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2012-03-07T03:57:00.001-08:00

Specifications of LCD:

Important factors to consider when evaluating an LCD:

Resolution versus range: Fundamentally resolution is the granularity (or number of levels) with which a performance feature of the display is divided. Resolution is often confused with range or the total end-to-end output of the display. Each of the major features of a display has both a resolution and a range that are tied to each other but very different. Frequently the range is an inherent limitation of the display while the resolution is a function of the electronics that make the display work.

Spatial performance: LCDs come in only one size for a variety of applications and a variety of resolutions within each of those applications. LCD spatial performance is also sometimes described in terms of a "dot pitch". The size (or spatial range) of an LCD is always described in terms of the diagonal distance from one corner to its opposite. This is an historical remnant from the early days of CRT television when CRT screens were manufactured on the bottoms of glass bottles, a direct extension of cathode ray tubes used in oscilloscopes. The diameter of the bottle determined the size of the screen. Later, when televisions went to a more square format, the square screens were measured diagonally to compare with the older round screens.

The spatial resolution of an LCD is expressed in terms of the number of columns and rows of pixels (e.g., 1024×768). This had been one of the few features of LCD performance that was easily understood and not subject to interpretation. Each pixel is usually composed of a red, green, and blue sub pixel. However there are newer schemes to share sub-pixels among pixels and to add additional colors of sub-pixels. So going forward, spatial resolution may be more subject to interpretation.

One external factor to consider in evaluating display resolution is the resolution of your own eyes. For a normal person with 20/20 vision, the resolution of your eyes is about one minute of arc. In practical terms that means for an older standard definition TV set the ideal viewing distance was about 8 times the height (not diagonal) of the screen away. At that distance the individual rows of pixels merge into a solid. If you were closer to the screen than that, you would be able to see the individual rows of pixels. If you are further away, the image of the rows of pixels still merge, but the total image becomes smaller as you get further away. For an HDTV set with slightly more than twice the number of rows of pixels, the ideal viewing distance is about half what it is for a standard definition set. The higher the resolution, the closer you can sit to the set or the larger the set can usefully be sitting at the same distance as an older standard definition display.

For a computer monitor or some other LCD that is being viewed from a very close distance, resolution is often expressed in terms of dot pitch or pixels per inch. This is consistent with the printing industry (another form of a display). Magazines, and other premium printed media are often at 300 dots per inch. As with the distance discussion above, this provides a very solid looking and detailed image. LCDs, particularly on mobile devices, are frequently much less than this as the higher the dot pitch, the more optically inefficient the display and the more power it burns. Running the LCD is frequently half, or more, of the power consumed by a mobile device.

An additional consideration in spatial performance are viewing cone and aspect ratio. The Aspect ratio is the ratio of the width to the height (for example, 4:3, 5:4, 16:9 or 16:10). Older, standard definition TVs were 4:3. Newer High Definition televisions (HDTV) are 16:9, as are most new notebook computers. Movies are often filmed in much different (wider) aspect ratios, which is why there will frequently still be black bars at the top and bottom of an HDTV screen.

The Viewing Angle of an LCD may be important depending on its use or location. The viewing angle is usually measured as the angle where the contrast of the LCD falls below 10:1. At this point, the colors usually start to change and can even invert, red becoming green and so forth. Viewing angles for LCDs used to be very restrictive however, improved optical films have been developed that give almost 180 degree viewing angles from left to right. Top to bottom viewing angles may still be restrictive, by design, as looking at an LCD from an extreme up or down angle is not a common usage model and these photons are wasted. Manufacturers commonly focus the light in a left to right plane to obtain a brighter image here.

Temporal/timing performance: Contrary to spatial performance, temporal performance is a feature where smaller is better. Specifically, the range is the pixel response time of an LCD, or how quickly you can change a sub-pixel's brightness from one level to another. For LCD monitors, this is measured in btb (black to black) or gtg (gray to gray). These different types of measurements make comparison difficult.Further, this number is almost never published in sales advertising.

Refresh rate or the temporal resolution of an LCD is the number of times per second in which the display draws the data it is being given. Since activated LCD pixels do not flash on/off between frames, LCD monitors exhibit no refresh-induced flicker, no matter how low the refresh. rate. High-end LCD televisions now feature up to 240 Hz refresh rate, which requires advanced digital processing to insert additional interpolated frames between the real images to smooth the image motion. However, such high refresh rates may not be actually supported by pixel response times and the result can be visual artifacts that distort the image in unpleasant ways.

Temporal performance can be further taxed if it is a 3D display. 3D displays work by showing a different series of images to each eye, alternating from eye to eye. For a 3D display it must display twice as many images in the same period of time as a conventional display and consequently the response time of the LCD becomes more important. 3D LCDs with marginal response times, will exhibit image smearing.

It is actually greater in your black and white vision (rod cells) than in color vision (cone cells). You are more able to see flicker or any sort of temporal distortion in a display image by not looking directly at it as your rods are mostly grouped at the periphery of your vision.

Color performance: There are many terms to describe color performance of an LCD. They include color gamut which is the range of colors that can be displayed and color depth which is the color resolution or the resolution or fineness with which the color range is divided. Although color gamut can be expressed as three pairs of numbers, the XY coordinates within color space of the reddest red, greenest green, and bluest blue, it is usually expressed as a ratio of the total area within color space that a display can show relative to some standard such as saying that a display was "120% of NTSC". NTSC is the National Television Standards Committee, the old standard definition TV specification. Color gamut is a relatively straight forward feature. However with clever optical techniques that are based on the way humans see color, termed color stretch,colors can be shown that are outside of the nominal range of the display. In any case, color range is rarely discussed as a feature of the display as LCDs are designed to match the color ranges of the content that they are intended to show. Having a color range that exceeds the content is a useless feature.
Color depth or color support is sometimes expressed in bits, either as the number of bits per sub-pixel or the number of bits per pixel. This can be ambiguous as an 8-bit color LCD can be 8 total bits spread between red, green, and blue or 8 bits each for each color in a different display. Further, LCDs sometimes use a technique called dithering which is time averaging colors to get intermediate colors such as alternating between two different colors to get a color in between. This doubles the number of colors that can be displayed; however this is done at the expense of the temporal performance of the display. Dithering is commonly used on computer displays where the images are mostly static and the temporal performance is unimportant.

When color depth is reported as color support, it is usually stated in terms of number of colors the LCD can show. The number of colors is the translation from the base 2-bit numbers into common base-10. For example, 8-bit, in common terms means 2 to the 8th power or 256 colors. 8-bits per color or 24-bits would be 256 x 256 x 256 or over 16 Million colors. The color resolution of the human eye depends on both the range of colors being sliced and the number of slices; but for most common displays the limit is about 28-bit color. LCD TVs commonly display more than that as the digital processing can introduce color distortions and the additional levels of color are needed to ensure true colors.

There are additional aspects to LCD color and color management, such as white point and gamma correction, which describe what color white is and how the other colors are displayed relative to white. LCD televisions also frequently have facial recognition software, which recognizes that an image on the screen is a face and both adjust the color and the focus differently from the rest of the image. These adjustments can have important effects on the consumer, but are not easily quantifiable; people like what they like and everyone does not like the same thing. There is no substitute for looking at the LCD one is going to buy before buying it. Portrait film, another form of display, has similar adjustments built in to it. Many years ago, Kodak had to overcome initial rejection of its portrait film in Japan because of these adjustments. In the U.S., people generally prefer a more colorful facial image than in reality (higher color saturation). In Japan, consumers generally prefer a less saturated image. The film that Kodak initially sent to Japan was biased in the wrong direction for Japanese consumers. Television monitors have their built-in biases as well.

Brightness and contrast ratio: Contrast ratio is the ratio of the brightness of a full-on pixel to a full-off pixel and, as such, would be directly tied to brightness if not for the invention of the blinking backlight (or burst dimming). The LCD itself is only a light valve, it does not generate light; the light comes from a backlight that is either a florescent tube or a set of LEDs. The blinking backlight was developed to improve the motion performance of LCDs by turning the backlight off while the liquid crystals were in transition from one image to another. However, a side benefit of the blinking backlight was infinite contrast. The contrast reported on most LCDs is what the LCD is qualified at, not its actual performance. In any case, there are two large caveats to contrast ratio as a measure of LCD performance.

The first caveat is that contrast ratios are measured in a completely dark room. In actual use, the room is never completely dark, as one will always have the light from the LCD itself. Beyond that, there may be sunlight coming in through a window or other room lights that reflect off of the surface of the LCD and degrades the contrast. As a practical matter, the contrast of an LCD, or any display, is governed by the amount of surface reflections, not by the performance of the display.

The second caveat is that the human eye can only image a contrast ratio of a maximum of about 200:1. Black print on a white paper is about 15–20:1. That is why viewing angles are specified to the point where they fall below 10:1. A 10:1 image is not great, but is discernable.

Brightness is usually stated as the maximum output of the LCD. In the CRT era, Trinitron CRTs had a brightness advantage over the competition, so brightness was commonly discussed in TV advertising. With current LCD technology, brightness, though important, is usually the same from maker to maker and is consequently not discussed much except for notebook LCDs and other displays that will be viewed in bright sunlight. In general, brighter is better, but there is always a trade-off between brightness and battery life in a mobile device.

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2012-03-07T03:50:00.000-08:00

What is LCD:
Liquid Crystal Displays (LCDs) are used to in flat-panel monitors and high-end flat-panel television. Recently, the market for LCDs has exploded as flat screen monitors and televisions have become popular consumer electronics devices. The manufacturing and sale of LCD devices has been profitable for a number of companies such as Chi Mei Optoelectronics, LG.Philips LCD, Samsung and Sharp Corporation (SHCAY) . However, continued competition has driven down panel prices and is threatening the profit margins on these displays at every point on the supply chain.

A number of companies depend on LCD panels for their earnings. They include
Corning (GLW) which both manufacture specialized, ultra-pure glass panels that are used by LCD panel manufacturers to make LCD displays, and are a major component of the company's earnings.
3M Company (MMM) and Tyco International (TYC) both manufacture specialized films used in LCD production.
Circuit City Stores (CC) and Best Buy (BBY) both rely on high profit margins for LCDs for their earnings.
Dell (DELL) sells a large quantity of LCD monitors with their computers.
Daktronics (DAKT), the leading manufacturer of digital signs and scoreboards, principally uses LCD screens.
Sharp Corporation (SHCAY), which develops, manufacturers, and sells LCDs for TVs and mobile phones.

A liquid crystal display (LCD) is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals (LCs). LCs do not emit light directly.

