Hardware-side view of a typical smartphone
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
, and offer basic telephony.
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 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
are also found in smartphones.
mobile phone services
to allow users to make calls and send text messages.
phones use a
to allow an account to be swapped among devices. Some
devices also have a similar card called a
Individual GSM, WCDMA, iDEN and some satellite phone devices are uniquely identified by an
International Mobile Equipment Identity
All mobile phones are designed to work on
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:
Software, applications and services
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
pages. Handhelds (
Personal digital assistants
) 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)
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
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
, which made downloading
more accessible. In October 2008, the
was the first commercially released device to use the Linux-based
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
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.
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
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
Some network operators have utilized
for information, entertainment or finance services (e.g.
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,
, 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.
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.
Mobile phones generally obtain power from
batteries. There are a variety of ways used to charge cell phones, including
, portable batteries, mains power (using an
), cigarette lighters (using an adapter), or a
. In 2009, the first wireless charger was released for consumer use.
Some manufacturers have been experimenting with alternative power sources, including
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.
A popular early mobile phone battery was the
(NiMH) type, due to its relatively small size and low weight.
batteries are also 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
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.
mobile phones require a small
called a Subscriber Identity Module or
, 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 (
), 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
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
. 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
the device to a particular carrier when it is sold as a
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.
From 2010 onwards they became popular in India and Indonesia and other emerging markets,
attributed to the desire to obtain the lowest on-net calling rate. In Q3 2011,
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.
Mobile phones have a
, some of which are also
varies greatly by model and is usually specified either as width and height in pixels or the diagonal measured in
Some mobiles have more than one display, for example the
with a dual 3.5 inch screen. The screens can also be combined into a single 4.7 inch
tablet style computer
Central processing unit
Mobile phones have
central processing units
(CPUs), similar to those in computers, but optimised to operate in low power environments.
Mobile CPU performance depends not only on the clock rate (generally given in multiples of
but also the
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.
Other features that may be found on mobile phones include
, music (MP3) and video (
radio receiver, built-in projector, vibration and other “silent” ring options, alarms, memo recording,
personal digital assistant
functions, ability to watch
, video download,
, built-in cameras (1.0+
(video recording), with
memory card reader
(2.0), dual line support, infrared,
, Internet e-mail and
and serving as a
The first smartphone was the
Nokia 9000 Communicator
in 1996 which added
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
focusing on enterprise/corporate customer email needs; the SonyEricsson Walkman series of musicphones and Cybershot series of cameraphones; the
of multimedia phones, the
and the Apple
and the University of Cambridge demonstrated a bendable cell phone called the
Some phones have an electromechanical
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.
Multi-mode and multi-band mobile phones
Most mobile phone networks are digital and use the
standard which operate at
various radio frequencies
. These phones can only be used with a service plan from the same company. For example, a
phone cannot be used with a
service, and vica versa.
A multi-mode phone operates across different standards whereas a multi-band phone (also known more specifically as
) mobile phone is a phone which is designed to work on more than one
. Some multi-mode phones can operate on analog networks as well (for example, dual band, tri-mode:
800 / CDMA 1900).
For a GSM phone, dual-band usually means 850 / 1900 MHz in the
, 900 / 1800 MHz in
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
whereas multi-mode phones helped to introduce
features without customers having to give up the wide coverage of
. Almost every single true
phone sold is actually a WCDMA/GSM
mobile. This is also true of
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
A final interesting case is that of mobiles covering the
variants of the
protocol. Initially, the
of these phones was incompatible. As part of the negotiations related to
, 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.
Mobile phones are now heavily used for data communications. such as
messages, browsing mobile
, 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
(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.
, screen resolution and processing power has become bigger and better. Some new phone
run at over 1 GHz. Many complex programs are now available for the various smartphones, such as
Connection speed is based on network support. Originally data transfers over GSM networks were possible only over
(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 –
(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), 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
, 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
, such as the
As of April 2006, several models, such as the
communications. Such phones have access to the Web via a free download of the
models come with
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
can be used in attacks by
Advanced phones capable of
can be susceptible to viruses that can multiply by sending messages through a phone’s address book.
In some phone models, the
was exploited for inducing a
resulting in clearing the data and resetting the user settings.
A virus may allow unauthorized users to access a phone to find
stored on the device. Moreover, they can be used to commandeer the phone to make calls or send messages at the owner’s expense.
Mobile phones used to have proprietary
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
, may increase the spread of viruses in the future.
is a feature now found in many higher-end phones, and the virus
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
for certain phones. Those who downloaded the software found that it turned each
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
. The virus has since been dubbed ”
” by security experts. The
virus was identified in March 2005, and it attempts to replicate itself through
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
, which although not a virus, does allow for the transmission of unwanted messages from anonymous Bluetooth users.
Most current phones also have a built-in
), that can have resolutions as high as 38M pixels.
This gives rise to some concern about
, in view of possible
, for example in
has ordered manufacturers to ensure that all new handsets emit a beep whenever a picture is taken.
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