Like iPhone and iPod Touch, the iPad is controlled by a multitouch display—a departure from most previous tablet computers, which used a pressure-triggered stylus—as well as a virtual onscreen keyboard in lieu of a physical keyboard. The iPad uses a wireless local area network ("Wi-Fi") connection to access local area networks and the Internet. Some models also have a 3G wireless network interface which can connect to HSPAor EV-DO data networks and on to the Internet. The device is managed and synced by iTunes running on a personal computer via USB cable.

Apple released the first iPad in April 2010, and sold 3 million of the devices in 80 days. During 2010, Apple sold 14.8 million iPads worldwide, representing 75 percent of tablet PC sales at the end of 2010.

By the release of the iPad 2 in March 2011, more than 15 million iPads had been sold[19] – selling more than all other tablet PCs combined since the iPad's release. In 2011, it is expected to take 83 percent of the tablet computing market share in the United States.

Apple's first tablet computer was the Newton MessagePad 100, introduced in 1993, which led to the creation of the ARM6 processor core withAcorn Computers. Apple also developed a prototype PowerBook Duo-based tablet, the PenLite, but decided not to sell it in order to avoid hurting MessagePad sales. Apple released several more Newton-based PDAs; the final one, the MessagePad 2100, was discontinued in 1998.

Apple re-entered the mobile-computing markets in 2007 with the iPhone. Smaller than the iPad but featuring a camera and mobile phone, it pioneered the multitouch finger-sensitive touchscreen interface of Apple's iOS mobile operating system. By late 2009, the iPad's release had been rumored for several years. Such speculation mostly talked about "Apple's tablet"; specific names included iTablet and iSlate. The actual name is reportedly an homage to the Star Trek PADD, a fictional device very similar in appearance to the iPad. The iPad was announced on January 27, 2010, by Steve Jobs at an Apple press conference at the Yerba Buena Center for the Arts in San Francisco.

Jobs later said that Apple began developing the iPad before the iPhone, but temporarily shelved the effort upon realizing that its ideas would work just as well in a mobile phone. The iPad's internal codename was K48, which was revealed in the court case surrounding leaking of iPad information before launch. 

Apple began taking pre-orders for the iPad from U.S. customers on March 12, 2010. The only major change to the device between its announcement and being available to pre-order was the change of the behavior of the side switch from sound muting to that of a screen rotation lock. The Wi-Fi version of the iPad went on sale in the United States on April 3, 2010. The Wi-Fi + 3G version was released on April 30. 3G service in the United States is provided by AT&T and was initially sold with two prepaid contract-free data plan options: one for unlimited data and the other for 250 MB per month at half the price. On June 2, 2010, AT&T announced that effective June 7 the unlimited plan would be replaced for new customers with a 2 GB plan at slightly lower cost; existing customers would have the option to keep the unlimited plan. The plans are activated on the iPad itself and can be canceled at any time.

The iPad was initially only available online at The Apple Store as well as the company's retail locations. The iPad has since been available for purchase through many retailers including Amazon, Wal-Mart, Best Buy, Verizon, and AT&T. The iPad was launched in Australia, Canada, France, Germany, Italy, Japan, Spain, Switzerland and the United Kingdom on May 28. Online pre-orders in those countries began on May 10. Apple released the iPad in Austria, Belgium, Hong Kong, Ireland, Luxembourg, Mexico, The Netherlands, New Zealand and Singapore on July 23, 2010. Israel briefly prohibited importation of the iPad because of concerns that its Wi-Fi might interfere with other devices. On September 17, 2010, the iPad officially launched in China.

The device was initially popular with 300,000 iPads being sold on their first day of availability. By May 3, 2010, Apple had sold a million iPads, this was in half the time it took Apple to sell the same number of original iPhones. During the October 18, 2010, Financial Conference Call, Steve Jobs announced that Apple had sold more iPads than Macs for the Fiscal Quarter. In total, Apple sold more than 15 million first generation iPads prior to the launch of the iPad 2. 