LCDs are used in a wide range of applications, including computer monitors, television, instrument panels, aircraft cockpit displays, signage, etc. They are common in consumer devices such as video players, gaming devices, clocks, watches, calculators, and telephones. LCDs have replaced cathode ray tube (CRT) displays in most applications. They are available in a wider range of screen sizes than CRT and plasma displays, and since they do not use phosphors, they cannot suffer image burn-in. LCDs are, however, susceptible to image persistence.

LCDs are more energy efficient and offer safer disposal than CRTs. Its low electrical power consumption enables it to be used in battery-powered electronic equipment. It is an electronically modulated optical device made up of any number of segments filled with liquid crystals and arrayed in front of a light source (backlight) or reflector to produce images in color or monochrome. The most flexible ones use an array of small pixels. The earliest discovery leading to the development of LCD technology, the discovery of liquid crystals, dates from 1888. By 2008, worldwide sales of televisions with LCD screens had surpassed the sale of CRT units.

Each pixel of an LCD typically consists of a layer of molecules aligned between two transparent electrodes, and two polarizing filters, the axes of transmission of which are (in most of the cases) perpendicular to each other. With no actual liquid crystal between the polarizing filters, light passing through the first filter would be blocked by the second (crossed) polarizer.

The surface of the electrodes that are in contact with the liquid crystal material are treated so as to align the liquid crystal molecules in a particular direction. This treatment typically consists of a thin polymer layer that is unidirectionally rubbed using, for example, a cloth. The direction of the liquid crystal alignment is then defined by the direction of rubbing. Electrodes are made of a transparent conductor called Indium Tin Oxide (ITO). The Liquid Crystal Display is intrinsically a “passive” device, it is a simple light valve. The managing and control of the data to be displayed is performed by one or more circuits commonly denoted as LCD drivers.

Before applying an electric field, the orientation of the liquid crystal molecules is determined by the alignment at the surfaces of electrodes. In a twisted nematic device (still the most common liquid crystal device), the surface alignment directions at the two electrodes are perpendicular to each other, and so the molecules arrange themselves in a helical structure, or twist. This induces the rotation of the polarization of the incident light, and the device appears grey. If the applied voltage is large enough, the liquid crystal molecules in the center of the layer are almost completely untwisted and the polarization of the incident light is not rotated as it passes through the liquid crystal layer. This light will then be mainly polarized perpendicular to the second filter, and thus be blocked and the pixel will appear black. By controlling the voltage applied across the liquid crystal layer in each pixel, light can be allowed to pass through in varying amounts thus constituting different levels of gray.

ww.kqzyfj.com/3977vpyvpxCIJGIHKECEDLHJMHG" target="_top" onmouseover="window.status='http://www.tomtom.com/?Lid=4';return true;" onmouseout="window.status=' ';return true;"> The optical effect of a twisted nematic device in the voltage-on state is far less dependent on variations in the device thickness than that in the voltage-off state. Because of this, these devices are usually operated between crossed polarizers such that they appear bright with no voltage (the eye is much more sensitive to variations in the dark state than the bright state). These devices can also be operated between parallel polarizers, in which case the bright and dark states are reversed. The voltage-off dark state in this configuration appears blotchy, however, because of small variations of thickness across the device.

Both the liquid crystal material and the alignment layer material contain ionic compounds. If an electric field of one particular polarity is applied for a long period of time, this ionic material is attracted to the surfaces and degrades the device performance. This is avoided either by applying an alternating current or by reversing the polarity of the electric field as the device is addressed (the response of the liquid crystal layer is identical, regardless of the polarity of the applied field).

Displays for a small number of individual digits and/or fixed symbols (as in digital watches, pocket calculators etc.) can be implemented with independent electrodes for each segment. In contrast full alphanumeric and/or variable graphics displays are usually implemented with pixels arranged as a matrix consisting of electrically connected rows on one side of the LC layer and columns on the other side, which makes it possible to address each pixel at the intersections. The general method of matrix addressing consists of sequentially addressing one side of the matrix, for example by selecting the rows one-by-one and applying the picture information on the other side at the columns row-by-row. For details on the various matrix addressing schemes see Passive-matrix and active-matrix addressed LCDs.

Active matrix technologies:

Twisted nematic (TN)

Twisted nematic displays contain liquid crystals that twist and untwist at varying degrees to allow light to pass through. When no voltage is applied to a TN liquid crystal cell, polarized light passes through the 90-degrees twisted LC layer. In proportion to the voltage applied, the liquid crystals untwist changing the polarization and blocking the light's path. By properly adjusting the level of the voltage almost any grey level or transmission can be achieved.

In-plane switching (IPS):

In-plane switching is an LCD technology that aligns the liquid crystals in a plane parallel to the glass substrates. In this method, the electrical field is applied through opposite electrodes on the same glass substrate, so that the liquid crystals can be reoriented (switched) in the same plane. This requires two transistors for each pixel instead of the single transistor needed for a standard thin-film transistor (TFT) display. Before LG Enhanced IPS was introduced in 2009, the additional transistors resulted in blocking more transmission area, thus requiring a brighter backlight and consuming more power, making this type of display less desirable for notebook computers. This newer, lower power technology can be found in the Apple iMac, iPad, and iPhone 4, the Hewlett-Packard EliteBook mobile workstations and the Nokia 701. Currently Panasonic is using an enhanced version eIPS for their large size LCD-TV products as well as Hewlett-Packard in its WebOS based TouchPad tablet.

IPS LCD vs AMOLED
LG claimed the smartphone LG Optimus Black with an IPS LCD (LCD NOVA) has the brightness up to 700 nits, while the competitor has only IPS LCD with 518 nits and double an Active-matrix OLED (AMOLED) display with 305 nits. LG also claimed the NOVA display to be 50 percent more efficient than regular LCDs and to consume only 50 percent of the power of AMOLED displays when producing white on screen. When it comes to contrast ratio, AMOLED display still performs best due to its underlying technology, where the black levels are displayed as pitch black and not as dark grey. On August 24, 2011, Nokia announced the Nokia 701 and also made the claim of the world's brightest display at 1000 nits. The screen also had Nokia's Clearblack layer, improving the contrast ratio and bringing it closer to that of the AMOLED screens.

Advanced fringe field switching (AFFS)

Known as fringe field switching (FFS) until 2003, advanced fringe field switching is similar to IPS or S-IPS offering superior performance and color gamut with high luminosity. AFFS was developed by Hydis Technologies Co., Ltd, Korea (formally Hyundai Electronics, LCD Task Force).

AFFS-applied notebook applications minimize color distortion while maintaining a wider viewing angle for a professional display. Color shift and deviation caused by light leakage is corrected by optimizing the white gamut which also enhances white/grey reproduction.

In 2004, Hydis Technologies Co.,Ltd licensed AFFS to Japan's Hitachi Displays. Hitachi is using AFFS to manufacture high-end panels. In 2006, HYDIS licensed AFFS to Sanyo Epson Imaging Devices Corporation.

Shortly thereafter, Hydis introduced a high-transmittance evolution of the AFFS display, called HFFS (FFS+).

Hydis introduced AFFS+ with improved outdoor readability in 2007. AFFS panels are mostly utilized in the cockpits of latest commercial aircraft displays.

Vertical alignment (VA)

Vertical alignment displays are a form of LCDs in which the liquid crystals naturally align vertically to the glass substrates. When no voltage is applied, the liquid crystals remain perpendicular to the substrate creating a black display between crossed polarizers. When voltage is applied, the liquid crystals shift to a tilted position allowing light to pass through and create a gray-scale display depending on the amount of tilt generated by the electric field.

Blue Phase mode:
Blue phase mode LCDs have been shown as engineering samples early in 2008, but they are not in mass-production yet. The physics of blue phase mode LCDs suggest that very short switching times (~1 ms) can be achieved, so time sequential color control can possibly be realized and expensive color filters would be obsolete. For details refer to Blue Phase Mode LCD.

Quality control:
Some LCD panels have defective transistors, causing permanently lit or unlit pixels which are commonly referred to as stuck pixels or dead pixels respectively. Unlike integrated circuits (ICs), LCD panels with a few defective transistors are usually still usable. Manufacturers' policies for the acceptable number of defective pixels vary greatly. At one point, Samsung held a zero-tolerance policy for LCD monitors sold in Korea. As of 2005, though, Samsung adheres to the less restrictive ISO 13406-2 standard.Other companies have been known to tolerate as many as 11 dead pixels in their policies. Dead pixel policies are often hotly debated between manufacturers and customers. To regulate the acceptability of defects and to protect the end user, ISO released the ISO 13406-2 standard. However, not every LCD manufacturer conforms to the ISO standard and the ISO standard is quite often interpreted in different ways.

LCD panels are more likely to have defects than most ICs due to their larger size. For example, a 300 mm SVGA LCD has 8 defects and a 150 mm wafer has only 3 defects. However, 134 of the 137 dies on the wafer will be acceptable, whereas rejection of the LCD panel would be a 0% yield. In recent years, quality control has been improved. An SVGA LCD panel with 4 defective pixels is usually considered defective and customers can request an exchange for a new one. Some manufacturers, notably in South Korea where some of the largest LCD panel manufacturers, such as LG, are located, now have "zero defective pixel guarantee", which is an extra screening process which can then determine "A" and "B" grade panels.Many manufacturers would replace a product even with one defective pixel. Even where such guarantees do not exist, the location of defective pixels is important. A display with only a few defective pixels may be unacceptable if the defective pixels are near each other.

LCD panels also have defects known as clouding (or less commonly mura), which describes the uneven patches of changes in luminance. It is most visible in dark or black areas of displayed scenes.

Zero-power (bistable) displays:

The zenithal bistable device (ZBD), developed by QinetiQ (formerly DERA), can retain an image without power. The crystals may exist in one of two stable orientations ("Black" and "White") and power is only required to change the image. ZBD Displays is a spin-off company from QinetiQ who manufacture both grayscale and color ZBD devices.

Kent Displays has also developed a "no power" display that uses polymer stabilized cholesteric liquid crystal (ChLCD). Kent has recently[when?] demonstrated the use of a ChLCD to cover the entire surface of a mobile phone, allowing it to change colors, and keep that color even when power is cut off.

In 2004 researchers at the University of Oxford demonstrated two new types of zero-power bistable LCDs based on Zenithal bistable techniques.

Several bistable technologies, like the 360° BTN and the bistable cholesteric, depend mainly on the bulk properties of the liquid crystal (LC) and use standard strong anchoring, with alignment films and LC mixtures similar to the traditional monostable materials. Other bistable technologies, e.g., BiNem® technology, are based mainly on the surface properties and need specific weak anchoring materials.

