Technology Overview

Smartphone technology is evolving at a very rapid pace. To help you keep track of developments, we’ve created this technical overview. It explains, in a clear and concise way, how each of the major components in a Smartphone works. For additional detail, we’ve also created a set of technical specifications that should help you find the exact components you’ll want in your Smartphone. You can learn more by following the links at the end of each overview section.

Smartphone Displays

No matter how you plan to use your Smartphone, selecting one with a screen that fits your needs will be key to your long term satisfaction. Many different factors help to determine which display best suits your needs. Chief among them are:

  • Luminance (the ability of screens to be seen outdoors or in bright light);
  • Contrast Ratio (the ability of screens to be seen indoors or in low light)
  • Color Depth (the total number of colors a screen can display)
  • Screen Size (measured diagonally)
  • Resolution (the total number of pixels on the screen)
  • Pixel Density (the key number that determines the screen’s crispness and clarity)
  • Glare Resistance (determines how susceptible is a screen to washout)
  • Display Technology (how the screen actually works)

All these factors combine to determine the overall quality of a screen.

A display’s brightness (or luminance) is determined by the amount of light emitted, measured in candelas per square meter (cd/m²). The brighter the display the better.
Bright displays are needed in sunlit environments (outdoors or well lit interiors) to create sufficient contrast for screen images to be seen clearly. Most Smartphone displays have a luminance that ranges from 200 to 550 cd/m2. By comparison, HDTVs range from 450 to about 1000 cd/m2. A luminance of at least 800 cd/m2 is required for a screen to be easily viewable in direct sunlight.
Contrast Ratio
Contrast Ratio measures the difference between the brightest white and the darkest black that a screen can display. Screens with high contrast ratios produce crisp images with subtle color variations and easy to read text. It is an excellent measure of a Smartphone screen’s readability.
Based on the screen technology employed, contrast ratios on Smartphones range from several hundred to one to tens of thousands to one.
Basic Display: below 1000:1
Standard Display: above 1,000:1
Performance Display: above 10,000:1
Color Depth
Color depth indicates the number of colors a device is capable of displaying on the screen (aka its Color Gamut). The higher the number, the better.
For Smartphones, a “standard” device can be expected to display 65,536 colors (16 bit color). A “performance” device can be expected to display 16.7 million colors (24-bit color).
Screen Size
Determining which screen size works best for you requires that you find a balance between readability and portability. If you pick a phone that’s too small, it’s screen is unreadable. If you pick a screen that’s too big, the phone won’t fit comfortably in your hand, your pocket or your purse.
Smartphone screens are measured diagonally.(i.e. the distance between two diagonally opposing corners of the screen). The current crop of Smartphones have screens that measure between 2.2” (56mm) and 5” (127mm). The most popular Smartphones have screens that measure at least 3.5” (89mm). Screens below 2.5” (64mm) are hard to see and difficult to navigate. Too much panning and zooming is required. Most users find the experience unpleasant and fatiguing. This is especially true for older users and the visually impaired.
Smartphone manufacturers group their screens into the following categories:
Small size screens: below 3”.
Medium sized screens: between 3” to 4”
Large size screens: more than 4”.
Screen Size is combined with Pixel Count to determine a screen’s Pixel Density.
Resolution (aka Pixel Count) is one of the ways that manufacturers have of describing screen quality. It’s simply a tally of the total number of pixels on a screen. In theory, the higher the number, the better the screen.
Resolution can be combined with Screen Size to determine a screen’s Pixel Density..
Pixel Density
Pixel Density is the single most important indicator of screen quality. It is measured in pixels per inch (ppi). The higher the number, the better the screen and the crisper the image.
Screens with a pixel density below 200 ppi are considered low resolution. Screens with pixel densities between 200 and 300 ppi are considered to be average quality. Screens with a pixel density above 300 ppi are considered high resolution.
Selection tip: if you compare two different Smartphones with the same size screen, and all other considerations are equal, pick the one that has the higher pixel density.
Glare Resistance
Display Technology
The Smartphone market is dominated by 3 different display technologies. The most popular is called Thin Film Transistor Liquid Crystal Displays (TFT-LCD). TFT-LCD screens are relatively low cost and easy to produce. They work well in indoor light. Despite their popularity, they have some significant drawbacks. Most importantly, TFT-LCD screens can only be viewed from a narrow angle (typically about 35 °). In addition, TFT-LCD screens can only display a limited range of colors, and colors tend to shift as viewing angles change. TFT-LCD’s have a relatively slow screen refresh rate (aka image switching) which makes the technology unsuitable for watching HD videos.
In-Plane Switching Liquid Crystal Display (IPS-LCD) screens are an advanced version of TFT-LCD technology. IPS-LCD screens can be viewed from much wider angles than TFT-LCD screens. The technology renders colors very accurately (i.e. it supports a wide color gamut) and has a high contrast ratio which means it can be viewed in direct sunlight and used very effectively as an eBook reader. All-in-all, IPS-LCD screens have better picture quality than a conventional LCD’s and they consume less power.
Super Active-Matrix Organic Light Emitting Diode (Super AMOLED) display technology is currently considered the best on the market. They are light weight and durable. They can be viewed from a very wide angle with no image distortion of color shift. They have a very high screen refresh rate which makes them ideal for watching HD videos and animation. They are also more energy efficient than older display technologies. In addition, they also have very high contrast ratios so they can be viewed in direct sunlight and used as eBook readers. They render colors very accurately and have the highest pixel density of any Smartphone display technology. The result is superb image quality.


