Screen and input
Connectivity
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.[60]For wired connectivity, the iPad has a proprietary Apple dock connector; it lacks the Ethernet and USB ports of larger computers.[9]
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 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.[61] However, the iOS does not currently support file transfer via Bluetooth.[62] iPad also features 1024 x 768 VGA video output for limited applications,[63] screen capture,[64] connecting an external display or television through an accessory adapter.
Power and battery
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.[65] The iPad is designed to be charged with a high current (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 (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.[66]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 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 $99 (plus $6.95 shipping).[67][68]
Storage and SIM
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.[69]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.[70] Japan is the exception to this, where the iPad 3G is locked to Softbank.[71] 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.[72][73]