2012-03-07T03:39:00.001-08:00

Introduction to How LCDs Work

You probably use items containing an LCD (liquid crystal display) every day. They are all around us -- in laptop computers, digital clocks and watches, microwave ovens, CD players and many other electronic devices. LCDs are common because they offer some real advantages over other display technologies. They are thinner and lighter and draw much less power than cathode ray tubes (CRTs), for example.

But just what are these things called liquid crystals? The name "liquid crystal" sounds like a contradiction. We think of a crystal as a solid material like quartz, usually as hard as rock, and a liquid is obviously different. How could any material combine the two?

We learned in school that there are three common states of matter: solid, liquid or gaseous. Solids act the way they do because their molecules always maintain their orientation and stay in the same position with respect to one another. The molecules in liquids are just the opposite: They can change their orientation and move anywhere in the liquid. But there are some substances that can exist in an odd state that is sort of like a liquid and sort of like a solid. When they are in this state, their molecules tend to maintain their orientation, like the molecules in a solid, but also move around to different positions, like the molecules in a liquid. This means that liquid crystals are neither a solid nor a liquid. That's how they ended up with their seemingly contradictory name.

So, do liquid crystals act like solids or liquids or something else? It turns out that liquid crystals are closer to a liquid state than a solid. It takes a fair amount of heat to change a suitable substance from a solid into a liquid crystal, and it only takes a little more heat to turn that same liquid crystal into a real liquid. This explains why liquid crystals are very sensitive to temperature and why they are used to make thermometers and mood rings. It also explains why a laptop computer display may act funny in cold weather or during a hot day at the beach.

Nematic Phase Liquid Crystals

Just as there are many varieties of solids and liquids, there is also a variety of liquid crystal substances. Depending on the temperature and particular nature of a substance, liquid crystals can be in one of several distinct phases (see below). In this article, we will discuss liquid crystals in the nematic phase, the liquid crystals that make LCDs possible.

One feature of liquid crystals is that they're affected by electric current. A particular sort of nematic liquid crystal, called twisted nematics (TN), is naturally twisted. Applying an electric current to these liquid crystals will untwist them to varying degrees, depending on the current's voltage. LCDs use these liquid crystals because they react predictably to electric current in such a way as to control light passage.

Most liquid crystal molecules are rod-shaped and are broadly categorized as either thermotropic or lyotropic.

Thermotropic liquid crystals will react to changes in temperature or, in some cases, pressure. The reaction of lyotropic liquid crystals, which are used in the manufacture of soaps and detergents, depends on the type of solvent they are mixed with. Thermotropic liquid crystals are either isotropic or nematic. The key difference is that the molecules in isotropic liquid crystal substances are random in their arrangement, while nematics have a definite order or pattern.

The orientation of the molecules in the nematic phase is based on the director. The director can be anything from a magnetic field to a surface that has microscopic grooves in it. In the nematic phase, liquid crystals can be further classified by the way molecules orient themselves in respect to one another. Smectic, the most common arrangement, creates layers of molecules. There are many variations of the smectic phase, such as smectic C, in which the molecules in each layer tilt at an angle from the previous layer. Another common phase is cholesteric, also known as chiral nematic. In this phase, the molecules twist slightly from one layer to the next, resulting in a spiral formation.

Ferroelectric liquid crystals (FLCs) use liquid crystal substances that have chiral molecules in a smectic C type of arrangement because the spiral nature of these molecules allows the microsecond switching response time that make FLCs particularly suited to advanced displays. Surface-stabilized ferroelectric liquid crystals (SSFLCs) apply controlled pressure through the use of a glass plate, suppressing the spiral of the molecules to make the switching even more rapid.

Creating an LCD

There's more to building an LCD than simply creating a sheet of liquid crystals. The combination of four facts makes LCDs possible:
Light can be polarized. (See How Sunglasses Work for some fascinating information on polarization!)
Liquid crystals can transmit and change polarized light.
The structure of liquid crystals can be changed by electric current.
There are transparent substances that can conduct electricity.

An LCD is a device that uses these four facts in a surprising way.

To create an LCD, you take two pieces of polarized glass. A special polymer that creates microscopic grooves in the surface is rubbed on the side of the glass that does not have the polarizing film on it. The grooves must be in the same direction as the polarizing film. You then add a coating of nematic liquid crystals to one of the filters. The grooves will cause the first layer of molecules to align with the filter's orientation. Then add the second piece of glass with the polarizing film at a right angle to the first piece. Each successive layer of TN molecules will gradually twist until the uppermost layer is at a 90-degree angle to the bottom, matching the polarized glass filters.

As light strikes the first filter, it is polarized. The molecules in each layer then guide the light they receive to the next layer. As the light passes through the liquid crystal layers, the molecules also change the light's plane of vibration to match their own angle. When the light reaches the far side of the liquid crystal substance, it vibrates at the same angle as the final layer of molecules. If the final layer is matched up with the second polarized glass filter, then the light will pass through.

If we apply an electric charge to liquid crystal molecules, they untwist. When they straighten out, they change the angle of the light passing through them so that it no longer matches the angle of the top polarizing filter. Consequently, no light can pass through that area of the LCD, which makes that area darker than the surrounding areas.

Building a simple LCD is easier than you think. Your start with the sandwich of glass and liquid crystals described above and add two transparent electrodes to it. For example, imagine that you want to create the simplest possible LCD with just a single rectangular electrode on it. The layers would look like this:

The LCD needed to do this job is very basic. It has a mirror (A) in back, which makes it reflective. Then, we add a piece of glass (B) with a polarizing film on the bottom side, and a common electrode plane (C) made of indium-tin oxide on top. A common electrode plane covers the entire area of the LCD. Above that is the layer of liquid crystal substance (D). Next comes another piece of glass (E) with an electrode in the shape of the rectangle on the bottom and, on top, another polarizing film (F), at a right angle to the first one.

The electrode is hooked up to a power source like a battery. When there is no current, light entering through the front of the LCD will simply hit the mirror and bounce right back out. But when the battery supplies current to the electrodes, the liquid crystals between the common-plane electrode and the electrode shaped like a rectangle untwist and block the light in that region from passing through. That makes the LCD show the rectangle as a black area.

Backlit vs. Reflective

Note that our simple LCD required an external light source. Liquid crystal materials emit no light of their own. Small and inexpensive LCDs are often reflective, which means to display anything they must reflect light from external light sources. Look at an LCD watch: The numbers appear where small electrodes charge the liquid crystals and make the layers untwist so that light is not transmitting through the polarized film.

Most computer displays are lit with built-in fluorescent tubes above, beside and sometimes behind the LCD. A white diffusion panel behind the LCD redirects and scatters the light evenly to ensure a uniform display. On its way through filters, liquid crystal layers and electrode layers, a lot of this light is lost -- often more than half!

In our example, we had a common electrode plane and a single electrode bar that controlled which liquid crystals responded to an electric charge. If you take the layer that contains the single electrode and add a few more, you can begin to build more sophisticated displays.

Common-plane-based LCDs are good for simple displays that need to show the same information over and over again. Watches and microwave timers fall into this category. Although the hexagonal bar shape illustrated previously is the most common form of electrode arrangement in such devices, almost any shape is possible. Just take a look at some inexpensive handheld games: Playing cards, aliens, fish and slot machines are just some of the electrode shapes you'll see.

Passive and Active Matrix

Passive-matrix LCDs use a simple grid to supply the charge to a particular pixel on the display. Creating the grid is quite a process! It starts with two glass layers called substrates. One substrate is given columns and the other is given rows made from a transparent conductive material. This is usually indium-tin oxide. The rows or columns are connected to integrated circuits that control when a charge is sent down a particular column or row. The liquid crystal material is sandwiched between the two glass substrates, and a polarizing film is added to the outer side of each substrate. To turn on a pixel, the integrated circuit sends a charge down the correct column of one substrate and a ground activated on the correct row of the other. The row and column intersect at the designated pixel, and that delivers the voltage to untwist the liquid crystals at that pixel.
The simplicity of the passive-matrix system is beautiful, but it has significant drawbacks, notably slow response time and imprecise voltage control. Response time refers to the LCD's ability to refresh the image displayed. The easiest way to observe slow response time in a passive-matrix LCD is to move the mouse pointer quickly from one side of the screen to the other. You will notice a series of "ghosts" following the pointer. Imprecise voltage control hinders the passive matrix's ability to influence only one pixel at a time. When voltage is applied to untwist one pixel, the pixels around it also partially untwist, which makes images appear fuzzy and lacking in contrast.

Active-matrix LCDs depend on thin film transistors (TFT). Basically, TFTs are tiny switching transistors and capacitors. They are arranged in a matrix on a glass substrate. To address a particular pixel, the proper row is switched on, and then a charge is sent down the correct column. Since all of the other rows that the column intersects are turned off, only the capacitor at the designated pixel receives a charge. The capacitor is able to hold the charge until the next refresh cycle. And if we carefully control the amount of voltage supplied to a crystal, we can make it untwist only enough to allow some light through.

By doing this in very exact, very small increments, LCDs can create a gray scale. Most displays today offer 256 levels of brightness per pixel.

Color LCD

An LCD that can show colors must have three subpixels with red, green and blue color filters to create each color pixel.

Through the careful control and variation of the voltage applied, the intensity of each subpixel can range over 256 shades. Combining the subpixels produces a possible palette of 16.8 million colors (256 shades of red x 256 shades of green x 256 shades of blue), as shown below. These color displays take an enormous number of transistors. For example, a typical laptop computer supports resolutions up to 1,024x768. If we multiply 1,024 columns by 768 rows by 3 subpixels, we get 2,359,296 transistors etched onto the glass! If there is a problem with any of these transistors, it creates a "bad pixel" on the display. Most active matrix displays have a few bad pixels scattered across the screen.

LCD technology is constantly evolving. LCDs today employ several variations of liquid crystal technology, including super twisted nematics (STN), dual scan twisted nematics (DSTN), ferroelectric liquid crystal (FLC) and surface stabilized ferroelectric liquid crystal (SSFLC).

Display size is limited by the quality-control problems faced by manufacturers. Simply put, to increase display size, manufacturers must add more pixels and transistors. As they increase the number of pixels and transistors, they also increase the chance of including a bad transistor in a display. Manufacturers of existing large LCDs often reject about 40 percent of the panels that come off the assembly line. The level of rejection directly affects LCD price since the sales of the good LCDs must cover the cost of manufacturing both the good and bad ones. Only advances in manufacturing can lead to affordable displays in bigger sizes.

How to Buy a Laptop

2012-02-05T19:46:00.000-08:00

Introduction

The most highly evolved species of computer, the laptop (aka notebook) computer allows you to work without being tethered to an office. Portability and good performance make laptop PCs an essential part of the daily lives of millions of people, from college students to business travelers. Even the least-expensive of today's laptops are well equipped for everyday work.

