what is 2g,3g,4g,and 5g network

The “G” stands for Generation, as in the next generation of wireless technologies. Each generation is supposedly faster, more secure and more reliable. The reliability factor is the hardest obstacle to overcome. 1G was not used to identify wireless technology until 2G, or the second generation, was released. That was a major jump in the technology when the wireless networks went from analog to digital. It’s all uphill from there. 3G came along and offered faster data transfer speeds, at least 200 kilobits per second, for multi-media use and was a long time standard for wireless transmissions regardless of what you heard on all those commercials when they told you you were getting a 4G connection It is still a challenge to get a true 4G connection, which promises upwards of a 1Gps, Gigabit per second, transfer rate if you are standing still and in the perfect spot. 4G LTE comes very close to closing this gap. True 4G on a wide spread basis may not be available until the next generation arrives. 5G?

 What are the Standards of the G’s
 1G or (1-G) refers to the first generation of wireless telephone technology (mobile telecommunications). These are the analog telecommunications standards that were introduced in 1979 and the early to mid-1980s and continued until being replaced by 2G digital telecommunications. The main difference between the two mobile telephone systems (1G and 2G), is that the radio signals used by 1G network are analog, while 2G networks are digital.

 2G – The second generation of cell phone transmission. A few more features were added to the menu such as simple text messaging.2G (or 2-G) provides three primary benefits over their predecessors: phone conversations are digitally encrypted; 2G systems are significantly more efficient on the spectrum allowing for far greater mobile phone penetration levels; and 2G introduced data services for mobile, starting with SMS (Short Message Service) plain text-based messages. 2G technologies enable the various mobile phone networks to provide the services such as text messages, picture messages and MMS (Multimedia Message Service). It has 3 main services: Bearer services is one of them which is also known as data services.

 3G – This generation set the standards for most of the wireless technology we have come to know and love. Web browsing, email, video downloading, picture sharing and other Smartphone technology were introduced in the third generation. 3G should be capable of handling around 2 Megabits per second.3.5G is a grouping of disparate mobile telephony and data technologies designed to provide better performance than 3G systems, as an interim step towards the deployment of full 4G capability. The technology includes:

• High-Speed Downlink Packet Access
• 3GPP Long Term Evolution, precursor of LTE Advanced
• Evolved HSPA 

4G – 4G provides, in addition to the usual voice and other services of 3G, mobile broadband Internet access, for example to laptops with wireless modems, to smartphones, and to other mobile devices. Potential and current applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, 3D television, and cloud computing.The speed and standards of this technology of wireless needs to be at least 100 Megabits per second and up to 1 Gigabit per second to pass as 4G. It also needs to share the network resources to support more simultaneous connections on the cell. As it develops, 4G could surpass the speed of the average wireless broadband home Internet connection. Few devices were capable of the full throttle when the technology was first released. Coverage of true 4G was limited to large metropolitan areas. Outside of the covered areas, 4G phones regressed to the 3G standards. When 4G first became available, it was simply a little faster than 3G. 4G is not the same as 4G LTE which is very close to meeting the criteria of the standards.The major wireless networks were not actually lying to anyone when 4G first rolled out, they simply stretched the truth a bit. A 4G phone had to comply with the standards but finding the network resources to fulfill the true standard was difficult. You were buying 4G capable devices before the networks were capable of delivering true 4G to the device. Your brain knows that 4G is faster than 3G so you pay the price for the extra speed. Marketing 101. The same will probably be true when 5G hits the markets.


4G LTE – Long Term Evolution – LTE sounds better. This buzzword is a version of 4G that is the latest advertised technology and is getting very close to the speeds needed as the standards are set. When you start hearing about LTE Advanced, then we will be talking about true fourth generation wireless technologies because they are the only two formats realized by the International Telecommunications Union as True 4G at this time. But forget about that because 5G is coming soon to a phone near you. Then there is XLTE which is a bandwidth charger with a minimum of double the bandwidth of 4G LTE and is available anywhere the AWS spectrum is initiated.
Verizon, T-Mobile and Sprint have all advanced to the LTE technology with each carrier adding their own combination of wireless technologies, including XLTE, to enhance the spectrum
 4.5G provides better performance than 4G systems, as an interim step towards deployment of full 5G capability The technology includes:

LTE Advanced

 5G – There are rumors of 5G being tested although the specifications of 5G have not been formally clarified. We can expect that new technology to be rolled out around 2020 but in this fast-paced world it will probably be much sooner than that. Seems like a long ways away but time flies and so will 5G at speeds of 1-10Gbps


5G is a generation currently under development. It denotes the next major phase of mobile telecommunications standards beyond the current 4G/IMT-Advanced standards.
NGMN Alliance or Next Generation Mobile Networks Alliance define 5G network requirements as:

• Data rates of several tens of Mb/s should be supported for tens of thousands of users.
• 1 Gbit/s to be offered, simultaneously to tens of workers on the same office floor.
• Several hundreds of thousands of simultaneous connections to be supported for massive sensor deployments.
• Spectral efficiency should be significantly enhanced compared to 4G.
• Coverage should be improved.
• Signalling efficiency enhanced.
• Latency should be significantly reduced compared to LTE.

