Mobile phone features

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Hardware-side view of a typical smartphone Phone hardware.png
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 feature phones, and offer basic telephony.[ clarification needed ] 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.

Contents

The common components found on all phones are:

All mobile phones are designed to work on cellular networks 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:

MOS integrated circuit chips

A typical smartphone contains a number of metal–oxide–semiconductor (MOS) integrated circuit (IC) chips, [1] which in turn contain billions of tiny MOS field-effect transistors (MOSFETs). [2] A typical smartphone contains the following MOS IC chips. [1]

User interface

Key pad of a Nokia 3720 Nokia 3720 buttons.jpeg
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 D-pad which may feature a center button which acts in resemblance to an "Enter" and "OK" button.

A pushable scroll wheel has been implemented in the 1990s on the Nokia 7110.

Software, applications and services

Software-side view of a typical smartphone Phone software.png
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 WAP pages. Handhelds (Personal digital assistants like Palm, running 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) Syncing. 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 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 applications more accessible. In October 2008, the HTC Dream was the first commercially released device to use the Linux-based 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 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 short code.

Some network operators have utilized USSD for information, entertainment or finance services (e.g. 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

Mobile phone charging service in Uganda Uganda mobile phone charging service.jpg
Mobile phone charging service in Uganda
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. PSU no load 5 star rating chart.png
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.

Mobile phones generally obtain power from rechargeable batteries. There are a variety of ways used to charge cell phones, including USB, portable batteries, mains power (using an AC adapter), cigarette lighters (using an adapter), or a dynamo. In 2009, the first wireless charger was released for consumer use. [9] Some manufacturers have been experimenting with alternative power sources, including solar cells. [10]

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 lithium-ion battery. [11] [12] [13] A popular early mobile phone battery was the 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 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. [14]

SIM card

Typical mobile phone SIM card Typical cellphone SIM cards.jpg
Typical mobile phone SIM card

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 (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 (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 mm × 53.98 mm x 0.76 mm, defined by ISO/IEC 7810 as ID-1). The newer, most popular miniature version has the same thickness but a length of 25 mm and a width of 15 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 mm × 12 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 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 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. [15] [16]

From 2010 onwards they became popular in India and Indonesia and other emerging markets, [17] attributed to the desire to obtain the lowest on-net calling rate. In Q3 2011, 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. [18]

Display

Mobile phones have a 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 inches.

Some phones have more than one display, for example the Kyocera Echo, an Android smartphone with a dual 3.5 inch screen. The screens can also be combined into a single 4.7 inch tablet style computer. [19]

Central processing unit

Mobile phones have central processing units (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 processor.

Mobile CPU performance depends not only on the clock rate (generally given in multiples of hertz) [20] but also the 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, RDS radio receiver, built-in projector, vibration and other "silent" ring options, alarms, memo recording, personal digital assistant functions, ability to watch streaming video, video download, video calling, built-in cameras (1.0+ Mpx) and camcorders (video recording), with autofocus [ dubious ] and flash, ringtones, games, PTT, memory card reader (SD), USB (2.0), dual line support, infrared, Bluetooth (2.0) and WiFi connectivity, NFC, instant messaging, Internet e-mail and browsing and serving as a wireless modem.

The first smartphone was the Nokia 9000 Communicator [ dubious ] 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 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 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 Palm Pre the HTC Dream and the Apple iPhone.

Nokia and the University of Cambridge demonstrated a bendable cell phone called the Morph. [21] Some phones have an electromechanical 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. [22]

As of 2018, there are smartphones that offer reverse wireless charging. [23]

Multi-mode and multi-band mobile phones

Most mobile phone networks are digital and use the GSM, CDMA or iDEN standard which operate at 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 MHz in the United States and Canada, 900 / 1800 MHz in Europe and most other countries. Tri-band means 850 / 1800 / 1900 MHz or 900 / 1800 / 1900 MHz. Quad-band means 850 / 900 / 1800 / 1900 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 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 MC-CDMA 3G variants of the CDMA-2000 protocol. Initially, the chip rate of these phones was incompatible. As part of the negotiations related to patents, 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 CPUs run at over 1 GHz. Many complex programs are now available for the various smartphones, such as Symbian and 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 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 Nokia 6680, support 3G communications. Such phones have access to the Web via a free download of the Opera web browser. Verizon Wireless models come with Internet Explorer pre-loaded onto the phone.