The Big Picture
There are more laptop choices than ever. We'll identify and discuss the available options--including screen size, weight, battery life, and communications ports.

The Specs Explained
Do you need a superfast CPU? Or a huge hard drive? We'll guide you through the choices and tell you which features are most critical.
The Big Picture

If you've ever shopped for a laptop, you know that the factors to consider go far beyond performance and connections. Notebook buyers have to think about such additional variables as size, weight, screen dimensions, battery life, and keyboard quality--plus options such as built-in wireless.
Key Features

Processor: Intel's dual-core processors have helped laptops gain ground in the power department. In PC World tests, laptops using these dual-core processors performed considerably faster than laptops using single-core processors, particularly when multitasking. In newer notebooks you may see references to Core Duo, Core 2 Duo, and Core 2 Extreme, which represent steps up in computing power for laptops.

Some notebooks use AMD's Athlon Turion 64 X2 dual-core processor, which also supports improved performance. The Turion 64 X2 and the Core 2 Duo both provide 64-bit support, which will become increasingly useful as more 64-bit applications reach the market.

Low-end laptops offer Intel's Celeron M processor, which is generally not as speedy as the Core 2 Duo processors. And down below low-end are the new mobile processors that appear in netbooks (or mini-notebooks)--sub-$500 machines that run on low-power, low-cost 1.6-GHz Atom CPUs.

System memory: Unless you're buying on the cheap, a new laptop generally includes 2GB of system memory. Many notebooks today are available with 3GB of RAM or more. Before electing to upgrade to more RAM than that, be sure to check which version of Windows your new notebook uses. A 32-bit OS can't efficiently use more than 3GB of RAM. A 64-bit version can go higher. Outfitting your laptop with more RAM at the time you buy it is convenient and helps you extend its useful life.

Graphics memory: Portables can have either of two different types of video chip sets: dedicated video (which means a separate preinstalled graphics card) or integrated graphics. Dedicated video chip sets come from nVidia and ATI/AMD, whereas integrated graphics are typically from Intel. If you intend to use your laptop for even casual gaming, make sure that it has memory dedicated to graphics use, rather than relying on graphics that pull from main memory. Gamers need advanced 3D graphics chips, along with 512MB of dedicated graphics memory. High-end desktop-replacement notebooks have sophisticated desktop graphics capabilities, as well; in the past integrated graphics would work just fine for business purposes, but Windows Vista demands a more-powerful graphics subsystem.

Some laptops now offer Scalable Link Interface (SLI), which provides a means to run multiple graphics chips in one machine. Hybrid SLI, a technology offered by nVidia, involves two GPUs operating within a single notebook. The most basic version of Hybrid SLI already exists on Apple's new MacBook Pro laptop and on a couple of notebooks from Sony's VAIO line. With these machines you toggle between a high-powered discrete GPU for graphics-intensive work or play and an integrated GPU on the motherboard for low-demand graphics. A second implementation of Hybrid SLI will allow an integrated GPU, like nVidia's GeForce 9400M GS, to work in tandem with a discrete GPU for greater performance when needed--and then downshift to a lower-power mode when it isn't.

Screen: Some laptop screens continue to get bigger--and most have gone wide, too, enabling you to view spreadsheets or movies with ease. But other screens have gotten significantly smaller to accommodate all sorts of road-ready computing. Price is no longer much of a deterrent for any of these choices. Even budget shoppers can afford the luxury of high-resolution color: Portables with 14.1-inch and 15.4-inch wide screens now cost well under $1000. Most notebook manufacturers offer laptops with wide-screen panels, to permit better side-by-side document viewing as well as to display films at their proper aspect ratio. These days, netbooks come equipped with screens as large as 10.2 inches. Ultraportable notebooks max out at 13.3 inches. And anything between 13.3 and 17 inches qualifies as an all-purpose machine--a laptop that still fits in your bag. The new middle ground for all-purpose screens is 16 inches because screen of this size can display a true 1080p (1920-by-1080-pixel resolution) picture.

Battery: Laptop battery life continues to improve. In PC World's tests, laptops using a Core Duo or Core 2 Duo processor average roughly 3.5 hours on one battery charge. Keep in mind that manufacturers may improve their times by taking steps such as turning off wireless receivers, which tend to consume a lot of power. Also, check to see if the manufacturer's stated battery-life numbers are for its regular or extended-life battery--the latter kind of battery can last up to twice as long as a regular one. And remember that, in general, lighter laptops tend to have longer battery lives than big desktop-replacement notebooks do.

Keyboard and pointing device: Though you can get accustomed to almost any laptop keyboard, it's best to try before you buy. Thin-and-light notebooks usually have smaller-than-average keys spaced more closely than the keys on a desktop-replacement model, and their layouts may differ from a standard keyboard's. If you have largish hands, be aware that an ultraportable's keyboard may be difficult to use.

You probably won't be invited to choose between eraserhead and trackpad pointing devices; if you have a preference, look for manufacturers that use the pointing device you prefer on most of their products. A better option: Buy a USB mouse designed for laptops. It's a small investment, and your hands will thank you for it.

Optical and other drives: Most manufacturers offer laptops with rewritable DVD drives. But now that Blu-ray Disk has triumphed over HD DVD in the high-definition format wars, more notebooks are being configured with Blu-ray drives. If you need a floppy drive for some reason, you can buy a USB add-on drive for 20 bucks.

Hard drive: Even inexpensive netbooks now come with 60GB hard-disk drives (HDDs). Most all-purpose machines offer hard drives in the range of 200GB to 320GB, and ultraportables now pack solid-state drives (SDDs). Though SDDs are faster and lighter than HDDs, their capacities are considerably lower (maxing out at around 128GB) at a significantly higher cost. In today's market, an SSD adds about $1000 to a laptop's price tag over the cost of a similarly specced machine equipped with a larger-capacity platter-based drive. So, you need to balance speed and weight against price and storage capacity. Whichever choice you make, you'll find that hard-drive space fills up quickly, so you might want to consider buying a portable external drive as well.

Weight and bay design: Laptops range from 15-pound desktop replacement monsters to ultraportable lightweights that rely on external drives to come in at under 3 pounds. One-bay notebooks balance features and weight. Some laptops continue to offer the optical drive as a modular device, so you can swap it out for a second hard drive or a second battery.

When making a purchase, however, keep in mind that you should consider the weight not only of the laptop but also of the AC adapter, the extra batteries, any external modules, and their cables. Ultraportable notebooks have lightweight adapters, but they can weigh almost as much as a full-size notebook if you have to carry an external optical drive, too.

When you return to your desk, you can snap most laptops onto an extra-cost docking station or port replicator (prices range from $100 to $500). Doing so saves you from repeatedly having to plug in and unplug an external monitor, keyboard, mouse, and other desktop peripherals.

Communications: Few laptops come with a full set of legacy ports anymore. Serial ports are as rare as bigfoot sightings at this point, as are PS/2 ports (for a mouse or keyboard). Most notebooks still have one PC Card slot, though many now offer an ExpressCard slot as well. With new GPUs, many notebooks--and even some netbooks--now offer HDMI outputs.

Most laptops have at least two USB 2.0 ports; many offer four, and some up to six. A majority of notebooks include a four-pin FireWire (IEEE 1394) port for connecting an external drive or a digital-video camcorder. Others now include eSATA ports for high-speed data transfers.

Built-in ethernet now comes standard on all portables, with many models carrying gigabit ethernet. Many laptops also have built-in Bluetooth. Notebooks using the Intel Core Duo or Core 2 Duo processors--or AMD's Turion 64 X2 processor--include Intel's wireless 802.11a/b/g chip set.

Some laptops come with built-in wireless broadband wide-area networking, enabling them to access, for example, Verizon Wireless's EvDO Broadband Access service.

Most also include a multiformat flash card reader, which can read Secure Digital, MultiMediaCard, Memory Stick, Memory Stick Duo, and xD formats.

The Specs Explained

Before shopping for a laptop, consider how you'll be using it. If your primary goal is to get some word processing or spreadsheet work done while staying on top of e-mail, a netbook (priced at less than $500) will meet your needs. But a netbook does entail some sacrifices: a smaller processor, about 1GB of RAM, not much in the way of hard drive space, no optical drive, and (at biggest) a 10.2-inch screen. On the surface not much separates the netbooks from sexy lightweight notebooks, but the specs under the hood (and a big screen inside it) can inflate an ultraportable's price to as much as $2000 more than a typical netbook.

Remember that most vendors let you custom-build and -price your own laptop by picking from a mind-boggling array of features, which gives you a lot of control over the final product. You may be able to afford a faster notebook by accepting a smaller, less-expensive hard drive or DVD-ROM/CD-RW drive, instead of a BD-ROM.

Unlike those on desktop PCs, only some of the components (such as memory and the hard drive) are upgradable; others (such as the graphics board) are permanent once they're installed at the factory. That's slowly changing, as some manufacturers begin to incorporate upgradable graphics. But take your time and pick only what you need. Following is a rough breakout of some configuration options.

Important consideration: Installed memory. The more installed memory your laptop has, the more applications you can run at once, and the better your machine will perform. Ease of access aside, upgrading memory in a notebook is a bit trickier than with a desktop, so buy as much memory preinstalled as you can afford. Laptops with 2GB of RAM are optimal. If you're running Windows Vista on a laptop, consider upgrading to 3GB of RAM

Important consideration: Processor. The CPU determines how quickly a notebook runs applications and performs on-screen tasks. Core Duo and Core 2 Duo processors are good choices for speedy processing. Atom processors appear only in budget-friendly netbooks, so plan according to your needs.

Important consideration: Screen size. The specified size of a laptop's LCD screen represents a diagonal measurement. The larger the screen, the higher the maximum resolution and the more information you can view at once. At this point, most notebooks are wide-screen models; if you want a laptop with a standard-aspect screen you'll have to search a bit, but they are still available. The aspect ratio seen on some newer 16-inch laptop screens offers the ideal resolution for viewing high-definition movies on the go. (Compare laptops with recommended screen sizes.)

Important consideration: Screen coating. A laptop's LCD panel is only as good as it looks when you look into it. Can you see text and images clearly when you're viewing them in broad daylight? Many notebooks that look sharp on store shelves (thanks to their extra-glossy coatings) may be tough to work with outdoors or in a coffee shop. So keep in mind not only how you plan to use your notebook, but where you want to use it.