Next Generation Mobile Networks Alliance feel that 5G should be rolled out by 2020 to meet business and consumer demands.In addition to simply providing faster speeds, they predict that 5G networks will also need to meet the needs of new use-cases such as the Internet of Things as well as broadcast-like services and lifeline communications in times of disaster.

what is smartphone

 Smartphone

A smartphone is a handheld personal computer with a mobile operating system and an integrated mobile broadband cellular network connection for voice, SMS, and Internet data communication; most, if not all, smartphones also support Wi-Fi. Smartphones are typically pocket-sized, as opposed to tablet computers, which are much larger.

 

The first smartphone was IBM's Simon, which was presented as a concept device -- rather than a consumer device -- at the 1992 COMDEX computer trade show. It was capable of sending emails and faxes, as well as keeping a calendar of events for the user, as opposed to simply making calls and sending messages.
Consumer smartphones evolved away from personal digital assistants (PDAs) around the turn of the 21^st century when devices such as the PalmPilot began to include wireless connectivity. Several manufacturers, including Nokia and Hewlett Packard, released devices in 1996 that were combinations of PDAs and typical cellphones that included early operating systems (OSes) and web browsing capabilities. BlackBerry released its first smartphones in the mid-2000s, and they became very popular with consumers and in the enterprise.
Many of these early smartphones featured physical keyboards.

Get to know the features that make up a smartphone.

In 2007, LG released the Prada and Apple released the iPhone, the first smartphones to feature a touchscreen. HTC released its Dream smartphone a year later, which was the first to include Google's Android OS.
Smartphones are able to run a variety of software components, known as “apps”. Most basic apps (e.g. event calendar, camera, web browser) come pre-installed with the system, while others are available for download from official sources like the Google Play Store or Apple App Store. Apps can receive bug fixes and gain additional functionality through software updates; similarly, operating systems are able to update. Mobile payment is now a feature of most smartphones.
Modern smartphones have a touchscreen color display with a graphical user interface that covers the front surface and enables the user to use a virtual keyboard to type and press onscreen icons to activate apps.
Today, smartphones largely fulfill their users' needs for a telephone, digital camera and video camera, GPS navigation, a media player, clock, news, calculator, web browser, handheld video game player, flashlight, compass, an address book, note-taking, digital messaging, an event calendar, etc. Typical smartphones will include one or more of the following sensors: magnetometer, proximity sensor, barometer, gyroscope, or accelerometer. Since 2010, smartphones have adopted integrated virtual assistants, such as Apple Siri, Amazon Alexa, Google Assistant, Microsoft Cortana, BlackBerry Assistant and Samsung Bixby. Most smartphones produced from 2012 onward have high-speed mobile broadband 4G LTE.
In 1999, the Japanese firm NTT DoCoMo released the first smartphones to achieve mass adoption within a country.Smartphones sales started to grow rapidly by the late 2000s. In the third quarter of 2012, one billion smartphones were in use worldwide.Global smartphone sales surpassed the sales figures for feature phones in early 2013.

History

Forerunner

IBM Simon and charging base (1994).

The first commercially available device that could be properly referred to as a "smartphone" began as a prototype called "Angler" developed by Frank Canova in 1992 while at IBM and demonstrated in November of that year at the COMDEX computer industry trade show.A refined version was marketed to consumers in 1994 by BellSouth under the name Simon Personal Communicator. In addition to placing and receiving cellular calls, the touchscreen-equipped Simon could send and receive faxes and emails. It included an address book, calendar, appointment scheduler, calculator, world time clock, and notepad, as well as other visionary mobile applications such as maps, stock reports and news.The term "smart phone" or "smartphone" was not coined until a year after the introduction of the Simon, appearing in print as early as 1995, describing AT&T's PhoneWriter Communicator.

Early integration of data signals with telephony

The first caller identification receiver (1971).

The first integration of data signals with telephony was conceptualized by Nikola Tesla in 1909 and pioneered by Theodore Paraskevakos beginning in 1968 with his work on transmission of electronic data through telephone lines. In 1971, while he was working with Boeing in Huntsville, Alabama, Paraskevakos demonstrated a transmitter and receiver that provided additional ways to communicate with remote equipment. This formed the original basis for what is now known as caller ID. The first caller ID equipment was installed at Peoples' Telephone Company in Leesburg, Alabama and was demonstrated to several telephone companies. The original and historic working models are still in the possession of Paraskevakos.