Vulnerability to viruses

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 worms and viruses. [24] 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 ] In some phone models, the USSD was exploited for inducing a factory reset, [25] resulting in clearing the data and resetting the user settings.

A virus may allow unauthorized users to access a phone to find passwords or corporate 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 ]

Mobile phones used to have proprietary 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, Microsoft operating systems, 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 promising ringtones and screensavers for certain phones. Those who downloaded the software found that it turned each 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 calendars. 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 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, 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 digital camera (see camera phone), that can have resolutions as high as 108M pixels. [26] This gives rise to some concern about privacy, in view of possible voyeurism, for example in swimming pools. South Korea has ordered manufacturers to ensure that all new handsets emit a beep whenever a picture is taken.

Sound recording and 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 citizen journalism.

See also

Related Research Articles

The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP, UMTS is a component of the International Telecommunication Union IMT-2000 standard set and compares with the CDMA2000 standard set for networks based on the competing cdmaOne technology. UMTS uses wideband code-division multiple access (W-CDMA) radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators.

<span class="mw-page-title-main">Smartphone</span> Handheld mobile device

A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, which facilitate wider software, internet, and multimedia functionality, alongside core phone functions such as voice calls and text messaging. Smartphones typically contain a number of metal–oxide–semiconductor (MOS) integrated circuit (IC) chips, include various sensors that can be leveraged by pre-included and third-party software, and support wireless communications protocols. More recently, smartphone manufacturers have begun to integrate satellite messaging connectivity and satellite emergency services into devices for use in remote regions, where there is no reliable cellular network.

<span class="mw-page-title-main">SIM card</span> Integrated circuit card for a mobile device

A SIM card is an integrated circuit (IC) intended to securely store the international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers on mobile telephony devices. Technically the actual physical card is known as a universal integrated circuit card (UICC); this smart card is usually made of PVC with embedded contacts and semiconductors, with the SIM as its primary component. In practise the term "SIM card" refers to the entire unit and not simply the IC.

<span class="mw-page-title-main">Nokia 6620</span> 2005 smartphone model

The 6620 is a smartphone created by Nokia, announced in 2005, running on Series 60 2nd Edition and the Symbian operating system. It was the first EDGE-capable phone for the Americas' market.

<span class="mw-page-title-main">Nokia 6230</span> Cell phone model

The Nokia 6230 is a mobile phone based on the Nokia Series 40 platform. It was announced on 28 October 2003 and released in February 2004.

<span class="mw-page-title-main">Nokia 6630</span> Smartphone

The Nokia 6630 is a 3G smartphone announced by Nokia on 14 June 2004 and released in November. It runs on Symbian OS 8.0a. Codenamed Charlie during development, it is an evolution of the 6600 and 6620 smartphones, supporting tri-band GSM.

<span class="mw-page-title-main">Nokia 8210</span> Cell phone model

Nokia 8210 is a mobile phone by Nokia, announced on 8 October 1999 in Paris. At the time, it was the smallest, lightest Nokia mobile phone on the market, thus its selling point was based on its design and customization, with removable Xpress-on covers. Six differently coloured Xpress-on covers are available, as well as many third-party ones.

Proximity marketing is the localized wireless distribution of advertising content associated with a particular place. Transmissions can be received by individuals in that location who wish to receive them and have the necessary equipment to do so.

The Motorola Q is a Windows Mobile smartphone first announced in the Summer of 2005 as a thin device with similar styling to Motorola's immensely popular RAZR. Motorola in a partnership with Verizon Wireless released the Q on May 31, 2006. A version for Sprint was released early in January 2007 and one for Amp'd Mobile in April 2007.