Somewhat important: Hard drive. The larger the hard drive, the more data you can keep on your laptop. Most cheap netbooks offer 80GB drives at this point, so why not give yourself a little room to grow? If you plan to work with databases, spreadsheets, or digital photo or video files, opt for a large drive. Be sure to find out the hard drive's speed, too. Older, slower drives run at 4200 rpm, and most current drives clock in at 5400 rpm; but a 7200-rpm model will offer better speed in data-read-intensive tasks.

Somewhat important: Expansion bays. The more expansion baysyour laptop has, the more options you'll have for switching in new optical drives or other storage drives. But switching drives takes time, and modular components aren't as common as they used to be. As laptops gravitate toward flush form factors and unibody designs, may find that your only practical option is to lug around external drives that plug in through USB ports.

Somewhat important: Optical drives. Most manufacturers offer laptops with rewritable DVD drives, which give you the most flexibility. Alternatively, you could purchase a notebook with a DVD-ROM/CD-RW drive, to save money.

Evaluate Mobile Phone Features

2012-01-31T19:10:00.000-08:00

On eBay Australia, the vast selection of new and used mobile phones means that you should be able to find a phone in any shape, size and price category. If your mobile phone needs are quite basic, you can dispense with the all the bells and whistles associated with some of the higher cost models. If cost is not an issue, you will find a one-stop-shop for all the latest and greatest in mobile phone technology from around the world.

The options to consider when shopping for a mobile phone are often confusing, and new features for mobile phones grow day by day. To narrow your search, think about the following key questions:

Do you plan to use your mobile phone outside of your local area?

If you plan on using your phone outside of Australia, you may want to choose a Tri Band GSM phone that is able to operate across three GSM (Global System for Mobile Communications) frequencies. GSM is the standard network type utilised around the world. If you are not planning using your phone internationally, then a standard GSM phone is generally sufficient within a metropolitan area.

Alternatively, a CDMA network may suit your needs. CDMA in particular is ideal for users in rural and regional areas due to its coverage over longer distances. This network is also used in North America.

Would you like access to the internet or email from your mobile phone?

Many mobile phones and service providers now offer email and internet access. If you require this functionality, ensure that the model you are interested in is email and/or web-enabled.

Additional Features

The latest model of phones now come with a host of additional features that can further simplify (or perhaps even complicate!) your search. Some features now available include: built-in camera , rc_done="true">colour screen , PDA , Email/Web ,unlocked , MP3 players , speaker-phone, walkie-talkie, voice-activated calling and games.

How important is your phone's size and weight?

Functionality and fashion seem to go hand in hand and we now have a vast selection of shapes, sizes and weights to choose from. The main varieties and their comparative advantages include:

Candybar (Standard) : Simplicity and durability.
Slide : Soft slide mechanism that smoothly reveals and hides keypad of phone.
Clamshell (flip-phone) : Portability, increased screensize, keys protected against accidental dialling.
PDA : Larger silhouette, increased screensize and functionality.

Select a Mobile Phone Service Provider
Service providers work with specific mobile phone manufacturers to produce phones that are compatible with their networks and feature offerings. On eBay Australia, you will find phones for every major service provider. There are also phones ready to be connected with a new service plan, prepaid phones or prepaid starter kits for those who want no plan at all.

Australian Service Providers
If you already have a service contract with a carrier and are not looking to change from your service provider, then a new mobile phone that is unlocked (ie. will work for any service provider) may be what you need.
The major service providers within Australia that offer mobile phone plans and prepaid sim cards are:
- Telstra
- Orange
- Optus
- Virgin Mobile
- Vodafone
- 3
Pre-Paid Services
If you want the convenience of a prepaid service , there are specific phone models which are available for use with prepaid phone cards. Search through the prepaid section and find the right choice for you. You may also want to find out more about prepaid phones with SIM cards , prepaid recharge cards or prepaid SIM starter kits .

Coverage
Once you have narrowed the search of the mobile phones that you are interested in down to just a few, you may want to confirm with your desired service provider that they can provde the coverage you require in your specific geographic area.

Buy with Confidence
Before making your purchase, make sure you know exactly what you're buying, research your seller, and understand how eBay Australia and PayPal protect you.

Carefully read the details in item listings.
- Figure delivery costs into your final price. If you spend a lot of money, make sure the seller will insure the item when it ships.
- If you want more information, ask by clicking the "Ask seller a question" link under the seller's profile.
- Always make sure to complete your transaction on eBay Australia (with a bid, Buy It Now, or Best Offer). Transactions conducted outside of eBay Australia are not covered by eBay Australia protection programs.
- Never pay for your eBay Australia item using instant cash wire transfer services through Western Union or MoneyGram. These payment methods are unsafe when paying someone you do not know.
Know your seller
Research your seller so you feel positive and secure about every transaction.
- What is the seller's Feedback rating? How many transactions have they completed? What percentage of positive responses do they have?
- What do buyers say in their Feedback? Did the seller receive praise?
- Most top eBay Australia sellers operate like retail stores and have return policies. Do they offer a money-back guarantee? What are the terms and conditions
  
  Legal Disclaimer
  Buying Guides are intended merely as a guide or review for members when considering what products or services they may be interested in bidding on or purchasing. eBay Australia does not make, and nothing in these Buying Guides is intended to constitute, any warranties, guarantees, representations or assurances about the accuracy of the information or content contained in these Buying Guides. Furthermore, eBay Australia does not make, and nothing in these Buying Guides is intended to constitute, any warranties, guarantees, representations or assurances about the nature or performance of the products or services appearing in the Buying Guides. eBay Australia is not affiliated with nor does it endorse the use of any particular product or service.

Cell Phone Buying Guide 2010

2012-01-31T19:08:00.000-08:00

We outline some of the most important factors to look into when purchasing a new cell phone.

When your old cell phone squeaks like a rusty door hinge, has more lint under the screen than your jean pockets, and lasts half an afternoon with a full charge, it’s time for a new one. But with most cell phone contracts lasting two years, a new phone shouldn’t be the type of purchase you make lightly. Check out our quick and dirty guide to your next phone purchase to make sure you cover all the bases on your shopping trip.

Choosing a carrier

Because most U.S. cell phone carriers heavily subsidize phone purchases in exchange for two-year contracts, and lock the phones to their networks, your choice of cell carrier will have more impact on which type of phone you end up with than any other factor. If you already have carrier and feel satisfied with it, the choice is easy. If not, you’ll need to choose one.

AT&T, T-Mobile, Sprint, and Verizon dominate the cell phone market in the States. Speaking in very general terms, AT&T has a reputation for having the hottest phones but somewhat flaky service due to its overloaded towers, Verizon has the best reception but expensive rates, T-Mobile offers excellent voice plans but has very limited 3G data coverage, and Sprint sells some of the most affordable plans but typically doesn’t offer as many popular phones.

Prepaid carriers like Cricket, Tracfone, and MetroPCS often appear to offer excellent deals, but caveats like poor customer service, limited phone selection and inferior coverage have to be taken into account. Check out our guide to prepaid cellular plans for information on prepaid carriers, andour listing of some of the best if you decide to take that route.

The difference between a smartphone and a feature phone

You could divvy up cellphones into dozens of different categories, but these are the two umbrella groups that matter. Smartphones like the iPhone can serve as personal calendars, e-mail machines, Web browsers, gaming platforms, and a literally unlimited number of other purposes. They’re essentially mini computers. Feature phones are more basic, but they still offer features like cameras, text messaging, and even some limited data connectivity, like checking weather or sports scores. Although smartphones obviously have a lot to offer, they also weigh more, offer less battery life,

Different form factors

Even after choosing between a smartphone or feature phone, you have a lot of choices to make to decide what your phone will actually look like.

A full touch layout like the iPhone has become popular for smartphones, but you’ll usually forgo a hard keyboard as a result. Some smartphones like the Palm Pre or HTC Touch Pro2offer a slide-out keyboard as a compromise, but get thicker as a result, too. Many smartphones also dupe the popular BlackBerry design: small screen on top, small keyboard below.

In feature phones, the flip or “clamshell” form factor has proven especially popular because of its small size and the fact that it protects the screen and keys when closed. Phones with both the screen and keypad on a fixed rectangular slab are typically called “candybar” phones. As with smartphones, you’ll many feature phones with dedicated QWERTY keyboards, which can be handy for frequent text messagers.

How to Buy a Cell Phone

2012-01-31T19:06:00.001-08:00

There's no sense in denying it: For most of us, mobile phones are at the center of our universe. It's your phone, your messaging device, your on-the-go Web browser, your camera, your music player, your GPS navigation unit—and soon, with NFC technology, it could even be your wallet.

If you thought choosing a cell phone was difficult before, it's even tougher today. That's a good thing, though, because it demonstrates how innovation in the wireless industry has skyrocketed. We're seeing rapid progress across all fronts, including displays, data networks, user interfaces, voice quality, third-party apps, and even mobile gaming.

To cite just a few examples: All four major U.S. carriers now offer some variation of 4G networks, which (depending on the carrier and technology used) is anywhere from two to 10 times faster than 3G. The latest crop of Android smartphones is more diverse and powerful than ever; Android is also far and away the sales leader in the U.S. when it comes to smartphones, a result few could have predicted just two years ago. Apple's game-changing iPhone 4S—itself a technological marvel—is available on Verizon Wireless and Sprint in addition to AT&T, opening up access to another 150 million customers. Standard "feature" phones (handsets without app-based ecosystems) are beginning to fade in importance and sales are trending downward.

Taken together, these massive changes make much of the old advice about choosing a phone obsolete. So let's throw it all away and start over. The topic has become so important, and involves so many decisions, that we scrapped our existing cell phone and smartphone buying guides in favor of a single comprehensive story—the one you're reading right now.

So what should you be looking for when buying a cell phone? Here are some key points to consider:

-width: 0px; border-color: initial; border-image: initial; border-left-width: 0px; border-right-width: 0px; border-style: initial; border-top-width: 0px; font-family: inherit; font-style: inherit; font-weight: bold; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; outline-color: initial; outline-style: initial; outline-width: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px; vertical-align: baseline;">First, Choose a CarrierDespite all the recent hardware and mobile software innovation, your wireless service provider remains your most important decision. No matter which device you buy, it's a doorstop unless you have solid wireless coverage. Maybe you have friends and family on the same carrier that you talk to for free, and you don't want that to change with your next phone. Maybe you're lusting after a certain device—say, a 4G LTE-capable Android phone, or an unlocked smartphone for international travel. And of course, you want to choose a carrier that offers fair prices, and provides the best coverage in your area. These are all good reasons to put the carrier decision first.

