various standardized tests to measure the real effective performance in commonly used applications.

== Miscellaneous features ==
Other features that may be found on mobile phones include GPS navigation, music (MP3) and video ([[MP4]]) playback, [[Physics:Radio Data System|RDS]] radio receiver, built-in projector, vibration and other "silent" ring options, alarms, memo recording, [[Social:Personal digital assistant|personal digital assistant]] functions, ability to watch streaming video, video download, video calling, built-in cameras (1.0+ Mpx) and [[Engineering:Camcorder|camcorder]]s (video recording), with [[Engineering:Autofocus|autofocus]]{{dubious|date=December 2011}} and flash, [[Engineering:Ringtone|ringtone]]s, games, PTT, [[Memory card reader|memory card reader]] (SD), [[Engineering:USB|USB]] (2.0), dual line support, infrared, [[Bluetooth]] (2.0) and WiFi connectivity, NFC,  [[Social:Instant messaging|instant messaging]], Internet e-mail and [[Software:Web browser|browsing]] and serving as a wireless modem.
 
The first smartphone was the [[Engineering:Nokia 9000 Communicator|Nokia 9000 Communicator]] {{dubious|date=January 2015}} in 1996 which added [[Social:Personal digital assistant|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 smartphone has evolved, and what was a high-end smartphone five years ago, is a standard phone today.

Several phone series have been introduced to address a given market segment, such as the RIM [[Engineering:BlackBerry|BlackBerry]] focusing on enterprise/corporate customer email needs; the SonyEricsson Walkman series of musicphones and Cybershot series of cameraphones; the Nokia Nseries of multimedia phones, the [[Engineering:Palm Pre|Palm Pre]] the [[Engineering:HTC Dream|HTC Dream]] and the Apple [[Engineering:IPhone|iPhone]].

[[Company:Nokia|Nokia]] and the University of Cambridge demonstrated a bendable cell phone called the Morph.<ref>Reardon, Marguerite. [http://news.cnet.com/8301-10784_3-9878005-7.html "Nokia demos bendable cell phone"]. CNET News, February 25, 2008. Retrieved 20 July 2009.</ref> Some phones have an electromechanical [[Engineering:Transducer|transducer]] on the back which changes the electrical voice signal into mechanical vibrations. The vibrations flow through the cheek bones or forehead allowing the user to hear the conversation. This is useful in the noisy situations or if the user is hard of hearing.<ref>[http://www.ieumart.com/mito-228-unique-handphone-can-hear-with-the-cheek.html Mito 228: Unique Handphone, Can Hear with the cheek] {{Webarchive|url=https://web.archive.org/web/20111017004856/http://www.ieumart.com/mito-228-unique-handphone-can-hear-with-the-cheek.html |date=2011-10-17 }}, IeuMart.com</ref>

As of 2018, there are smartphones that offer reverse wireless charging.<ref>{{Cite web|url=https://wccftech.com/huawei-mate-20-pro-wirelessly-charge-iphones/|title=Huawei Takes a Jab at Apple - Says Its Mate 20 Pro Will Be Able to Charge iPhones Wirelessly|first=Omar|last=Sohail|date=October 16, 2018}}</ref>

== Multi-mode and multi-band mobile phones ==

Most mobile phone networks are digital and use the GSM, CDMA or iDEN standard which operate at [[Engineering:Radio frequency|various radio frequencies]].  These phones can only be used with a service plan from the same company. For example, a Verizon phone cannot be used with a T-Mobile service, and vica versa.

A multi-mode phone operates across different standards whereas a multi-band phone (also known more specifically as dual, tri or quad band) mobile phone is a phone which is designed to work on more than one radio frequency. Some multi-mode phones can operate on analog networks as well (for example, dual band, tri-mode: AMPS 800 / CDMA 800 / CDMA 1900).

For a GSM phone, dual-band usually means 850 / 1900&nbsp;MHz in the {{wipe|United States}} and {{wipe|Canada}}, 900 / 1800&nbsp;MHz in [[Earth:Europe|Europe]] and most other countries. Tri-band means 850 / 1800 / 1900&nbsp;MHz or 900 / 1800 / 1900&nbsp;MHz. Quad-band means 850 / 900 / 1800 / 1900&nbsp;MHz, also called a world phone, since it can work on any GSM network.