Battery Life
Battery life is an extremely important selection criteria but it’s notoriously difficult to accurately predict. That’s because battery life is highly dependent on the way a phone gets used. But no matter how you use your Smartphone, one thing is for certain: the longer a battery charge lasts, the better.
Even though battery life is hard to predict, cell phone manufacturers usually describe it in terms of “Talk Time” and “Standby Time”. The numbers associated with these terms are useful but should be taken with a grain of salt since manufacturers claims can’t be easily verified and can’t account for the way you’ll use your phone. It’s best to use the advertised times for rough comparisons only. You’ll probably find that web based customer comments are your best source for accurate battery life estimates.
Regardless of how long your battery lasts, it’s always a good idea to have a spare charger and a second fully charged battery on hand in case of emergencies. As an alternative, some folks have found it useful to carry a “Battery Booster” instead of a charger and spare battery. Battery Boosters are clip on devices that provide a rapid recharge or auxiliary power if your battery is fully depleted.
Battery Type
Virtually all Smartphones use Lithium Ion batteries. Recent advances in battery technology (i.e. Lithium-polymer batteries) have not yet found their way into the Smartphone market.
Replaceable Battery
Most Smartphone batteries can be easily replaced by the owner. The iPhone’s battery however is a notable exception


Memory Type & Size
Smartphone memory is best described as either fixed or expandable. Fixed memory (aka internal memory) is primarily used to run the Smartphone. Expandable memory is primarily used to store your programs and data. With rare exceptions, fixed memory cannot be increased or upgraded; whereas expandable memory can always be increased.
The storage capacity of your Smartphone is important because it determines the number of songs, videos, eBooks or photos you can carry around with you. It also determines how many software applications and ring tones you can install on your phone.
Since the capacity of a Smartphone’s internal memory is fixed at the factory, it’s important to find a phone with as much memory as possible. Basic Smartphones usually come with less than 4 GB of internal memory. Standard Smartphones usually come with about 8 GB. Performance Smartphones come with 16 GB or more.
Since expandable memory can always be increased, the amount that’s installed by the factory is immaterial. Higher capacity memory chips can always be substituted as the need arises or additional funds become available. The most popular type of expandable memory card used in Smartphones is a Secure Digital (SD) card. SD cards come in a number of variations so care should be taken to select a phone that’s compatible with the type of flash card you prefer.
Disk Drives
Smartphones don’t contain disk drives (e.g. CD and DVD optical drives or magnetic hard disk drives).