PDA/phone hybrids

Main article: Personal digital assistant

In the mid-late 1990s, many people who had mobile phones carried a separate dedicated PDA device, running early versions of operating systems such as Palm OS, Newton OS, Symbian or Windows CE/Pocket PC. These operating systems would later evolve into early mobile operating systems. Most of the "smartphones" in this era were hybrid devices that combined these existing familiar PDA OSes with basic phone hardware. The results were devices that were bulkier than either dedicated mobile phones or PDAs, but allowed a limited amount of cellular Internet access. The trend at the time, however, that manufacturers competed on in both mobile phones and PDAs was to make devices smaller and slimmer. The bulk of these smartphones combined with their high cost and expensive data plans, plus other drawbacks such as expansion limitations and decreased battery life compared to separate standalone devices, generally limited their popularity to "early adopters" and business users who needed portable connectivity.
In March 1996, Hewlett-Packard released the OmniGo 700LX, a modified HP 200LX palmtop PC with a Nokia 2110 mobile phone piggybacked onto it and ROM-based software to support it. It had a 640×200 resolution CGA compatible four-shade gray-scale LCD screen and could be used to place and receive calls, and to create and receive text messages, emails and faxes. It was also 100% DOS 5.0 compatible, allowing it to run thousands of existing software titles, including early versions of Windows.

The Nokia 9000 Communicator (right) and the updated 9110 model (left)

In August 1996, Nokia released the Nokia 9000 Communicator, a digital cellular PDA based on the Nokia 2110 with an integrated system based on the PEN/GEOS 3.0 operating system from Geoworks. The two components were attached by a hinge in what became known as a clamshell design, with the display above and a physical QWERTY keyboard below. The PDA provided e-mail; calendar, address book, calculator and notebook applications; text-based Web browsing; and could send and receive faxes. When closed, the device could be used as a digital cellular telephone.
In June 1999 Qualcomm released the "pdQ Smartphone", a CDMA digital PCS smartphone with an integrated Palm PDA and Internet connectivity.
Subsequent landmark devices included:

• The Ericsson R380 (2000) by Ericsson Mobile Communications. The first device marketed as a "smartphone", it was the first Symbian-based phone, with PDA functionality and limited Web browsing on a resistive touchscreen utilizing a stylus. Users could not install their own software on the device, however.
• The Kyocera 6035 (early 2001), a dual-nature device with a separate Palm OS PDA operating system and CDMA mobile phone firmware. It supported limited Web browsing with the PDA software treating the phone hardware as an attached modem.
• Handspring's Treo 180 (2002), the first smartphone that fully integrated the Palm OS on a GSM mobile phone having telephony, SMS messaging and Internet access built in to the OS. The 180 model had a thumb-type keyboard and the 180g version had a Graffiti handwriting recognition area, instead.

Mass adoption in Japan

In 1999, the Japanese firm NTT DoCoMo released the first smartphones to achieve mass adoption within a country. These phones ran on i-mode, which provided data transmission speeds up to 9.6 kbit/s. Unlike future generations of wireless services, NTT DoCoMo's i-mode used cHTML, a language which restricted some aspects of traditional HTML in favor of increasing data speed for the devices. Limited functionality, small screens and limited bandwidth allowed for phones to use the slower data speeds available.The rise of i-mode helped NTT DoCoMo accumulate an estimated 40 million subscribers by the end of 2001. It was also ranked first in market capitalization in Japan and second globally. This power would later wane in the face of the rise of 3G and new phones with advanced wireless network capabilities.

Early smartphones outside Japan

Several BlackBerry smartphones, which were highly popular in the mid-late 2000s.

Smartphones were still rare outside Japan until the introduction of the Danger Hiptop in 2002, which saw moderate success among U.S. consumers as the T-Mobile Sidekick. Later, in the mid-2000s, business users in the U.S. started to adopt devices based on Microsoft's Windows Mobile, and then BlackBerry smartphones from Research In Motion. American users popularized the term "CrackBerry" in 2006 due to the BlackBerry's addictive nature.
Outside the U.S. and Japan, Nokia was seeing success with its smartphones based on Symbian, originally developed by Psion for their personal organisers, and it was the most popular smartphone OS in Europe during the middle to late 2000s. Initially, Nokia's Symbian smartphones were focused on business with the Eseries, similar to Windows Mobile and BlackBerry devices at the time. From 2006 onwards, Nokia started producing consumer-focused smartphones, popularized by the entertainment-focused Nseries. In Asia, with the exception of Japan, the trend was similar to that of Europe. Until 2010, Symbian was the world's most widely used smartphone operating system.