We have two major features to help you choose a carrier. For our Readers' Choice Awards, more than 10,000 PCMag.com readers told us which carrier they prefer based on coverage, call quality, device selection, and other factors. And for our 2011 Fastest Mobile Networks feature, we sent drivers to 21 U.S. cities to scope out which smartphone carriers have the best data coverage. Because each of the national carriers sells a wide variety of phones, choosing your service provider should be your first move. Here's a quick rundown of what each one offers:

AT&T boasts nationwide coverage and a terrific selection of phones, particularly for texting. It has dramatically improved its service quality in the Northeast over the past two years, and is now powering up its 4G LTE network for the first time. It's also the worst-rated carrier by our readers. Sprint is relatively inexpensive, and offers some neat media services and a solid high-speed network. It also has the most open approach to third-party apps, letting its subscribers add a wide range of Java applications to its feature phones. Sprint has two prepaid brands, Virgin Mobile and Boost Mobile, that sell phones without contracts.

T-Mobile offers mostly cutting-edge phones at relatively low monthly rates and enjoys a reputation for good customer service. It's the only carrier that offers a monthly discount in exchange for paying full price for your phone up front. But its network can be weaker than the other major carriers' in suburban and rural areas. Verizon Wireless is famed for its top-notch network quality and good customer service. Its prices can be higher than the competition, but when it comes to voice quality, Verizon phones often excel. That makes Verizon a perpetual leader in our Readers' Choice Awards. Verizon also currently has the largest 4G LTE network in the U.S.

There are also smaller, regional carriers. U.S. Cellular is only available in about half the country, yet it consistently gets great scores on our Readers' Choice Awards because of its strong commitment to customer service. Last year the carrier launched the "Belief Project," a new customer-service plan offering perks like free battery swaps and replacements for damaged phones. Meanwhile, Cricket and MetroPCS are "unlimited" carriers that offer much lower rates than their competitors and don't require contracts. But they aren't available everywhere, and have a somewhat limited, mostly lower-end selection of phones.

Tips for buying and giving a mobile device

2012-01-31T19:05:00.000-08:00

What does my rate plan cover? Basically you are going to want to know if you will have unlimited text messages (essential these days I think), how many minutes you will be allowed if there are any overage fees for going over your plan limit, etc.
What kind of speeds/data am I getting? Will it be important for you to get information to your phone at lightning fast speed? Maybe you want to hook your laptop up to the phone, so you can use the internet wherever you are. Speed will be very important for you in that case. If you won’t be a heavy internet user on your phone, it will be less essential, obviously. T-Mobile has a great calculator for you to check out http://www.t-mobile.com/Tools/MBCalculator.aspx
What is the exchange/return policy? Sometimes a phone can be like getting married to someone you met on the internet. You really don’t know the phone until you pick it up and actually use it. Maybe after you’ve used it for a few days, it just doesn’t feel right in your phone, or the volume button keeps getting in your way. Whatever it is, you should have an escape clause!

How much will my monthly payments/charges be? You will for sure need to know if you are going to be able to pay your bill every month!
What are roaming charges? Roaming charges can occur when you are out of range of your network. Once (many years ago) I came to Utah for Thanksgiving, and my husband was still home, we chatted often on our cell phones, not realizing I was racking up some serious roaming charges. A $500 bill later, you learn to ask about these things.
What are your warranty/insurance policies? I’ve dropped many-a phone. Sometimes in the toilet, sometimes in a parking lot, and sometimes the phone just doesn’t work right out of the box. Whatever it is, even though sometimes you can get a phone for super cheap, the actual phone is much more expensive. Buying one while you are still within your 2 year contract can be super expensive. Cover yourself, and make sure you know what you can do when things go wrong.

T-Mobile has some great contract free plans as well. I know my sister’s family has been on a pre-paid plan for YEARS, and they are incredibly happy with it. So if you don’t want to get locked into a contract, T-Mobile has great options for you, but you may have to pay a bit more for a phone up front, but if you don’t use it much, you may end up saving BIG!

Are you buying your teenager their very first phone this year? T-Mobile has some great tools for you and for them to help make sure they aren’t abusing the privilege.

e-type: square; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px;">DriveSmart Plus-Distracted driving is dangerous, especially with new drivers. DriveSmart manages distractions by silencing incoming notifications, sending callers to voicemail and auto responding to text messages. There is automatic driving detection and parents parental control options. (including notification of cell phone use while driving)

Cell Phone Buying Guide

2012-01-31T19:03:00.001-08:00

The cell phone industry is complicated because customers' needs are so complicated. Cell phoneshopping doesn't need to be painful. It can actually be a lot of fun when you're not being pressured by a pushy phone salesman! This cell phone buying guide will give you some useful information, so you can purchase the right one on your own.

What You Need to Know:

Sound quality and reception: The most important characteristics of any cell phone are good sound quality and reception. Nothing's worse than having to end a conversation prematurely because of bad reception, especially if you have to do it over and over again. You might want to try a mobile phone with an external antenna for the best reception. Also, signal strength depends on your signal provider, so do your research before purchasing a cell phone plan.
Business use: PDA cell phones, also called smart phones, are popular for professionals. They mix schedulers, e-mail and other office programs into a compact device you can use at home, in the office or on the go. Many smart phones feature qwerty keyboards, smaller versions of what you'd find on your laptop. You should also consider the appearance of a phone for business purposes. A sleek black or silver phone might look a little more professional than a bright pink discount cell phone, but then again, that all depends on your type of business.

Kids and teens: If you're buying mobile phones for your children or teenagers, you don't want to get cheap cell phones, but you may want to think twice about certain features. Do you want them using their phones to log on to the Internet? You'll be charged for it, usually by the minute or data downloaded, which will cost an arm and a leg if used excessively! Will cell phone games be a distraction during school? Don't get any extra features if you'd rather they didn't use them.
Make it your own: Since practically everybody has one, you need to turn your cell phone into something unique. Whether you get a hard plastic case or a padded leather case, you can protect your phone and make it look cool all at the same time.

HOW TO CHOOSE THE RIGHT CELL PHONE

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Even though it's tempting to just buy the coolest phone , it's more important to start with choosing a carrier. Each cell phone carrier and service provider offers a different suite of technologies. Do you need international calling? That will eliminate several carriers. Are you looking for an unlimited plan? That will narrow the field further.

When you select a carrier, you will be expected to commit to a one- or two-year contract that details the service they will provide to your phone at the rate plan that you choose. Make sure you read the fine print; once you sign the contract, there are usually hefty fees for canceling it early. Along with the contract, the carrier will provide your initial phone purchase. Many providers sell phones at a discounted rate or offer some models free with a new contract. Watch for sales and promotions, which often occur when a new model is released. While many carriers offer pre-paid services, in the long run you'll end up paying much more for your phone and your service than you would with a monthly plan.

Choose a plan

The rate plan you choose will determine how many minutes you receive each month for text and talking, additional charges for extra minutes, cost of service features and data usage and more. Each carrier offers several rate plan packages, including individual and family plans. It's important to note that, regardless of which carrier or plan you choose, your first monthly bill will be much higher than subsequent months because you pay a number of enrollment and setup fees up-front. After that first month, though, keep an eye on your bill and how many minutes you and your family are using. Your carrier should allow you to adjust your plan up or down once you get a feel for what you really need.

Choose a technology

Cell phones come in two basic types: conventional and smart. Conventional cell phones often come free with a new contract. Typically, conventional phones are smaller than smart phones and are available at lower price points. While they include the basics — calling and texting — many come with add-ons like a camera, games or an internet connection. Smart phones build on those basics with applications like email, calendar, games and more. Some smart phones support Office documents, allowing you to work in programs like Word and Excel right from your phone. In general, smart phones browse the web faster than conventional phones and can be connected to several email accounts, including your business account. With a smart phone, you can also choose from thousands of downloadable applications that include everything from card games to productivity suites.

Cell Phone Buying Guide

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You’re confronted with literally thousands of choices when choosing a cell phone. Which phone should you go for? Which network should you go with? Which calling plan should you pick? Do you need the extra features the cell phone companies tempt you with? These choices may seem overwhelming, but it's not as difficult a choice as it may appear. Here's how to make the choices to get the right network, cell phone, and calling plan for you.

Choosing a network
The first choice might surprise you; rather than choose a cell phone, start by deciding which cell phone network to go with. The major factor here is coverage: does the network work where you are? Each network offers maps on their websites where you can enter your address to see if their network covers it; use this feature. Don't just check your home address; check your work and the places you visit regularly, because you'll be using your phone on the road.

If your preferred network doesn't cover your home, cross it off the list, because the carrier probably won't want to sell you a phone. But don't discount a network if one location you visit occasionally isn't covered; the networks have arrangements that let a customer of one network temporarily use another, (called roaming), although this may sometimes involve extra cost. Make a note of this and remember to check the roaming cost when you pick a calling plan.

You should also remember that loyalty is overrated; you don't have to stick with your existing network if you want to switch. If you have a cell phone and want to keep the number, you can transfer the number to a different network, a process that usually takes only a few hours. The networks call this number porting, and that way, you can switch carriers but not lose your number. The main gotcha with this is making sure your old network doesn't hit you up for an early termination fee. Because switching networks involves ending your contract with your old carrier, they will often try and charge you for ending the contract if it isn't finished (most contracts last two years). If you aren't sure, call your carrier before you switch and ask them how long the contract is, and what their early termination fee is. If they think you are planning on leaving them, they might give you a month or two of free service to persuade you to stay.

Another factor to consider is whether or not a lot of people you call use a particular network. Some networks offer free calls to phone numbers on the same network. Again, you should make sure this feature is included when you get to the calling plan if that's an important factor for you.

Choosing a phone
The first step in choosing a cell phone is deciding which type is right for you. Here are the different types and the pros and cons of each.

Candybar – The simplest phones, candybar phones such as the BlackBerry Pearl have a screen and keypad on the outside. While this simplicity means they are usually cheap, they only have keypads with number keys, which makes typing e-mails a slow process. The external screen is more prone to scratching, though.

Flip – Flip phones, like the Motorola Razr V3, flip open to reveal the screen and keypad. Some, however, have screens on both the inside and the outside of the flip-out cover (such as the Razr2 V9), which offers the best of both worlds. The advantage of flip phones is that they are smaller and thinner than candybars, and are often more comfortable to use. However, keeping the phone small also means there is just a keypad (not a full QWERTY keyboard). In addition, the small battery often means a shorter battery life than larger phones. Flip phones are good picks if you are looking for the smallest, sleekest phone and aren't worried about battery life. However, they are a bad choice if you are looking for extended battery life or want to send a lot of e-mails or text messages.

Slider – Putting the keypad underneath a sliding panel leaves more space for the screen, so phones like the Samsung Blast can have bigger screens than their flip cousins, and often feature larger keypads that make dialing easier. However, the sliding design is more complex than the flip approach, which makes it more likely to break or otherwise malfunction.