CPU Chips

About 85% of the processors that power Smartphones are based on a design created by a company called ARM Holdings. ARM licenses their chip design to many different manufacturers who in turn produce customized versions of the design to fit their own products.
The current crop of ARM chips contain one or two cores (one or two processors on a single chip) with speeds ranging from 195 MHz to 1 GHz/. Standard devices run above 500 MHz Performance devices run at 720 MHz or more.
The remaining 15% of Smartphone processors are based on a design first introduced by Intel corporation. It’s known as the x86 platform. Chips based on the x86 design are currently manufactured by Intel and AMD.
Both the x86 and ARM platforms are well designed and powerful enough to handle all the tasks a Smartphone is required to perform. The ARM design however seems better able at prolonging battery life. This is an especially useful capability for devices that are expected to maintain continuous wireless connection to the outside world.
Processor Speed
Processor speeds are measured in millions of calculations per second (MHz) or billions of calculations per second (GHz). The higher the speed the better.
Until quite recently, Smartphones were built with only one processor. This made speed comparisons very easy. When chip manufacturers began packaging two or more processors onto a single chip, speed comparisons become a bit more complicated.
Multi-core processors require us to measure speed by determining a chip’s actual throughput not its clock speed. Throughput is determined by adding up all the calculations a chip performs in a second. For example, if we compare a single core processor that has a speed of 1 GHz per second to a dual core processor with the same speed, the dual core processor has twice the throughput.