Form factor shift

The original Apple iPhone. Its introduction contributed to the steady rise of smartphones that feature large touchscreen interfaces without physical keypads.

In the early to mid-2000s, it was common for smartphones to have a physical T9 numeric keypad or QWERTY keyboard in either a candybar or sliding form factor. At that time, many smartphones had resistive touchscreens, which allowed for input with a stylus in addition to fingers, thus allowing the entry of Asian characters.Keyboards were also common for smartphones in the late-2000s.
In 2007, the LG Prada was the first mobile phone released with a large capacitive touchscreen.Later that year, Apple Inc. introduced the iPhone, which used a multi-touch capacitive touch screen.Such phones were notable for abandoning the use of a stylus, keyboard, or keypad typical for smartphones at the time up till the early 2010s, in favor of a capacitive touchscreen for direct finger input as its only input type. The iPhone was "not a smartphone by conventional terms, being that a smartphone is a platform device that allows software to be installed",until the opening of Apple's App Store a year later, which became a common means for smartphone software distribution and installation.
In October 2008, the first phone to use Google's Android operating system, called the HTC Dream (also known as the T-Mobile G1), was released. It was also a smartphone with a large multi-touch touchscreen, but still retained a slide-out physical keyboard. Later versions of Android added and then improved on-screen keyboard support, and physical keyboards on Android devices quickly became rare. Although Android's adoption was relatively slow at first, it started to gain widespread popularity in 2012, and in early 2012 dominated the smartphone market share worldwide, which continues to this day.
The iPhone and Android phones with their capacitive touchscreens popularized the smartphone form factor based on a large capacitive touchscreen and led to the decline of earlier, keyboard- and keypad-focused platforms. Microsoft, for instance, discontinued Windows Mobile and started a new touchscreen-oriented OS from scratch, called Windows Phone. Nokia abandoned Symbian and partnered with Microsoft to use Windows Phone on its smartphones. Windows Phone became the third-most-popular smartphone OS, before being replaced by Windows 10 Mobile, which declined in share to become "largely irrelevant" at less than 0.5% of the smartphone market. Palm replaced their Palm OS with webOS, which was bought by Hewlett-Packard and later sold to LG Electronics for use on LG smart TVs. BlackBerry Limited, formerly known as Research In Motion, made a new platform based on QNX, BlackBerry 10, with which it was possible to control a device without having to press any physical buttons; this platform was later discontinued.
By the mid-2010s, almost all smartphones were touchscreen-only, and Android and iPhone smartphones dominated the market since smartphones started to grow in use by 2012 and 2013.

Technological developments in the 2010s

Wikipedia homepages are shown on smartphones

In 2013, Fairphone launched its first "socially ethical" smartphone at the London Design Festival to address concerns regarding the sourcing of materials in the manufacturing.In late 2013, QSAlpha commenced production of a smartphone designed entirely around security, encryption and identity protection. Some companies began to release smartphones incorporating flexible displays to create curved form factors, such as the Samsung Galaxy Round and LG G Flex.
In October 2013, Motorola Mobility announced Project Ara, a concept for a modular smartphone platform that would allow users to customize and upgrade their phones with add-on modules that attached magnetically to a frame.Ara was retained by Google following its sale of Motorola Mobility to Lenovo, but was shelved in 2016.That year, LG and Motorola both unveiled smartphones featuring a limited form of modularity for accessories; the LG G5 allowed accessories to be installed via the removal of its battery compartment,while the Moto Z utilizes accessories attached magnetically to the rear of the device.
By 2014, 1440p displays began to appear on high-end smartphones. In 2015, Sony released the Xperia Z5 Premium, featuring a 4K resolution display, although only images and videos could actually be rendered at that resolution (all other software is upscaled from 1080p). Microsoft, expanding upon the concept of Motorola's short-lived "Webtop", unveiled functionality for its Windows 10 operating system for phones that allows supported devices to be docked for use with a PC-styled desktop environment.Other major technologies began to trend in 2016, including a focus on virtual reality and augmented reality experiences catered towards smartphones, the newly introduced USB-C connector, and improving LTE technologies.As of 2015, the global median for smartphone ownership was 43%.Statista has forecast that 2.87 billion people will own smartphones in 2020.
The first mobile phone with a fingerprint scanner was the Toshiba G500 in 2007 and the first smartphone with a fingerprint scanner was the Motorola Atrix 4G in 2011.In September 2013, the iPhone 5S was unveiled as the first smartphone on a major U.S. carrier since the Atrix to feature the technology, which was called Touch ID.This feature proved popular with users and by 2017 all of Apple's major competitor's included a fingerprint scanner.