Sliding QWERTY – These phones are much the same as normal sliders, but have a full QWERTY keyboard behind their sliding panel. Phones like the Helio Ocean and Verizon EnV offer full QWERTY keyboards that are great for e-mail but make the phones heavier and bulkier.

QWERTY – Many BlackBerry and Palm Treo phones offer a QWERTY keyboard on the outside of the case. This makes the design simpler (there are no sliders for things to get caught in), but also means the keyboard is smaller, which can mean slower typing.

There are lots of phones that don't fit into these broad categories, however. Apple's popular iPhone is a candybar, for instance, but doesn't use a physical keypad; you enter numbers on the touch screen. If you aren't sure which type is right for you, go to a store that has a selection on display and spend some time trying them out. Do a number of common tasks. How quickly, for instance, can you dial a number, look up a contact in the phone book, or send a text message? Then decide which of these features are most important for you, and pick the type that lets you do the most important things the fastest.

Choosing a calling plan
Once you've chosen the network and the phone, it's time to look at the calling plans they offer. The main choice here is how many minutes you want. This is often difficult to work out, but the easiest way to do this is to look at your last three or four bills, if you have a cell phone already. Average the total number of calls you make, or if you are looking to get a family plan with multiple phones, total all the lines and average. Then look for a plan that includes slightly more minutes than this; that way, you will be paying a regular amount every month, but won't have to pay for minutes you don't need. Many plans (such as AT&T's Rollover plans) allow you to carry unused minutes over to the next month, but they usually come with conditions, so make sure you read the fine print.

Each carriers also offers its own unique features that are worth considering. T-Mobile's MyFaves, for example, provides unlimited calls to five selected numbers, and Sprint's free incoming plans don't charge you for incoming calls. Choosing between these can be difficult, but they can save you a lot of money; if you only call a small set of numbers frequently, T-Mobile's MyFaves or Alltell's MyCircle could make your plan a lot cheaper. But make sure the plan you are choosing includes these features; carriers often don't offer these on their cheapest plans, so it might be worth considering a slightly more expensive plan if it ends up saving you money in the long run.

If you are planning on using your phone a lot for e-mailing or Web browsing, you should also look at adding a data feature. Most calling plans don't include data (such as sending e-mail or Web browsing), instead charging you per kilobyte of data you receive. Most carriers allow you to add Web browsing for a small fee (T-Mobile charges $5.99 a month, AT&T charges $9.99 and up), but this often comes with limits. The AT&T $9.99 SmartPhone Connect feature, for instance, allows for 5 MB of data a month (which can quickly get used up) and doesn't include e-mail. If you start using features that aren't covered, or go over your limits, this can get very expensive very quickly. So make sure you know what the limits are.

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Overview
GSM (Global System for Mobile Communications) is the fastest growing and most advanced mobile technology available today. GSM phones work with a small electronic chip called the SIM card. The SIM card holds the phone number assigned by the service provider, your phonebook and other registration information. GSM operates on multiple frequency bands around the world - 900 Mhz and 1800Mhz, used in Europe, Africa, Asia, Australia and South America ; 850 Mhz and 1900 Mhz, used in the.North America and South America. Different service providers operate on different frequency within the country. For example, T-mobile operates on 1900 mhz in the USA, while Cingular operates on 1900 mhz or 850 mhz. When selecting your cell phone make sure that you select a phone that operates on your service provider's band.

Dual band - Usually are phones that operate on 900 mhz or 1800 mhz. These phones will work around the world but, will not work in North America.

Tri-band - Tri-band phones usually include 900 mhz, 1800 mhz and 1900 mhz band. These phones will work around the world and in the North America. These phones will not work with service providers that only support 850 mhz in your area.

Quad band - Quad band phones cover all the bands - 850 mhz, 900 mhz, 1800 mhz, 1900 mhz. Quad band phones will work all over the world with all GSM service providers.

Unlocked GSM Phones
Unlocked GSM phones are not locked to a specific service provider.Unlocked phones will work with any GSM service provider that is supported by the phone's frequency band. Normally, all the phones sold by the service providers are locked to be used with their service only. For example, a locked phone from T-mobile wouldn't work with Cingular's service.

3G
3G is an International Telecommunication Union (ITU) specification for the third-generation mobile communications technology that was created for high-speed transfer of data and multimedia content, such as video, downloads, music and interactive games. 3G aims to increase bandwidth up to 384 Kbps when a device is stationary or moving at pedestrian speed, 128 Kbps in a car, and 2 Mbps in fixed applications. 3G will work over wireless air interfaces, such as GSM, TDMA, and CDMA. The new EDGE service was developed specifically to meet the bandwidth needs of 3G.

EDGE
Enhanced Data GSM Environment (EDGE) is a faster GSM wireless service that can deliver data at rates up to 384 Kbps on a broadband. The standard is based on the GSM standard and uses TDMA.
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Bluetooth
Simply known as a “cable replacement” technology, Bluetooth is a radio-frequency standard that functions as a personal-area network (PAN). It replaces cable-based connections, like USBs, with short-range wireless connections. The technology can be applied between desktops and notebook computers, handhelds, PDAs, mobile phones, camera phones, headphones, printers, digital cameras, headsets, keyboards and computer mice.

GSM Cell Phone Guide

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Cell Phone Buying Guide

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Pick your partner. Before choosing a phone, if you're not already tied into a contract, you will need to select a carrier. Verizon, AT&T, Sprint/Nextel, and T-Mobile are the major nationwide wireless providers. However, you can purchase a plan through smaller companies as well. Service offerings vary from region to region, so know what's available.
Get an upgrade. If already locked into a contract, know when it expires. If you're renewing, you may be eligible for a free phone upgrade or heavy discounts on new models.
Location, location, location. Coverage is usually the most important factor in picking a carrier. After all, there's no point in having a cell phone if you have no reception. If you've ever owned a cell phone, you know how geographically sensitive cell phones can be. Step an inch to the left, and your reception suddenly cuts out. When doing your research, your best bet will be to ask everyone around you how their service ranks.
Look it up. Find out which companies have cell phone towers near you. The more towers, the better reception you're likely to have. CellReception.com lets you type in your zip code to find cell phone towers registered with the FCC. Perhaps even more helpful, however, are people's comments and ratings, which let you track service right down to a street address.
Compare plans. All carriers have several calling plans, usually broken down by minutes used per month. Look at old phone bills to see how many minutes you average and then choose your plan accordingly. Take note of your calling patterns, and when peak and off-peak hours begin and end.
Kids talk free. Tired of paying for your kid's marathon phone conversations? Shop around for family plans — many let you share minutes and text messages.
Everything included. Beware of any additional costs associated with using your cell phone, like receiving and sending text or picture messages, and surfing the Internet. Consider purchasing a data plan that allows for unlimited usage; it may be cheaper than paying for each use.
Try it out. Ask to borrow a friend's cell phone and see how the service is in the places you'd be using it most. Or take advantage of a carrier's return policy; most offer two-week grace periods before you're locked into a contract.
Forgo the extras. Think about what features you really want. Extras like Bluetooth and a built-in camera are great, but they're a waste of money if you're not going to use them.
Choose carefully. Keep in mind which features you will be using most when test-driving different models. If your phone is always in use, consider the model's battery life. If you'll be texting a lot, does it have a comfortable keypad? If you often talk while multitasking, does it have voice-activated dialing and speakerphone? Are there buttons on the outside that will get activated when jostled in your purse?

Tips on buying your mobile

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An increasing number of people of all ages own mobile phones, enjoying the convenience, freedom and re-assurance they provide.

There is a range of different handsets and contracts available, providing mobile communication solutions to suit consumers. The Australian Mobile Telecommunications Association’s Tips on buying your mobile provides a simple step-by-step guide to choosing a mobile phone plan to suit YOUR needs.

As you work through this list, you may find it helpful to write down the features that are important to you.

AMTA also recommends you read Tips on managing your mobile spend, which provides useful tips to help you manage your mobile budget.

Take care if buying second-hand mobiles:
Buying second-hand mobiles online or at auctions can be risky because they may have been reported lost or stolen, or the IMEI may be blocked and consequently the phone will not work . Check the mobile’s status at http://www.lost.amta.org.au/ by entering the mobile’s IMEI number. It only provides details of phones reported lost or stolen at the time of the inquiry. There can be a 72-hour lag between when a mobile is reported lost and stolen to the carrier and showing “blocked” on the website. If you buy a mobile that’s been reported lost or stolen and blocked, the carrier will not unblock it.
What’s your budget? Before you do anything else, think about why you want a mobile phone and determine your budget. There are numerous types of call plan, to suit various budgets and needs. There are also services available to help you keep track of what you spend – consider whether this would help you and check out what options are available. (Look at AMTA’s Tips on managing your mobile spend for more information and hints to help you save money.)

What are your usage patterns? How often will you be using the phone, at what time of day and what will be your average call length? Will you be using the phone mostly for voice calls, or to SMS friends? Your usage patterns may help determine what type of plan is best for you and your budget.

What types of plan are available? There are four basic types of service agreement: fixed-term contracts, monthly plans, pre-paid or leasing. Pre-paid is ideal if you want to ensure you stay within a specified budget - perfect for teenagers. Getting a pre-paid first is also a good way of finding out what your usage is and helping you decide what type of plan might best suit you. Monthly plans allow you the flexibility of receiving monthly bills without signing a long-term contract. Business users may prefer the convenience of fixed-term, while leasing may suit you if you only need a phone and handset for a short time. New ‘capped’ plans (available post or pre-paid, depending on mobile carrier) also offer convenience and value and may suit many users.

What are the call rates within each plan? Call rates vary from plan-to-plan. It's important to assess both the rates and the call charge calculation methods when assessing your options. Issues to consider include: How are call charges calculated? On some plans you will be billed per second, on others, per block of time used (usually per 30 or 60 seconds), or, on the newer ‘capped’ deals (post and pre-paid), ‘call caps’ apply to many services, providing value and certainty; Is there a flag fall (an amount paid for each connection, in addition to call costs)? Are there any special offers (eg cheaper calls off-peak, or to friends on the same network, or for SMS)?

What features do you need in a handset? A basic handset will allow you to make calls and send and receive SMS. You’ll need a more sophisticated one if you want to use the phone abroad, use MMS, voice recording, make video calls, download video or access the internet. Other features to consider are battery capacity (some handsets run longer between charges than others), ease of use, and your coverage requirements (see ‘coverage’). Consider what you really need – or you’ll be paying for features you never use. If you already have a handset, are you eligible for other plans?

