Screen and input

Steve Jobs, Apple CEO, introducing the iPad

The iPad's touchscreen display is a 9.7 in (25 cm) liquid crystal display (1024 × 768 pixels) with fingerprint-resistant 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."[26] He said 10 inches was the minimum for a tablet screen.[26] Like the iPhone, the iPad is designed to be controlled by bare fingers; normal gloves and styli that prevent electrical conductivity may not be used,[27] although there are special gloves and capacitive styli designed for this use.[28][29]

The display responds to two 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 built-in applications, which work in three orientations (portrait, landscape-left and landscape-right), the iPad built-in applications support screen rotation in all four orientations (the three aforementioned ones along with upside-down),[30] meaning that the device has no intrinsic "native" orientation; only the relative position of the home button changes.

In total there are four physical switches on the iPad, including a home button below 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 third which, as of iOS 4.2, acts as a mute switch.[10] Initially this switch was utilized to lock out the screen rotation function (reportedly to prevent unintended rotation when the user is lying down).[31] However, with the iOS 4.2 update, this functionality was removed and rotation lock is now controlled with a software toggle via the iOS task switcher. There is no means to reassign the physical switches functionality in the official iOS release.

Connectivity

The iPad 3G, unlike the Wi-Fi model, has a black plastic piece on the underside which allows cellular signals to pass through it.

The iPad can use Wi-Fi network trilateration from Skyhook Wireless to provide location information to applications such as Google Maps. The 3G model contains A-GPS to allow its position to be calculated with GPS or relative to nearby cellphone towers; it also has a black plastic accent on the back side to improve 3G radio sensitivity.[32]

For wired connectivity, the iPad has a proprietary Apple dock connector; it lacks the Ethernet and USB ports of larger computers.[10]

Audio and output

The iPad has two internal speakers that push mono sound through two small sealed channels to the three audio ports carved into the bottom-right of the unit.[13] A volume switch is on the right side of the unit.

A 3.5-mm TRS 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.[33] However, the iOS does not currently supportfile transfer via Bluetooth.[34] iPad also features 1024 x 768 VGA video output for connecting an external display or television.[35]

Power and battery

iPad in the iPad Keyboard Dock

The iPad uses an internal rechargeable lithium-ion polymer battery (LiPo). The batteries are made in Taiwan by Simplo Technology, which makes 60% of them, and Dynapack International Technology.[36] The iPad is designed to be charged with a high current (2 amperes) using the included USB 10-watt (0.013 hp) power adapter. While it can be charged by a standard USB port from a computer, these are limited to 500 milliamperes (half an amp). As a result, if the iPad is turned on while connected to a normal USB computer port, it may charge much more slowly, or not at all. High-power USB ports found in newer Apple computers and accessories provide full charging capabilities.[37]

Apple claims that the iPad's battery can provide up to 10 hours of video, 140 hours of audio playback, or one month on standby. Like any battery technology, the iPad's LiPo battery loses capacity over time, but is not designed to be user-replaceable. In a program similar to the battery-replacement program for theiPod and the original iPhone, Apple will replace an iPad that does not hold an electrical charge with a refurbished iPad for a fee of $99 (plus $6.95 shipping).[38][39]

Storage and SIM

The iPad was released with three options for internal storage size: a 16, 32, or 64 GB flash drive. All data is stored on the flash drive and there is 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.[40]

The side of the Wi-Fi + 3G model has a micro-SIM slot (not mini-SIM). Unlike the iPhone, which is usually sold locked to specific carriers, the 3G iPad is sold unlocked and can be used with any compatible GSM carrier.[41] Japan is the exception to this, where the iPad 3G is locked to Softbank.[42] 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.[43][44]

Optional accessories

The iPad in its case

Apple offers several iPad accessories, including:[10]

  • iPad Keyboard Dock with hardware keyboard, 30-pin connector, and audio jack
  • iPad Case which can be used to stand the iPad in various positions
  • iPad Dock with 30-pin connector and audio jack
  • iPad Dock Connector to VGA Adapter for external monitor or projector
  • iPad Camera Connection Kit including a USB Type A connector adapter and an SD card reader, for transferring photos and videos
  • iPad 10W USB Power Adapter with 2 A output (10 W)