Mobile phone

A mobile phone, known as a cell phone in North America, 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, 2000s-era mobile phones support a variety of other services, such as text messaging, MMS, email, Internet access, short-range wireless communications (infrared, Bluetooth), 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.
The first handheld mobile phone was demonstrated by John F. Mitchell and Martin Cooper of Motorola in 1973, using a handset weighing c. 2 kilograms (4.4 lbs). In 1979, Nippon Telegraph and Telephone (NTT) launched the world's first cellular network in Japan. In 1983, the Dynastic 8000x was the first commercially available handheld mobile phone. From 1983 to 2014, worldwide mobile phone subscriptions grew to over seven billion, penetrating virtually 100% of the global population and reaching even the bottom of the economic pyramid.In first quarter of 2016, the top smartphone developers worldwide were Samsung, Apple, and Huawei (and "[s]martphone sales represented 78 percent of total mobile phone sales").For feature phones (or "dumbphones") as of 2016, the largest were Samsung, Nokia, and Alcatel

 History
 A handheld mobile radio telephone service was envisioned in the early stages of radio engineering. In 1917, Finnish inventor Eric Tigerstedt filed a patent for a "pocket-size folding telephone with a very thin carbon microphone". Early predecessors of cellular phones included analog radio communications from ships and trains. The race to create truly portable telephone devices began after World War II, with developments taking place in many countries. The advances in mobile telephony have been traced in successive "generations", starting with the early zeroth-generation (0G) services, such as Bell System's Mobile Telephone Service and its successor, the Improved Mobile Telephone Service. These 0G systems were not cellular, supported few simultaneous calls, and were very expensive.

The first handheld cellular mobile phone was demonstrated by John F. Mitchell and Martin Cooper of Motorola in 1973, using a handset weighing 2 kilograms (4.4 lb).The first commercial automated cellular network was launched in Japan by Nippon Telegraph and Telephone in 1979. This was followed in 1981 by the simultaneous launch of the Nordic Mobile Telephone (NMT) system in Denmark, Finland, Norway, and Sweden.Several other countries then followed in the early to mid-1980s. These first-generation (1G) systems could support far more simultaneous calls but still used analog cellular technology. In 1983, the DynaTAC 8000x was the first commercially available handheld mobile phone.
In 1991, the second-generation (2G) digital cellular technology was launched in Finland by Radiolinja on the GSM standard. This sparked competition in the sector as the new operators challenged the incumbent 1G network operators.
Ten years later, in 2001, the third generation (3G) was launched in Japan by NTT DoCoMo on the WCDMA standard.This was followed by 3.5G, 3G+ or turbo 3G enhancements based on the high-speed packet access (HSPA) family, allowing UMTS networks to have higher data transfer speeds and capacity.
By 2009, it had become clear that, at some point, 3G networks would be overwhelmed by the growth of bandwidth-intensive applications, such as streaming media.Consequently, the industry began looking to data-optimized fourth-generation technologies, with the promise of speed improvements up to ten-fold over existing 3G technologies. The first two commercially available technologies billed as 4G were the WiMAX standard, offered in North America by Sprint, and the LTE standard, first offered in Scandinavia by TeliaSonera.

 Types of phone
 *Smartphone
* Feature phone
* Kosher phone

 *Smartphones have a number of distinguishing features. The International Telecommunication Union measures those with Internet connection, which it calls Active Mobile-Broadband subscriptions (which includes tablets, etc.). In the developed world, smartphones have now overtaken the usage of earlier mobile systems. However, in the developing world, they account for around 50% of mobile telephony

* Feature phone is a term typically used as a retronym to describe mobile phones which are limited in capabilities in contrast to a modern smartphone. Feature phones typically provide voice calling and text messaging functionality, in addition to basic multimedia and Internet capabilities, and other services offered by the user's wireless service provider. A feature phone has additional functions over and above a basic mobile phone which is only capable of voice calling and text messaging. Feature phones and basic mobile phones tend to use a proprietary, custom-designed software and user interface. By contrast, smartphones generally use a mobile operating system that often shares common traits across devices.

* There are Orthodox Jewish religious restrictions which, by some interpretations, standard mobile telephones overstep. To deal with this problem, some rabbinical organizations have recommended that phones with text-messaging capability not be used by children.Phones with restricted features are known as kosher phones and have rabbinical approval for use in Israel and elsewhere by observant Orthodox Jews. Although these phones are intended to prevent immodesty, some vendors report good sales to adults who prefer the simplicity of the devices. Some phones are approved for use by essential workers (such as health, security, and public service workers) on the sabbath, even though the use of any electrical device is generally prohibited during this time.
.
Phone Hardware

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. These are a keypad for feature phones and touch screens for most smartphones.
• A screen which echoes the user's typing, and displays text messages, contacts, and more.
• 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 an R-UIM.
• Individual GSM, WCDMA, iDEN and some satellite phone devices are uniquely identified by an International Mobile Equipment Identity (IMEI) number.