Connecting to the Outside World

Wireless Communications
Smartphones come with up to 4 different types of built-in radios. Bluetooth allows your Smartphone to communicate with other digital devices in its immediate vicinity. Wi-Fi provides a bigger wireless bubble that allows your Smartphone to connect to a computer network, and through it, the world. Wireless Broadband radio (aka 3G & 4G cell phone networks) connect your Smartphone to the outside world via cell towers. Satellite radio does the same using orbiting satellites. Here’s a closer look at each.
Bluetooth is the name given (by the computer industry) to the low power, short-range radios that are built into virtually all Smartphones. The technology is designed to connect mobile devices like phones to wireless headsets, keyboards or mice..
Wi-Fi is a high speed, medium range, radio technology that’s been built into virtually every Smartphone on the market. It’s primarily used to connect mobile devices like Smartphones to local and wide area networks as well as the Internet. The Wi-Fi standard supports several different transmission speeds. The highest of these speeds supports video streaming.
Wireless broadband is the current state-of-the-art in cell phone technology. It’s a medium power, long range, high speed radio technology that’s built-in to every Smartphone. Within the Wireless Broadband standards, there are several competing technologies and radio formats. Each cell phone service provider chooses the type of radio signal they deploy on their network.
The two key selection criteria related to wireless networks are data transfer speeds and area coverage. The underlying technology that delivers higher and higher data transfer speeds are governed by a set of industry standards that insure the compatibility of handsets and the wireless networks they connect to. They also insure compatibility between wireless networks (i.e. cell phone company to cell phone company).
Wireless phone systems within the same generation have roughly equivalent transmission speeds. Since most cell phone companies in the US are fielding 3G networks, it becomes increasingly important to compare each company’s geographic coverage areas before you select a service provider. Our best advice is to avoid using a company whose service doesn’t extend to areas where you live or frequently travel. Without adequate coverage, even the speediest network is useless. Also remember that torrents of data can easily turn to a trickle if an obstruction gets between you and your cell tower.
A bit of historical background: wireless networks have evolved over time to provide faster and faster voice and data transfer rates. These evolutionary developments can be grouped neatly into generations – each generation being faster than the last.
The first generation of cell phone systems were called 1G networks. These early phone systems used analog radio signals and a technology called “circuit switching” to rout calls around the world. The second generation cell phones systems (aka 2G) began transmitting and receiving digital radio signals and continued to use circuit switching. The third generation cell phone systems (aka 3G) continued to use circuit switching for all voice calls but began using packet switching to transmit data. Forth generation cell phone systems (aka 4G) use packet switching for both voice and data transmissions. Packet switching relies on the IP protocol to rout all its traffic over the internet.
Worldwide Service
The worldwide cell phone market is governed by a set of industry standards that insure that the phones manufacturers produce are compatible with the transmission technology the phone companies are deploying. Adherence to these standards allows phone calls to be seamlessly handed off from one company to another as you travel between coverage areas. If you travel internationally, it’s best to check to see if the countries you will be visiting use the same transmission technology as the Smartphone you are thinking of buying.
Some Smartphones are equipped with special radios that connect to orbiting satellites instead of cell towers. Satellite phones are especially useful If you expect to travel to areas with spotty cell service, Satellite Smartphones are expensive. So are satellite service plans..
Other Specialty Radios:
Some Smartphones come equipped with a built-in Mi-Fi router. These routers use the phone’s connection to its cellular data network to provide a Wi-Fi hot spot for nearby computers.
Although rare, some Smartphones come with a built-in FM receiver.
Text Messaging (aka SMS or Short Message Service) is a standard feature on all Smartphones. The software that enables text messaging comes preinstalled on each handset and is often closely tied to the Smartphone’s operating system. Message length restrictions vary from country to country. In the US, text messages are restricted to 160 characters.
Instant Messaging (IM) is primarily a web based messaging service that provides text, voice and video communication between two or more participants simultaneously (i.e. several simultaneous participants communicating real time over the internet). Instant Messaging also comes as a standard feature on most Smartphones. IM software is usually preinstalled by the manufacturer at the request of the wireless provider. Communications is restricted to others who are part of the same wireless network or those who are using the same software regardless of which network they use. Features vary from software package to software package.
Multimedia Messaging (MMS) is an extension of the SMS text messaging service. MMS is primarily used to send digital photos and videos from camera equipped Smartphones. MMS is also used to deliver news and ring tones. MMS software comes pre-installed on most Smartphones and is closely tied to phone’s operating system.
Email is a standard feature on all Smartphones. Email software (aka clients) are usually preinstalled by the phone manufacturer at the behest of wireless providers. Email clients are often tied to the Smartphone’s OS. Features vary from client to client. Smartphones can be linked to many different email accounts at the same time so users can access their personal and business accounts simultaneously.
If you think you’re going to use any or all of these services, check to see if they are included in your service contract. If not, you may be incurring additional cost.
Connecting to Other Devices by Wire
All Smartphones have the ability to sync up with other devices. Syncing allows Smartphones to automatically make a back-up copy of all its files, recharge its battery, share files with the device it’s connected to, and update its email, calendar, notes and contacts. Syncing is a standard feature on all Smartphones.
In a process known as tethering, Smartphones can also be used to provide a laptop computer with a wireless internet connection.
Standard Phone Features
Each of the features listed below are usually built-in to your Smartphone or offered as a service by your wireless provider. How each of these features or services actually work varies from company to company and from handset to handset:
Caller ID
Automatic Redial
Call Waiting
Conference Calling
Call Muting
Speech Recognition & Voice Control
Speed Dialing
Contact List / Address Book (access to on-line and on-board phone numbers)
Hands Free Dialing (earpiece operations)
Hearing Aid Compatible
TeleTYpewriter (TTY) Compatible
Ports & Slots
Basic Device: one USB 1.1 port
Standard Device: one USB 2.x port; one 3.5mm stereo or one 2.5 mono headphone jack
Performance Device: two or more USB 2.x ports

Location Fixing

Location fixing is one of the underlying technologies that makes these devices Smartphones. The ability to geographically fix your planetary location and physical orientation allows all sorts of services and capabilities to be delivered into the palm of your hands. Assisted GPS (A-GPS), digital compasses and accelerometers are standard features on most current Smartphones.