Multi-band phones have been valuable to enable roaming whereas multi-mode phones helped to introduce WCDMA features without customers having to give up the wide coverage of GSM. Almost every single true [[3G|3G]] phone sold is actually a WCDMA/GSM ''dual-mode'' mobile. This is also true of 2.75G phones such as those based on CDMA-2000 or EDGE.

=== Challenges in producing multi-mode phones ===
The special challenge involved in producing a multi-mode mobile is in finding ways to share the components between the different standards. Obviously, the phone keypad and display should be shared, otherwise it would be hard to treat as one phone. Beyond that, though, there are challenges at each level of integration. How difficult these challenges are depends on the differences between systems. When talking about IS-95/GSM multi-mode phones, for example, or AMPS/IS-95 phones, the base band processing is very different from system to system. This leads to real difficulties in component integration and so to larger phones.

An interesting special case of multi-mode phones is the WCDMA/GSM phone. The radio interfaces are very different from each other, but mobile to core network messaging has strong similarities, meaning that software sharing is quite easy. Probably more importantly, the WCDMA air interface has been designed with GSM compatibility in mind. It has a special mode of operation, known as punctured mode, in which, instead of transmitting continuously, the mobile is able to stop sending for a short period and try searching for GSM carriers in the area. This mode allows for safe inter-frequency handovers with channel measurements which can only be approximated using "pilot signals" in other CDMA based systems.

A final interesting case is that of mobiles covering the DS-WCDMA and [[Engineering:Multi-carrier code-division multiple access|MC-CDMA]] [[3G|3G]] variants of the CDMA-2000 protocol. Initially, the [[Chip rate|chip rate]] of these phones was incompatible. As part of the negotiations related to [[Social:Patent|patent]]s, it was agreed to use compatible chip rates. This should mean that, despite the fact that the air and system interfaces are quite different, even on a philosophical level, much of the hardware for each system inside a phone should be common with differences being mostly confined to software.

==Data communications==

Mobile phones are now heavily used for data communications. such as SMS messages, browsing mobile web sites, and even streaming audio and video files. The main limiting factors are the size of the screen, lack of a keyboard, processing power and connection speed. Most cellphones, which supports data communications, can be used as wireless modems (via cable or bluetooth), to connect computer to internet. Such access method is slow and expensive, but it can be available in very remote areas.

With newer smartphones, screen resolution and processing power has become bigger and better. Some new phone [[Central processing unit|CPU]]s run at over 1&nbsp;GHz. Many complex programs are now available for the various smartphones, such as [[Software:Symbian|Symbian]] and [[Software:Windows Mobile|Windows Mobile]].

Connection speed is based on network support. Originally data transfers over GSM networks were possible only over CSD (circuit switched data), it has bandwidth of 9600 bit/s and usually is billed by connection time (from network point of view, it does not differ much from voice call). Later, there were introduced improved version of CSD - HSCSD (high speed CSD), it could use multiple time slots for downlink, improving speed. Maximum speed for HSCSD is ~42 kbit/s, it also is billed by time. Later was introduced [[General Packet Radio Service|GPRS]] (general packet radio service), which operates on completely different principle. It also can use multiple time slots for transfer, but it does not tie up radio resources, when not transferring data (as opposed to CSD and like). GPRS usually is prioritized under voice and CSD, so latencies are large and variable. Later, GPRS was upgraded to EDGE, which differs mainly by radio modulation, squeezing more data capacity in same radio bandwidth. GPRS and EDGE usually are billed by data traffic volume. Some phones also feature full Qwerty keyboards, such as the LG enV.

As of April 2006, several models, such as the [[Engineering:Nokia 6680|Nokia 6680]], support [[3G|3G]] communications. Such phones have access to the Web via a free download of the [[Software:Opera (web browser)|Opera]] web browser. [[Company:Verizon Wireless|Verizon Wireless]] models come with [[Software:Internet Explorer|Internet Explorer]] pre-loaded onto the phone.