Low-end mobile phones are often referred to as feature phones and offer basic telephony. Handsets with more advanced computing ability through the use of native software applications are known as smartphones

.

Sound

In sound, smartphones and feature phones vary little. Some audio-quality enhancing features, such as Voice over LTE and HD Voice, have appeared and are often available on newer smartphones. Sound quality can remain a problem due to the design of the phone, the quality of the cellular network and compression algorithms used in long distance calls.Audio quality can be improved using a VoIP application over WiFi. Cellphones have small speakers so that the user can use a speakerphone feature and talk to a person on the phone without holding it to their ear. The small speakers can also be used to listen to digital audio files of music or speech or watch videos with an audio component, without holding the phone close to the ear.

Battery and battery life

The average phone battery lasts 2-3 years at best. Many of the wireless devices use a Lithium-Ion (Li-Ion) battery, which charges 500-2500 times, depending on how users take care of the battery and the charging techniques used. It is only natural for these rechargeable batteries to chemically age, which is why the performance of the battery when used for a year or two will begin to deteriorate. Battery life can be extended by draining it regularly, not overcharging it, and keeping it away from heat.

SIM card

Main articles: Subscriber Identity Module and Removable User Identity Module

Typical mobile phone mini-SIM card.

GSM feature phones require a small microchip called a Subscriber Identity Module or SIM card, in order 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) and the K_i used to identify and authenticate the user of the mobile phone. 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, provided that this is not prevented by a SIM lock. The first SIM card was made in 1991 by Munich smart card maker Giesecke & Devrient for the Finnish wireless network operator Radiolinja
A hybrid mobile phone can hold up to four SIM cards, with a phone having an IMEI per SIM Card. SIM and R-UIM cards may be mixed together to allow both GSM and CDMA networks to be accessed. From 2010 onwards, such phones became popular in emerging markets, and this was attributed to the desire to obtain the lowest on-net calling rate.

Infrastructure

Main articles: Cellular network and WiFi

Mobile phones communicate with cell towers that are placed to give coverage across a telephone service area which is divided up into 'cells'. Each cell uses a different set of frequencies from neighbouring cells, and will typically be covered by 3 towers placed at different locations. The cell towers are usually interconnected to each other and the phone network and the internet by wired connections. Due to bandwidth limitations each cell will have a maximum number of cell phones it can handle at once. The cells are therefore sized depending on the expected usage density, and may be much smaller in cities. In that case much lower transmitter powers are used to avoid broadcasting beyond the cell.
As a phone moves around, a phone will "hand off"- automatically disconnect and reconnect to the tower that gives the best reception.
Additionally, short-range Wi-Fi infrastructure is often used by smartphones as much as possible as it offloads traffic from cell networks on to local area networks.

Software

Text messaging

Main article: SMS

A text message (SMS).

A common data application on mobile phones is Short Message Service (SMS) text messaging. The first SMS 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 and subsequently many organizations provided "on-demand" and "instant" news services by SMS. Multimedia Messaging Service (MMS) was introduced in 2001

Batata Vada Recipe

It’s a monsoon time and what could be the better way to enjoy the cool breeze of air with warm Batata vada with spicy coriander chutney? This street food of Mumbai is almost guaranteed to be found at every chat vendor’s stall in entire Maharashtra and key ingredient in Pav-Vada – a

staple food for hard working Maharashtrians. Follow this step by step photo recipe to learn how you can make this yummy snack at home in just 20 minutes and enjoy the monsoon to the fullest without worrying about the health risks of eating street food.


Ingredients 
3 medium Potatoes, boiled
1/4 teaspoon Mustard Seeds
A pinch of Asafoetida
2 Green Chillies, chopped (or more to taste)
1/2 inch piece of Ginger, chopped
2 cloves of Garlic, chopped, optional
3-4 Curry Leaves, finely chopped
1/3 cup finely chopped Coriander Leaves
1/4 teaspoon Turmeric Powder
1 teaspoon Lemon Juice or 1/2 teaspoon Dry Mango Powder, optional
1/2 cup Gram Flour (besan/ chickpea flour/ chana flour)
1/3 cup Water (or more)
A pinch of Baking Soda (soda bi carbonate)
2 teaspoons Oil + for deep frying
Salt to taste

Have all the ingredients ready before starting to make vada. Make a paste of green chilli, ginger and garlic using mortar and pestle or in the small chutney jar of a mixer grinder.