Multi-media Technology

Several years ago, manufacturers began building digital cameras into their Smartphones. They were an immediate hit. As their popularity grew and competition increased, manufacturers introduced ever more sophisticated cameras with higher and higher pixel counts.
As data transmission speeds and chip processing power improved, manufacturers started building video capabilities into their cameras. About a year ago, manufacturers began building two video capable cameras into their Smartphones.
Today, it’s not uncommon for an average Smartphone to sport at least one 5 megapixel camera that’s capable of streaming DVD quality video. Advanced Smartphones usually come equipped with two, high resolution cameras that are capable of supporting HD video.
Graphics Processor Unit
Graphics Processing Units (aka GPU’s, Video Accelerators or Video Processors) were recently introduced into Smartphones to handle the computational demands of high resolution touch screens and digital video.
The GPU market is dominated by two different companies (i.e. PowerVR – a division of Imagination Technologies Group and Broadcom, Inc.). PowerVR supplies the “SGX” line of GPU’s. Broadcom supplies the “Adreno” line of GPU’s.
PowerVR uses the same business model as ARM Holdings (see the “Processor” section) in that it licenses its GPU designs to a variety of chip manufacturers. Broadcom on the other hand, produces its own GPU chips.
Standard Device: None
Performance Device: either PowerVR SGX or Broadcom Adreno chips.
Media Players
All Smartphones come with preinstalled software that enables it to play stored multimedia files like movies and music or live programming like streaming video or internet radio.
The media player software that comes with each Smartphone is often tied to its operating system. Despite this, it’s quite common for customers to swap out the preinstalled software for another media player of their choosing. Specific features vary from player to player.


Operating System
Smartphones run on operating systems that have been developed to accommodate the special technical needs of mobile phones. The most popular Smartphone operating systems include Apple’s iPhone OS, Google’s Android OS, Palm’s WebOS, RIM’s Blackberry OS, Nokia’s Symbian OS and Microsoft’s Mobile OS (a “skinny” version of its popular Windows OS). Linux is also used by a small number of other Smartphone manufacturers.
With the exception of the Microsoft product, all the operating systems listed are up-to-date and feature rich. They all have multi-touch interfaces; allow installation of 3rd party software and support multi-tasking operations.
Microsoft plans to replace its current Mobile OS with an up-to-date version by the end of 2010.
All Smartphones come with a large number of pre-installed software. Additional software can easily be downloaded and installed onto Smartphones from on-line stores at any time after the phone is purchased. These on-line stores are usually run by phone manufacturers, operating system developers or independent e-tailers.
Most Smartphones come with built-in software that allows you to view or edit most of the popular file types that are often attached to email messages. This is especially helpful for business users who are routinely called upon to review and edit business correspondence from their mobile device.

Here’s a list of software that’s usually preinstalled on most Smartphones.

  • Calendar
  • Notes
  • Calculator
  • Clock with built-in alarms
  • Syncing or backup software like iDisk, SugarSynch, Dropbox, MobileMe or
  • Office Productivity software like Google Docs, Microsoft Office (Excel, Word & PowerPoint), Apple’s iWork or DataViz’ Docs To Go.
  • File viewers like Adobe Acrobat (.PDF viewer)
  • eBook viewers like Amazon’s Kindle Reader, Microsoft’s Reader and Apple’s iBook Reader.
  • Email clients like Microsoft Outlook and Google Gmail
  • An Internet Browser like Google’s Android browser, Palm’s WebOS browser, RIM’s Blackberry browser, Microsoft’s Internet Explorer Mobile browser, Apple’s Safari browser and Open Software’s Opera Mobile browser.
  • On-line Search (including search by voice)
  • File compression software to compress and extract .ZIP files.
  • Built-in GPS, navigation and way-finding software (including maps and location search)
  • Video games.
  • Some high-end phones come equipped with facial recognition software.
eBook Reader Software
Some Smartphones come with eBook reader software pre-installed by the phone manufacturer or the wireless service provider. It is more common however for Smartphone customers to install eBook reader software for themselves.
Image Editing Software
Some Smartphones come with pre-installed image editing software that allows users to crop, rotate and geotag their digital photos.
Text-to-Speech (TTS) Software
Many new Smartphones come with software that reads certain text messages and alerts aloud. This feature is called Text-To-Speech (TTS). Hands free drivers and folks who are visually impaired find it especially useful.
TTS is a relatively new feature and most phone manufacturers are encouraging software developers to write software to significantly extend and enhance this capability. Given the initial popularity of TTS, we should expect to see such software come to market in the very near future.