Apple Inc. CEO Steve Jobs unveiled the iPad 2, the second generation of the device, at a March 2, 2011, press conference, despite being on medical leave at the time. About 33% thinner than its predecessor, the iPad 2 has a better processor, a dual core Apple A5 that Apple says is twice as fast as its predecessor for CPU operations and up to nine times as fast for GPU operations. It includes front and back cameras that support theFaceTime video calling application, as well as a three-axis gyroscope. It retains the original's 10-hour battery life and has a similar pricing scheme.

The iPad 2 has been available for purchase, depending on stock availability, since March 11, 2011, at Apple retail stores in the United States, as well as to United States customers shopping online at Apple's retail website. The iPad 2 was released internationally in 25 other countries on March 25, 2011, including Australia, Canada, France, Germany, Mexico and the United Kingdom, but not Japan as originally scheduled due to theearthquake and tsunami. 

The iPad's touchscreen display is a 1024 × 768 pixel, 19.7×14.8 cm liquid crystal display (diagonal 9.7 in (24.6 cm)), with fingerprint- and scratch-resistant glass. Steve Jobs backed the choice of screen size, saying a 7-inch screen would be "too small to express the software" and that 10 inches was the minimum for a tablet screen. Like the iPhone, the iPad is designed to be controlled by bare fingers; normal, non-conductive gloves andstyli do not work, although there are special gloves and capacitive styli designed for this use.

The display responds to other sensors: an ambient light sensor to adjust screen brightness and a 3-axis accelerometer to sense iPad orientation and switch between portrait and landscape modes. Unlike the iPhone and iPod Touch's built-in applications, which work in three orientations (portrait, landscape-left and landscape-right), the iPad's built-in applications support screen rotation in all four orientations, including upside-down. Consequently, the device has no intrinsic "native" orientation; only the relative position of the home button changes.

There are four physical switches on the iPad, including a home button near the display that returns the user to the main menu, and three plastic physical switches on the sides: wake/sleep and volume up/down, plus a software-controlled switch whose function has changed with software updates. Originally the switch locked the screen to its current orientation, but the iOS 4.2 changed it to a mute switch, with rotation lock now available in an onscreen menu. In the iOS 4.3 update, released with the iPad 2, a setting was added to allow the user to specify whether the side switch was used for rotation lock or mute.

The original iPad had no camera; the iPad 2 has a front VGA camera and a rear-facing 720p camera, both capable of still images and 30fps video. The rear-facing camera has a 5x digital zoom for still images only. Both shoot photo and video in a 4:3 fullscreen aspect ratio, unlike the iPhone 4, which shoots in a 16:9 widescreen aspect ratio. Unlike the iPhone, the iPad does not support tap to focus. The cameras allow FaceTime video messaging with iPhone 4, iPod Touch 4, and Snow Leopard/Lion Macs.

The iPad can use Wi-Fi network trilateration from Skyhook Wireless to provide location information to applications such as Google Maps. The 3G model supports A-GPS to allow its position to be calculated with GPS or relative to nearby cellphone towers; it also has a black strip on the back to aid 3G reception.

The iPad has a headphone jack and a proprietary Apple dock connector, but no Ethernet or USB port.

The iPad has two internal mono speakers located on the bottom-right of the unit. In the original iPad, the speakers push sound through two small sealed channels leading to the three audio ports carved into the device, while the iPad 2 has its speakers behind a single grill.

A volume switch is on the right side of the unit. A 3.5-mm TRRS connector audio-out jack on the top-left corner of the device provides stereo sound for headphones with or without microphones and/or volume controls. The iPad also contains a microphone that can be used for voice recording.

The built-in Bluetooth 2.1 + EDR interface allows wireless headphones and keyboards to be used with the iPad. However, the iOS does not currently support file transfer via Bluetooth. iPad also features 1024 x 768 VGA video output for limited applications, screen capture, connecting an external display or television through an accessory adapter.