How much flexibility do you need? Consider your need for flexibility - and your budget - before you buy a handset or take out a plan. Are you likely to want the flexibility to upgrade your handset when a new one becomes available? Might you want to change to a different plan in six months? There are many different options for paying for handsets (eg up-front, flexi-rent deals, as part of your service agreement), and different plans (whether pre-paid or post-paid) have different terms and conditions – for example some include penalties for changing networks, or plans, for example. Read the small print and check you can meet all the minimum conditions of the contract before signing anything.

What coverage do you require? Where will you be using the phone – only in metropolitan areas, or in the country? The two dominant types of mobile network are GSM and CDMA. A 3G data network has also recently been launched in Australia. Which is best for you depends on where you are likely to require coverage. Check with the carriers where they have coverage to ensure they can provide the service where you need it before signing up. Your coverage requirements may also affect your handset choice (there are CDMA and GSM handsets).

Evaluate the options. Once you’ve worked out what you need/want, do your homework; shop around and compare what is available, and what will best suit your likely usage and budget:

Consider the whole cost of the package. Offers such as ‘$0 upfront’ mean that the cost of the handset is absorbed into the overall contract price, not that the handset is free. Such offers may provide you with a good way of obtaining the handset you want, but they may not be your only – or cheapest – option. Similarly, think about whether you really want any ‘free’ gifts – or whether it’d be cheaper for you to choose a different plan and go and buy the ‘freebie’ yourself. Ensure you understand which services are included at special prices (including ‘caps’). Premium rate services, for example, may not be. Fair use policies may also apply. Make sure you read and understand such policies.

How to Buy a Cell Phone

2012-01-30T04:31:00.001-08:00

Features to Consider

When you're shopping for a phone, you can do some simple hands-on tests in the store to make sure that the handset has everything you need.

Call quality: What good is a phone if it can't make calls? Some of the most simple, bare-bones "feature" phones offer the best call quality--and on the flip side, some fancy smartphones offer dismal calling. When evaluating phones, be sure to make a few test calls. In PCWorld's hands-on tests, we generally make some calls in a quiet room and several calls in a noisy environment. You might not be able to replicate such tests indoors, but try your best. Take note of static, tinny voices, or any interference. Ask the person on the other end of the line if they can hear a disruptive amount of background noise.

Design: Your choices range from phones with large touchscreens to slider-style handsets with full-QWERTY keyboards. Whichever type of phone you select, check its ergonomics. Is it comfortable to hold against your ear, and can you hear callers without constant adjustment? Can you use the phone with one hand? Consider hands-free use: Can you comfortably hold the phone to your ear by scrunching your neck and shoulder? Can it fit comfortably in your pocket or bag? You also want to make sure the phone is durable enough to handle some roughing up. A solidly built phone should be able to withstand getting banged around in a handbag or pocket, as well as a bit of moisture and a short-range drop. You should think about investing in a case or display protector, as well--especially if you’re accident-prone.

Operating system: If you're looking to do more than make calls and send text messages with your phone, consider the platform on which it runs. The mobile operating system you choose will greatly affect the capabilities of your phone. The most popular platforms are Google's Android (found on multiple devices), iOS (found only on iPhone models), BlackBerry OS (found on BlackBerrys of various designs), and Microsoft’s Windows Phone 7. Each has its advantages and disadvantages; you should definitely familiarize yourself with all of the platforms before settling on one.

Display: If you intend do a lot of Web browsing or movie streaming, make sure that the screen is up to snuff. Is it big enough for you to take full advantage of the phone's features? If you're going to surf the Web or edit office documents on your phone, a screen that measures less than 3 inches diagonally will feel cramped.

Consider the screen's resolution: The higher the resolution, the better the screen will look--an important factor if you plan to use your phone to watch videos or view photos.

AMOLED displays perform well in sunlight, but many people think they make colors look oversaturated. qHD displays (whose resolution is one-quarter of a full-HD 1080p frame and three-quarters of a 720p frame) generally look the best in video playback and games.

Cell phone buying guide

2012-01-30T04:29:00.000-08:00

Pick a cell phone service provider
Buying a cell phone is more than a matter of choosing a handset--you also have to pick a service provider, or carrier, as well. Each carrier in the United States offers a different selection of technologies and services, so it's important to think about your needs when making a choice. For that reason, selecting a carrier should be the first step in the cell phone buying process.
Twisting technology

Wireless carriers in the United States operate over two different networks: Code Division Multiple Access (CDMA) and Global System for Mobile Communication (GSM). Though each technology transmits voice and data, they do so in different ways, which makes them incompatible. As a result, you can't take a CDMA phone and use it on GSM or vice versa.

Of the U.S. carriers, AT&T and T-Mobile use GSM while Sprint, Verizon, and smaller carriers such as MetroPCS and U.S. Cellular use CDMA. Though Nextel is part of Sprint, Nextel-branded phones use a third technology called iDEN, or Integrated Digital Enhanced Network. Many of these carriers offer prepaid services. Verizon, for example, has its own prepaid plan page.

CDMA coverage is very strong in the United States, particularly in rural areas, but GSM service has a larger global footprint (it's the standard in Europe, for example) and GSM phones use the convenient SIM cards, which allow you to, among other things, switch phones more easily. Also, when taken on a global scale, GSM users will find a wider selection of handsets. Note: SIM cards now come in a smaller Micro-SIM form factor to accommodate thinner handsets. Not all phones support both sizes, so be sure to check and see what size cards the phone uses before swapping handsets.

With that in mind, if you travel overseas frequently or you enjoy switching out your phone often for the newest model available, then GSM is the better choice. Not all GSM phones will work overseas, however, so be sure to read CNET's quick guide to world phones. But if you'll be making calls mostly in the United States, then CDMA is an equally good option. What's more, some CDMA phones now also support GSM networks for international use.

The Nokia Lumia 800 uses GSM.
Besides technology, there are other factors that should play in your carrier decision. You should begin by deciding which carrier has the most economical service plans and the most attractive selection of phones. The quality of customer service is another determinant, but that can be difficult to evaluate beforehand. Since knowing the pros and cons of each operator isn't easy, we invite you to take a closer look at service providers in our quick guide to cell phone carriers. Besides the major operators, you might also consider Mobile Virtual Network Operator (MVNO) carriers that cater to a special demographic or lifestyle. For example, Virgin Mobile is targeted toward younger users while Boost Mobile is centered on urban users who want advanced features. MVNOs do not operate their own cellular network, but they lease network space from national carriers instead.

8 Tips On BUYING The Mobile Phone That's Right For You!

2012-01-30T04:21:00.001-08:00

Mobile phone technology and mobile services are developing and improving very quickly. If you are confused about what to look for when buying a new phone here are eight important tips to consider.
What Functions Do You Want, and What Functions Do You need?

The most basic function of any mobile phone is to send and receive phone calls and SMS text messages. Beyond the basics some mobile phones have calculators. Others have voice answering and voice dialing, allowing you to send and receive phone calls without using your hands. More sophisticated phones have built in digital cameras, MP3 and video players, computer games and other features.

Choose the phone with the features that you can really use and don’t waste money on a phone with functions that you will seldom use or with functions that duplicate your other electronic gadgets.

Do a Sound and Display Check

Will you be making calls in noisy settings? If so then you should check the volume of the phone and see if it is strong enough to be heard. Make sure that the phone has an easy to use volume control so that you can turn it up whenever necessary and make sure that the volume is really adequate for your needs.
Take a look at the display and also consider the colors. The display is one of the most important features of any mobile phone. Make sure that the display is easily readable even in difficult lighting conditions. You can’t check this feature over the Internet, rather, you should go to the store and examine the phone physically.
If you are buying a phone with a colour display then you should realize that quality of colour and resolution varies dramatically from model to model. If you want to watch videos or look at photos taken with your phone’s camera then you will need a handset with at least “65,000 colour”. The quality of the colours is shown with a number; the higher the number the higher the picture quality.

Check the Quality of the Ring Tones

Polyphonic ring tones are featured in all of the new mobile phones. Polyphonic tones make it possible for a ring tone to sound like many instruments playing together. As with colors, the quality of the ring tone is measured numerically.

If your retailer says that the phone has “16 polyphonic” it means that 16 instruments can be heard in a ring tone. If you want a good sound then you need at least a 16.

See Which Accessories are Included with the Phone

All mobile phones normally come with a battery and charger, but there are other accessories that may be useful to you. Check to see if the phone comes with a spare battery, an earphone, a leather casing, a neck strap or an antenna. If you need any of these accessories and if they are optional, then your phone will cost you more than you thought. If the accessories are part of the deal, then you may be getting a bargain. Also, if you don’t need an accessory now, but would like to get one in the future, check to see if accessories for your model are easily available on the market.

Find Out How Long the Battery Will Last

Battery life is an important variable. The average user only asks about the “talk time” of a a battery. However, “stand-by” time is just as important, especially for people who do not want to carry around a charger with them.

It is common to find phones whose batteries have a three to seven-hour talk time, but you should also find out whether the battery has enough stand-by time so that you can make it through the entire day without recharging.

Consider the “Look and Feel” of the Phone

Once again you can’t choose a phone from a catalog or over the Internet. You might prefer to go down to the store and handle the phone before buying it. Feel how much it weighs and see if the menus are easy to understand. Take a look at the layout of the keyboard and other buttons. On some of the smaller phones the buttons are so small that it is difficult and tiresome to dial a number or compose a message.

If you consider your phone a fashion accessory then choose one that best suits your personality and style.

Take a Careful Look at the Price

Be sensible. Buy a mobile phone that lets you stay within your budget. If you follow the previous tips and get a phone that matches your requirements, you should be able to get a handset that will not put you in debt or force you to cut back on your usual expenditures. Remember one thing about consumer electronics: the prices usually fall. If you can’t afford to buy a phone that can show videos this year, next year it may be within your reach.

online free information

How to Buy a Laptop

Evaluate Mobile Phone Features

Do you plan to use your mobile phone outside of your local area?

Would you like access to the internet or email from your mobile phone?

Additional Features

How important is your phone's size and weight?

Select a Mobile Phone Service Provider

Australian Service Providers

Pre-Paid Services

Coverage

Buy with Confidence

Know your seller

Legal Disclaimer

Cell Phone Buying Guide 2010

Choosing a carrier

The difference between a smartphone and a feature phone

Different form factors

How to Buy a Cell Phone

Tips for buying and giving a mobile device

Cell Phone Buying Guide

What You Need to Know:

HOW TO CHOOSE THE RIGHT CELL PHONE

Choose a plan

Choose a technology

Cell Phone Buying Guide

GSM Cell Phone Guide

Cell Phone Buying Guide

Tips on buying your mobile

How to Buy a Cell Phone

Cell phone buying guide

8 Tips On BUYING The Mobile Phone That's Right For You!