<span class="mw-page-title-main">HTC Universal</span>

The HTC Universal is a Windows Mobile 5.0 Pocket PC PDA manufactured by High Tech Computer Corporation. It was the first 3G/UMTS-enabled Pocket PC PDA with a telecommunications function, and also the first to come with Windows Mobile 5.0 pre-installed.

Motorola Rizr is a series of slide mobile phones from Motorola, and is one of the series in the 4LTR line. The first model was released in late 2006. It is a sliding phone, where the numeric keys are hidden beneath the screen of the phone when closed.

<span class="mw-page-title-main">Nokia N93i</span>

The Nokia N93i is a smartphone produced by Nokia, announced on 8 January 2007 and released the same month. It is part of the Nseries line and is a redesign of the Nokia N93. The N93i runs on Symbian OS version 9.1, with the S60 3rd Edition user interface. Like the N93, it is a clamshell and swivel design with a camera and landscape position.

The Nokia 6000 series or Classic Business series is range of mobile phones marketed by Nokia. This family of phones is notable for their conservative, unisex designs, making the family popular with business users.

<span class="mw-page-title-main">Nokia 5300</span> Cell phone model

Nokia 5300 XpressMusic is a slider mobile phone by Nokia, part of the XpressMusic range. It was introduced on 26 September 2006 and released at the end of that year. It runs on Nokia Series 40 3rd Edition FP2.

<span class="mw-page-title-main">Nokia E71</span> Smartphone model

The Nokia E71 is a smartphone introduced in May 2008 from the Eseries range with a QWERTY keyboard targeting business users worldwide. It runs on Symbian OS v9.2, with a Series 60 3rd Edition, second generation Feature Pack 1. The Nokia E71 succeeded the Nokia E61/61i models, building on the base design and form factor but enhancing on the feature set.

<span class="mw-page-title-main">Mobile phone</span> Portable device to make telephone calls using a radio link

A mobile 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 switched telephone network (PSTN). Modern mobile telephone services use a cellular network architecture and, therefore, mobile telephones are called cellular telephones or cell phones in North America. In addition to telephony, digital mobile phones support a variety of other services, such as text messaging, multimedia messagIng, email, Internet access, short-range wireless communications, satellite access, business applications, video games and digital photography. Mobile phones offering only those capabilities are known as feature phones; mobile phones which offer greatly advanced computing capabilities are referred to as smartphones.

<span class="mw-page-title-main">Nokia N900</span> Smartphone model

The Nokia N900 is a smartphone made by Nokia. It supersedes the Nokia N810. Its default operating system, Maemo 5, is a Linux-based OS originally developed for the Nokia 770 Internet Tablet. It is the first Nokia device based upon the Texas Instruments OMAP3 microprocessor with the ARM Cortex-A8 core. Unlike the three Nokia Internet tablets preceding it, the Nokia N900 is the first Maemo device to include phone functionality.

<span class="mw-page-title-main">Nokia 2730 classic</span> 2009 cell phone model

The Nokia 2730 classic is a Nokia Quad-band GSM/UMTS 3G cell phone that includes a camera, FM radio, Bluetooth, music and video player, as well as several internet-based applications.

<span class="mw-page-title-main">Mobile security</span> Security risk and prevention for mobile devices

Mobile security, or mobile device security, is the protection of smartphones, tablets, and laptops from threats associated with wireless computing. It has become increasingly important in mobile computing. The security of personal and business information now stored on smartphones is of particular concern.

<span class="mw-page-title-main">Nokia Asha 310</span>

The Nokia Asha 310, also known as the Nokia Asha 3010 or the Nokia ASHA 310 RM-911, was released in March 2013. It is the first in the line of the Asha range of phones to have dual subscriber identity module (SIM) slots and Wi-Fi connectivity. It was a reinvention of the Asha range to remain competitive with new Android devices. It cost $102.00 at its launch date. It has a touchscreen, comes with either a 2 or 4 GB micro SD card, and has 64 MB of RAM, a 2 MP camera and a battery that can last up to 600 hours in standby mode. The phone can play music for up to 54 hours or video for up to 9.5 hours, and has a maximum of 17 hours talk time (2G).