The iPad uses an internal rechargeable lithium-ion polymer (LiPo) battery. The batteries are made in Taiwan by Simplo Technology (60%) and Dynapack International Technology. The iPad is designed to be charged with a high current of 2 amperes using the included 10 W USB power adapter. While it can be charged by a standard USB port from a computer, these are limited to 500 milliamperes (0.5 amps). As a result, if the iPad is running while powered by a normal USB computer port, it may charge very slowly, or not at all. High-power USB ports found in newer Apple computers and accessories provide full charging capabilities.

Apple claims that the battery for both generations of iPad can provide up to 10 hours of video, 140 hours of audio playback, or one month on standby. Like any rechargeable battery technology, the iPad's battery loses capacity over time, but is not designed to be user-replaceable. In a program similar to the battery-replacement program for the iPod and the original iPhone, Apple will replace an iPad that does not hold an electrical charge with a refurbished iPad for a fee of US$99 plus $6.95 shipping. As a different unit is supplied, user data are not preserved. The refurbished unit will have a new case. The warranty on the refurbished unit may vary between jurisdictions.

Independent companies also provide a battery replacement service, returning the original unit with new battery but original case. Alternatively it is possible for a technically competent user to buy and install a new battery, which may invalidate any remaining warranty on the iPad. The task does not require soldering, but is technically challenging. 

The iPad was released with three capacity options for storage: 16, 32, or 64 GB of internal flash memory. All data is stored on the internal flash memory, with no option to expand storage. Apple sells a "camera connection kit" with an SD card reader, but it can only be used to transfer photos and videos.

The side of the Wi-Fi + 3G model has a micro-SIM slot (not mini-SIM). The 3G iPad can be used with any compatible GSM carrier, unlike the iPhone, which is usually sold 'locked' to specific carriers. Japan is the exception to this, where the iPad 3G is locked to Softbank. In the U.S., data network access via T-Mobile's network is limited to slower EDGE cellular speeds because T-Mobile's 3G Network uses different frequencies. The iPad 2 introduced a third tier of models with CDMA support for Verizon Wireless in the United States, available separately from the AT&T capable version.

Apple offers several iPad accessories, most of which are adapters for the proprietary 30-pin dock connector, the iPad's only port besides the headphone jack. A dock holds the iPad upright at an angle, and has a dock connector and audio line out port. Each generation of iPad requires a corresponding dock. A dock that included a physical keyboard is available only for the original iPad, but both generations are compatible with Bluetooth keyboards that also work with Macs and PCs. The iPad can be charged by a standalone power adapter ("wall charger") also used for iPods and iPhones, and a 10 W charger is included with the iPad.

Apple sells a camera connection kit that consists of two separate adapters for the dock connector, one to USB Type A, the other an SD card reader, meant to transfer photos and videos. A third party sells an adapter that includes USB, SD, and microSD on a single unit. An adapter to VGA connectors allows the iPad to work with external monitors and projectors. Another adapter mirrors the screen onto HDMI compatible devices in 1080p and works with all apps and rotations. Unlike other adapters, it allows the iPad to charge through another dock connector. While the HDMI adapter was released with and advertised for the iPad 2, it also works with the first generation iPad, the iPhone 4, and the fourth generation iPod Touch. 

Smart Covers are screen protectors that magnetically attach and align to the face of the iPad 2. The cover has three folds which allow it to convert into a stand, which is also held together by magnets.[83] While original iPad owners could purchase a black case that included a similarly folding cover, the Smart Cover is meant to be more minimal, easily detachable, and protects only the screen. Smart Covers have a microfiber bottom that cleans the front of the iPad, which wakes up when the cover is removed. There are five different colors of both polyurethane and leather, with leather being more expensive. Smart Covers are not compatible with the original iPad.

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