==Vulnerability to viruses==
{{main|Mobile virus}}

As more complex features are added to phones, they become more vulnerable to viruses which exploit weaknesses in these features.  Even text messages can be used in attacks by [[Computer worm|worms]] and [[Biology:Virus|virus]]es.<ref>{{Cite web|date=2005-10-04|title=How Cell-phone Viruses Work|url=https://electronics.howstuffworks.com/cell-phone-virus.htm|access-date=2021-01-21|website=HowStuffWorks|language=en}}</ref> Advanced phones capable of e-mail can be susceptible to viruses that can multiply by sending messages through a phone's address book.{{Citation needed|date=July 2007}} In some phone models, the USSD was exploited for inducing a [[Factory reset|factory reset]],<ref>{{Cite web|url=https://www.engadget.com/2012/09/25/dirty-ussd-code-samsung-hack-wipe/|title='Dirty USSD' code could automatically wipe your Samsung TouchWiz device (updated)|website=Engadget}}</ref> resulting in clearing the data and resetting the user settings.

A virus may allow unauthorized users to access a phone to find [[Password|password]]s or corporate [[Data|data]] stored on the device. Moreover, they can be used to commandeer the phone to make calls or send messages at the owner's expense.{{Citation needed|date=July 2007}}

Mobile phones used to have proprietary [[Operating system|operating system]] unique only to the manufacturer which had the beneficial effect of making it harder to design a mass attack. However, the rise of software platforms and operating systems shared by many manufacturers such as [[Java (programming language)|Java]], [[Company:Microsoft|Microsoft]] operating systems, [[Software:Linux|Linux]], or Symbian OS, may increase the spread of viruses in the future.

[[Bluetooth]] is a feature now found in many higher-end phones, and the virus Caribe hijacked this function, making Bluetooth phones infect other Bluetooth phones running the Symbian OS. In early November 2004, several web sites began offering a specific piece of [[Software|software]] promising [[Engineering:Ringtone|ringtone]]s and [[Screensaver|screensaver]]s for certain phones. Those who downloaded the software found that it turned each [[Icon (computing)|icon]] on the phone's screen into a skull-and-crossbones and disabled their phones, so they could no longer send or receive text messages or access contact lists or [[Physics:Calendar|calendar]]s. The virus has since been dubbed "Skulls" by security experts. The Commwarrior-A virus was identified in March 2005, and it attempts to replicate itself through [[Multimedia Messaging Service|MMS]] to others on the phone's contact list. Like Cabir, Commwarrior-A also tries to communicate via Bluetooth wireless connections with other devices, which can eventually lead to draining the battery. The virus requires user intervention for propagation however.

Bluetooth phones are also subject to [[Bluejacking|bluejacking]], which although not a virus, does allow for the transmission of unwanted messages from anonymous Bluetooth users.

== Cameras ==

Most current phones also have a built-in [[Engineering:Digital camera|digital camera]] (see [[Engineering:Camera phone|camera phone]]), that can have resolutions as high as 108M pixels.
<ref>{{Cite web|url=https://m.gsmarena.com/oppo_reno_10x_zoom-9654.php|title=Oppo Reno 10x zoom - Full phone specifications|website=m.gsmarena.com}}</ref> This gives rise to some concern about [[Privacy|privacy]], in view of possible [[Medicine:Voyeurism|voyeurism]], for example in [[Earth:Swimming pool|swimming pool]]s. {{wipe|South Korea}} has ordered manufacturers to ensure that all new handsets emit a beep whenever a picture is taken.

Sound recording and [[Engineering:Digital video recorder|video recording]] is often also possible. Most people do not walk around with a video camera, but do carry a phone. The arrival of video camera phones is transforming the availability of video to consumers, and helps fuel [[Social:Citizen journalism|citizen journalism]].

==See also==
* [[Software:Mobile game|Mobile game]]
* [[Engineering:Ringtone|Ringtone]]
* [[Engineering:Smartphone|Smartphone]]
* Mobile phone form factor
* Wallpaper

== References ==
<References/>

{{Mobile phones}}

[[Category:Software features|Mobile phone]]
[[Category:Mobile phones]]

{{Sourceattribution|Mobile phone features|1}}