| page.title=Android Open Accessory Protocol |
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| <p> Android Open Accessory support allows external USB hardware (an Android USB accessory) to interact |
| with an Android-powered device in a special accessory mode. When an Android-powered powered device |
| is in accessory mode, the connected accessory acts as the USB host (powers the bus and enumerates |
| devices) and the Android-powered device acts in the USB accessory role. Android USB accessories are |
| specifically designed to attach to Android-powered devices and adhere to the Android Open Accessory |
| Protocol, that allows them to detect Android-powered devices that support |
| accessory mode. Accessories must also provide 500mA at 5V for charging power. Many previously |
| released Android-powered devices are only capable of acting as a USB device and cannot initiate |
| connections with external USB devices. Android Open Accessory support overcomes this limitation |
| and allows you to build accessories that can interact with an assortment of Android-powered |
| devices by allowing the accessory to initiate the connection.</p> |
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| <p><strong>Note:</strong> Accessory mode is ultimately dependent on the device's hardware and not all devices |
| support accessory mode. Devices that support accessory mode can be filtered using a <code><uses-feature></code> |
| element in your corresponding application's Android manifest. For more information, see the |
| <a href="http://developer.android.com/guide/topics/connectivity/usb/accessory.html#manifest">USB Accessory</a> |
| developer guide.</p> |
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| <p>Android Open Accessory support is included in Android 3.1 (API Level 12) and higher, and supported |
| through an <a href="https://developers.google.com/android/add-ons/google-apis/">Add-On Library</a> in Android |
| 2.3.4 (API Level 10) and higher.</p> |
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