Directions:
Have all the ingredients ready before starting to make vada. Make a paste of green chilli, ginger and garlic using mortar and pestle or in the small chutney jar of a mixer grinder.
Peel boiled potatoes and mash them with backside of a large spoon.
Heat 2-teaspoons oil in a small pan over medium flame. Add mustard seeds. When they start to crackle, add asafoetida, curry leaves and a paste of green chilli-ginger-garlic.
Stir and cook for a minute. Add turmeric powder and mix well.

Turn off the flame and transfer the prepared tempering over mashed potatoes. Add chopped coriander leaves, lemon juice and salt.
Mix well and taste for the lemon juice and salt. If required, add more lemon juice or salt.
Divide it into 9-10 equal portions. If mixture turns sticky, grease your hands with oil and make round shaped balls from it.
Prepare batter for vada – take gram flour, baking soda and salt in a wide mouthed bowl.
Add water (approx. 1/3 cup) little by little and stir continuously and make a lump free smooth batter. Consistency of the batter should be slightly thinner than dosa batter. If batter is too watery then add 1-2 teaspoons gram flour and if it is too thick then add little water and mix well.
Heat oil in a pan over medium flame for deep-frying. When oil is medium hot, dip each potato ball into batter and coat it evenly with hand or spoon and gently drop it into the hot oil. Drop 3-4 balls in a single batch and deep-fry them until light golden brown.
Drain excess oil using perforated spoon and transfer them over paper napkin on a plate. Deep-fry remaining balls. Batata Vada is now ready for serving. Serve hot with tea and green chutney / tomato ketch up.


Tips and Variations:

Mashed potato mixture will turn sticky if boiled potato has excessive moisture. If mashed potato has excess moisture, cook it in a non-stick pan until excess moisture evaporates. Transfer it to a bowl, let it cool for few minutes and then add tempering and mix properly.
Add 1/2-teaspoon cumin seeds and 1/4-teaspoon urad dal with mustard seeds for variation.
If you want to make them in large quantity, prepare the vadas in advance and deep fry them again at the time of serving for crispy outer layer.
Taste:  Crispy from outside and soft and spicy from inside

पालक की सूखी सब्जी

परिचय
पालक आलू की सूखी सब्जी बहुत ही स्वादिष्ट बनती हैं. पालक में मिनरल्स, आइरन भरपूर मात्रा में पाये जाते हैं, ये सब्जी सप्ताह में एक बार बनाते रहें, अच्छी सब्जी है

आवश्यक सामग्री

पालक - 750ग्राम
आलू - 5(250 ग्राम)
सरसों का तेल - 2 टेबल स्पून
हींग - 1 पिंच
जीरा - 1/2 छोटी चम्मच
हल्दी पाउडर - 1/4 छोटी चम्मच
धनिया पाउडर - 1 छोटी चम्मच
लाल मिर्च - 1/4 छोटी चम्मच से कम या स्वादानुसार
हरी मिर्च - 2 ( बारीक कटी हुई)

नमक - 1 छोटी चम्मच से कम 

विधि

पालक को साफ करें, और डंडियां तोड़कर हटा कर, 2 बार साफ पानी से धो लें, छलनी में रखकर पानी निकाल दीजिए, पानी सूख जाने पर पालक को बारीक काट लीजिए.

आलू को छील कर धो लीजिए और 1-1 इंच के टुकड़ों में काट लीजिए.


पैन में तेल डालकर गरम करें. तेल के गरम होने पर हींग और जीरा डाल दें. जीरा भूनने पर हरी मिर्च, हल्दी पाउडर और धनिया पाउडर डाल कर मसालों को थोडा़ सा भून लीजिए. अब आलू डालकर मिला दीजिए और 1/4 कप पानी डालकर आलू को ढककर धीमी आंच पर 5 मिनिट पकने दीजिए.

आलू को अच्छे से चला दीजिए अब पालक डालकर, ढककर फिर से 5 मिनिट के लिए पकने दीजिए. सब्जी को चैक कीजिए, अच्छे से चला दीजिये. नमक, लाल मिर्च पाउडर डालकर मिला दीजिए.

चैक कीजिये आलू अगर नरम हो गये है, और सब्जी में थोड़ा पानी दिख रहा है, तब सब्जी को बिना ढके पकायें ताकि सब्जी में अगर पानी है तो वह सूख जाए. आपकी पालक आलू की सब्जी तैयार है.


सब्जी को प्याले में निकाल लीजिए. और गरमा गरम पालक आलू की सूखी सब्जी, परांठे, नॉन, चपाती या चावल किसी के भी साथ परोसें और खायें.

