iPhone 5

The display responds to three sensors (four on the iPhone 4). A proximity sensor deactivates the display and touchscreen when the device is brought near the face during a call. This is done to save battery power and to prevent inadvertent inputs from the user's face and ears. An ambient light sensor adjusts the display brightness which in turn saves battery power. A 3-axis accelerometer senses the orientation of the phone and changes the screen accordingly, allowing the user to easily switch between portrait and landscape mode.Photo browsing, web browsing, and music playing support both upright and left or right widescreen orientations.Unlike the iPad, the iPhone does not rotate the screen when turned upside-down, with the Home button above the screen, unless the running program has been specifically designed to do so. The 3.0 update added landscape support for still other applications, such as email, and introduced shaking the unit as a form of input.The accelerometer can also be used to control third-party apps, notably games. The iPhone 4 also includes a gyroscopic sensor, enhancing its perception of how it is moved.

A software update in January 2008allowed the first-generation iPhone to use cell tower and Wi-Fi network locations trilateration,despite lacking GPS hardware. The iPhone 3G, 3GS and 4 employ A-GPS, and the iPhone 3GS and 4 also have a digital compass.

Audio and output

One of two speakers (left) and the microphone (right) surround the dock connector on the base of the original iPhone. If a headset is plugged in, sound is played through it instead.

The bottom of the iPhone sports a speaker (left) and a microphone (right) flanking the dock connector. One loudspeaker is located above the screen as an earpiece, and another is located on the left side of the bottom of the unit, opposite a microphone on the bottom-right. The iPhone 4 includes an additional microphone at the top of the unit for noise cancellation, and switches the placement of the microphone and speaker on the base on the unit—the speaker is on the left.Volume controls are located on the left side of all iPhone models and as a slider in the iPod application.

iPhone 4

Screen and input

The touchscreen is a 9 cm (3.5 in) liquid crystal display with scratch-resistant glass.The capacitive touchscreen is designed for a bare finger, or multiple fingers for multi-touch sensing. The screens on the first three generations have a resolution of 320 x 480 (HVGA) at 163 ppi, while that of iPhone 4 has a resolution of 640 x 960 at 326 ppi.

The touch and gesture features of the iPhone are based on technology originally developed by FingerWorks.Most gloves and styluses prevent the necessary electrical conductivity; however, capacitive styli can be used with iPhone's finger-touch screen. The iPhone 3GS and later also feature a fingerprint-resistant oleophobic coating.

The iPhone has a minimal hardware user interface, featuring only four or five buttons, depending on the generation. The only physical menu button is situated directly below the display, and is called the "Home button" because it closes the active app and navigates to the home screen of the interface. The home button is denoted not by a house, as on many other similar devices, but a rounded square, reminiscent of the shape of icons on the home screen. A multifunction sleep/wake button is located on the top of the device. It serves as the unit's power button, and also controls phone calls. When a call is received, pressing the sleep/wake button once silences the ringtone, and when pressed twice transfers the call to voicemail. Situated on the left spine are the volume adjustment controls. The iPhone 4 has two separate circular buttons to increase and decrease the volume; all earlier models house two switches under a single plastic panel, known as a rocker switch, which could reasonably be counted as either one or two buttons. Directly above the volume controls is a silence switch that mutes all sound when engaged. All buttons except Home were made of plastic on the original iPhone and metal on all later models. The touchscreen furnishes the remainder of the user interface.

iPhone 3

Apple sold 6.1 million original iPhone units over five quarters.Recorded sales have been growing steadily thereafter, and by the end of fiscal year 2010, a total of 73.5 million iPhones were sold.By 2010/2011, the iPhone has a market share of barely 4% of all cellphones, but Apple still pulls in more than 50% of the total profit that global cellphone sales generate.Sales in Q4 2008 surpassed temporarily those of RIM's BlackBerry sales of 5.2 million units, which made Apple briefly the third largest mobile phone manufacturer by revenue, after Nokia and Samsung.Approximately 6.4 million iPhones are active in the U.S. alone.While iPhone sales constitute a significant portion of Apple's revenue, some of this income is deferred.

The back of the original iPhone was made of aluminum with a black plastic accent. The iPhone 3G and 3GS feature a full plastic back to increase the strength of the GSM signal.The iPhone 3G was available in an 8 GB black model, or a black or white option for the 16 GB model. They both are now discontinued. The iPhone 3GS was available in both colors, regardless of storage capacity. The white model was discontinued in favor of a black 8 GB low-end model. The iPhone 4 has an aluminosilicate glass front and back with a stainless steel edge that serves as the antennae. It is available in black; a white version was announced, but has as of March 2011not been released.

The iPhone has garnered positive reviews from critics like David Pogue and Walter Mossberg.The iPhone attracts users of all ages,and, besides consumer use, the iPhone has also been adopted for business purposes.

On January 11, 2011, Verizon announced during a media event that it had reached an agreement with Apple and would begin selling a CDMA2000 iPhone 4. Verizon said it would be available for pre-order on February 3, with a release set for February 10. In Feb 2011, the Verizon iPhone accounted for 4.5 percent of all iPhone ad impressions in the U.S. on Millennial Media’s mobile ad network.

On March 2, 2011, at the iPad 2 event, Apple announced that they have sold 100 million iPhones.

iPhone 2

History and availability

Development of the iPhone began in 2005 with Apple CEO Steve Jobs' direction that Apple engineers investigate touchscreens.He also steered the original focus away from a tablet, like the iPad, and towards a phone.Apple created the device during a secretive and unprecedented collaboration with AT&T Mobility—Cingular Wireless at the time—at an estimated development cost of US$150 million over thirty months.Apple rejected the "design by committee" approach that had yielded the Motorola ROKR E1, a largely unsuccessful collaboration with Motorola. Instead, Cingular gave Apple the liberty to develop the iPhone's hardware and software in-house in exchange for exclusive U.S. sales until 2011.

Jobs unveiled the iPhone to the public on January 9, 2007 at Macworld 2007. Apple was required to file for operating permits with the FCC, but since such filings are made available to the public, the announcement came months before the iPhone had received approval. The iPhone went on sale in the United States on June 29, 2007, at 6:00 pm local time, while hundreds of customers lined up outside the stores nationwide.The original iPhone was made available in the UK, France, and Germany in November 2007, and Ireland and Austria in the spring of 2008.

On July 11, 2008, Apple released the iPhone 3G in twenty-two countries, including the original six.Apple released the iPhone 3G in upwards of eighty countries and territories.Apple announced the iPhone 3GS on June 8, 2009, along with plans to release it later in June, July, and August, starting with the U.S., Canada and major European countries on June 19. Many would-be users objected to the iPhone's cost,and 40% of users have household incomes over US$100,000.In an attempt to gain a wider market, Apple retained the 8 GB iPhone 3G at a lower price point. When Apple introduced the iPhone 4, the 3GS became the less expensive model. Apple reduced the price several times since the iPhone's release in 2007, at which time an 8 GB iPhone sold for $599. An iPhone 3GS with the same capacity now costs $49. However, these numbers are misleading, since all iPhone units sold through AT&T require a two-year contract (costing several hundred dollars), and a SIM lock.