References

  1. 1 2 3 Kim, Woonyun (2015). "CMOS power amplifier design for cellular applications: an EDGE/GSM dual-mode quad-band PA in 0.18 μm CMOS". In Wang, Hua; Sengupta, Kaushik (eds.). RF and mm-Wave Power Generation in Silicon. Academic Press. pp. 89–90. ISBN   978-0-12-409522-9.
  2. "Remarks by Director Iancu at the 2019 International Intellectual Property Conference". United States Patent and Trademark Office . June 10, 2019. Archived from the original on 17 December 2019. Retrieved 20 July 2019.
  3. Kent, Joel (May 2010). "Touchscreen technology basics & a new development". CMOS Emerging Technologies Conference. CMOS Emerging Technologies Research. 6: 1–13. ISBN   9781927500057.
  4. Ganapati, Priya (5 March 2010). "Finger Fail: Why Most Touchscreens Miss the Point". Wired . Archived from the original on 11 May 2014. Retrieved 9 November 2019.
  5. Baliga, Bantval Jayant (2005). Silicon RF Power MOSFETS. World Scientific. pp. 1–2. ISBN   9789812561213.
  6. Asif, Saad (2018). 5G Mobile Communications: Concepts and Technologies. CRC Press. p. 134. ISBN   9780429881343.
  7. "LDMOS Products and Solutions". NXP Semiconductors . Retrieved 4 December 2019.
  8. Sheen, James (22 October 2009). "Meeting 30mW Standby in Mobile Phone Chargers". Electronic Products. Archived from the original on 18 July 2010. Retrieved 4 November 2009.
  9. goingcellular.com  — Powermat wireless charger now available
  10. Charge Use Mini Solar Panel | Android Phones.
  11. Williams, R. K.; Darwish, M. N.; Blanchard, R. A.; Siemieniec, R.; Rutter, P.; Kawaguchi, Y. (2017). "The Trench Power MOSFET—Part II: Application Specific VDMOS, LDMOS, Packaging, and Reliability". IEEE Transactions on Electron Devices. 64 (3): 692–712. Bibcode:2017ITED...64..692W. doi:10.1109/TED.2017.2655149. ISSN   0018-9383. S2CID   38550249.
  12. "IEEE Medal for Environmental and Safety Technologies Recipients". IEEE Medal for Environmental and Safety Technologies . Institute of Electrical and Electronics Engineers . Retrieved 29 July 2019.
  13. "Keywords to understanding Sony Energy Devices – keyword 1991". Sony Energy Devices Corporation . Sony. Archived from the original on 4 March 2016. Retrieved 7 December 2019.
  14. "Cell Phone Battery Guide". Archived from the original on 11 June 2010. Retrieved 16 June 2010.
  15. Example of a Triple SIM hybrid phone.
  16. The Latest F160 Quad Sim Quad Standby TV Java Phone with Qwerty Keyboard | Tri Sim Phones.
  17. "Smartphone boom lifts phone market in first quarter - Yahoo! News". news.yahoo.com. Archived from the original on May 8, 2011.
  18. "Nokia boosted by sales of cheap handsets" . October 20, 2011. Archived from the original on 2022-12-11.
  19. Kyocera Echo Phone Review | PCWorld.
  20. "CPU Frequency". CPU World Glossary. CPU World. 25 March 2008. Retrieved 1 January 2010.
  21. Reardon, Marguerite. "Nokia demos bendable cell phone". CNET News, February 25, 2008. Retrieved 20 July 2009.
  22. Mito 228: Unique Handphone, Can Hear with the cheek Archived 2011-10-17 at the Wayback Machine , IeuMart.com
  23. Sohail, Omar (October 16, 2018). "Huawei Takes a Jab at Apple - Says Its Mate 20 Pro Will Be Able to Charge iPhones Wirelessly".
  24. "How Cell-phone Viruses Work". HowStuffWorks. 2005-10-04. Retrieved 2021-01-21.
  25. "'Dirty USSD' code could automatically wipe your Samsung TouchWiz device (updated)". Engadget.
  26. "Oppo Reno 10x zoom - Full phone specifications". m.gsmarena.com.