ग्वार फली की सब्जी

परिचय
ग्वार की फली (Cluster Beans Fry) की सब्जी उत्तर भारत में बनाई जाती है, यह बहुत ही स्वादिष्ट सब्जी होती है. आज हम ग्वार की फली की सब्जी ही बनायेगें

आवश्यक सामग्री
ग्वार की फली - 500ग्राम 
तेल-1 1/2टेबल स्पून
हींग -1 पिंच
जीरा- 1/2 छोटी चम्मच
हल्दी पाउडर- 1/2 छोटी चम्मच
धनिया पाउडर- 1 छोटी चम्मच
लाल मिर्च पाउडर-- 2 पिंच
हरी मिर्च -2 ( बारीक कटी हुई)
नमक - 3/4 छोटी चम्मच या स्वादानुसार
हरा धनिया - 1 टेबल स्पून (बारीक कटा हुआ)
गरम मसाला- 1/4 छोटी चम्मच से थोड़ा कम

अमचूर पाउडर - 1/4 छोटी चम्मच

ग्वार की फलियों को अच्छी तरह धो लीजिए. इन फलियों के दोनों तरफ से डंठल तोड़िए और फली को तोड़ते हुए किनारों पर से धागे निकाल दीजिए. सारी फली के इसी प्रकार टुकड़े कर लीजिए.
कढ़ाही में तेल डाल कर गरम कीजिए. गरम तेल में हींग और जीरा डाल दीजिए. जीरा हल्का ब्राउन होने के बाद, इसमें हल्दी पाउडर, धनिया पाउडर और हरी मिर्च डालिए, मसाले को चमचे से मिलायें. इसके बाद कटी हुई ग्वार की फली, नमक और लाल मिर्च पाउडर डालकर फलियों को चमचे से लगातर चलाते हुए 2-3 मिनिट तक भून लीजिए.  सब्जी में एक टेबल स्पून पानी डालकर मिला दीजिए. सब्जी को ढककर 5 से 6 मिनिट के लिये धीमी गैस पर पकने दीजिए.

सब्जी का ढक्कन खोलिए. सब्जी चमचे से चलाइए, फलियां अभी नरम नही हुई है, सब्जी को फिर से ढककर 3 से 4 मिनिट धीमी आंच पर पकने दीजिए. 4 मिनिट बाद, सब्जी चैक कीजिए. फलियां नरम हैं.  सब्जी में गरम मसाला और अमचूर पाउडर डालकर चमचे से मिला दीजिए. गैस बंद कर दीजिए.


सब्जी तैयार है, इसमें हरा धनिया डालकर मिक्स कर दीजिए.

सहजन की सब्जी

जितनी खाने में स्वादिस्ट लगति है, उतनी ही सहजन के फायदे भी है। सहजन की nutritional value बहुत अधिक है। सहजन में विटामिन,मिनरल,पोटेशियम, कैल्शियम प्रचुर मात्रा में पाई जाती है। सहजन लिवर को भी प्रोटेक्ट करता है।इसमे पाये जाने वाली मिनरल और, कैलसियम के कारण हड्डियों को मजबूती मिलती है।सहजन के खाने से बहुत सारे बीमारियो से हम दुर रहते है। आइये सहजन की सब्जी बनाना सीखते है।

सामग्री
8-10 सहजन (1 इंच के टुकडो में कटा हुआ) (अगर पतला वाला सहजन है तो एक गड्डी)

1 कप कटे हुए आलू

2-3 टमाटर (बारीक कटे हुए)

½ चम्मच जीरा पाउडर

1 चम्मच धनिया पाउडर

2 चम्मच तेल

½ चम्मच जीरा

स्वादानुसार नमक

½ छोटा चम्मच काली मिर्च का पाउडर

1 छोटा चम्मच हल्दी

2 बड़े चम्मच बारीक काट हरी धनिया

पेस्ट बनाने के लिए

2 बड़े चम्मच पीली सरसों

8 -10 लहसुन की कलियाँ

4-5 हरी मिर्च
विधि
एक कढाई में तेल डाल के गर्म करे, जीरा डाल के तड़कने दे. कटा हुआ आलू डाल  के कुछ देर भूने,

फिर सहजन भी डाल दे आलू के सुनहरा होने तक भूने. सारे सूखे मसाले, नमक, और कटे हुए टमाटर डाल के कुछ देर पकाए.

पिसी हुई सरसो का पेस्ट डाल के मिला दे. एक कप पानी डाल के धीमी आंच पर आलू के पकने तक पकाए.


गैस बंद करके हरी धनिया डाल के गरम गरम सब्जी चावल या रोटी के साथ परोसे.