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  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="GUID-667C0481-2DEF-4618-9AA5-8DF528082061" xml:lang="en"><title>Accessory
Services Overview</title><shortdesc>Accessory Services abstract accessory-related services for platform
and SDK clients and provides accessory-related APIs for adaptation (audio
and display) and accessory plug-ins.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
<section id="GUID-6C29F2CD-6FBE-4805-957A-CB08163DFC00"><title>Purpose</title><p>Accessory Services is a group of components
that support APIs for platform clients to retrieve accessory connection status
information, and device and services type information. It also provides adaptation
APIs for the addition of new Accessory Services plug-in components. </p></section>
<section id="GUID-9236506F-077D-4AB1-AE4C-9CE391F42F98"><title>Architecture</title><p>The architecture of Accessory Services
revolves around the Accessory and the Remote Control Framework. Accessory
Framework provides platform clients with access to the accessory functionality
on the device, while abstracting away accessory, hardware, bearer and protocol-specific
details from the software layers. Accessory Framework also provides accessory
policy and adaptation APIs for the addition of new Accessory Framework plug-in
components (if required). The Remote Control Framework provides APIs required
to send and receive remote control commands to/from an accessory connected
to a phone.</p><p>The core of the Accessory Framework is the Accessory Server.
Accessory Server has a central role in accessory-related connection/disconnection
handling on the Symbian platform. The Accessory Framework depends on the concepts,
such as Generic ID, Accessory Policy, Accessory Handlers and Accessory Mode.
These concepts are described in the following section.</p><p>Remote Control
Framework exposes the Remote Control Server using the Remote Control Core
APIs. The remote control commands are understood by the Key Event Converter
and passed on to the Target Selector Plug-in (TSP) Controller by the Remote
Control Framework. Then TSP decides which application must handle this request
and passes that information to the Remote Control Server. Finally, the request
is handled by that application. For more information about Remote Control
concepts, see the <b>Remote Control Framework</b> section.</p><p>The following
figure illustrates the architecture of Accessory Services:</p><fig id="GUID-EF39A7CD-BA15-4F2D-96C6-C54672226E98">
<title>Accessory Services Architecture</title>
<image href="GUID-5AE741A2-68C5-4219-8F2A-ECE0A819FCAA_d0e158427_href.jpg" scale="150" placement="inline"/>
</fig></section>
<section id="GUID-7AB78BEA-315A-4CC0-B5B6-A7A28568F2B2"><title>Description</title><p>This section describes the key concepts
associated with Accessory Services.</p><ul>
<li><p><b>Generic ID</b>: Generic ID provides the means to describe, detect,
connect, and control an enhancement without a need to use hardware or provider-specific
definitions. Thus Generic ID must be a native concept for any accessory-related
platform software. For the platform purposes, Generic ID must be defined so
that it covers all the enhancement device types, bearers, protocols, and accessory
feature profiles that the platform supports and for which information is needed.</p> </li>
<li><p><b>Accessory Policy:</b> Accessory Policy provides the Generic ID data
type for identifying an accessory on the basis of its features, instead of
an accessory-specific ID. Accessory Server uses Accessory Policy through the
Accessory Policy API to get information about the connected accessories. A
connected accessory is identified using an assigned Generic ID, which is a
data structure that describes the relevant physical and logical features of
the accessory.</p> </li>
<li><p><b>Accessory Mode:</b> Accessory Mode describes the accessory connection
status of the devices connected to a phone and indicates whether the audio
is routed into the accessory or not. Accessory Mode typically affects the
vibra state, lights state, texts, some UI icons and menu items. </p><p><b>Note:</b> Accessory
Mode is a single-valued state, unlike the accessory connection status. Some
supported Accessory Modes include hand portable, wired headset, wireless headset,
wired car kit, wireless car kit, headphones, text device, music stand and
TV-out.</p> </li>
<li><p><b>Accessory Handlers:</b> Accessory Handlers (ASYs) form the Accessory
Framework adaptation layer. Accessory Server hosts multiple ASYs. For example,
wired ASY, bluetooth ASY, plugged display ASY and so on. ASYs can be understood
as an accessory adaptation layer between the Accessory Framework and any other
Symbian platform or hardware-related software on the phone. Typical
task of an ASY is accessory detection (registering for hardware indications)
and providing the capabilities of the accessories to the Accessory framework.</p> </li>
<li><p><b>Controller:</b> Controller is a device that sends a control message
or command to a target device and is ready to capture responses.</p> </li>
<li><p><b>Target:</b> Target is a device that accepts the control message
or command from the controller, invokes necessary procedures and sends out
responses to controller. </p> </li>
<li><p><b>Bearer:</b> The bearer is a carrier that acts like a vehicle of
transmission for remote control messages. The bearer here is an ECom plug-in
to the Remote Control Server.</p> </li>
</ul><p/></section>
<section id="GUID-93D60E05-F086-46F4-A0A6-2B8227BBABED"><title>Components</title><p>Accessory Services consists of the following
components: </p><ul>
<li><p><b>Accessory Monitor:</b> Provides APIs to retrieve information about
the connected accessories, such as a headset and car kit. </p></li>
<li><p><b>Accessory Remote Control:</b> Provides APIs for clients to communicate
with remote targets in a terminal and remote targets outside a terminal.</p> </li>
<li><p><b>Accessory Server:</b> This is a core component that exposes accessory-related
client and adaptation APIs through the Accessory Framework. The Accessory
Framework provides APIs to query accessory-related information, adjust accessory-related
user settings and to request control for accessory-related functions. </p> </li>
<li><p><b>Headset Status API:</b> Provides APIs for checking the headset status.
For example, headset status change notifications.</p> </li>
<li><p><b>Target Selector Plug-in (TSP) Client Mapper:</b> Provides APIs to
create mappings between remote control clients.</p> </li>
<li><p><b>Plugged Display:</b> Plugged Display component is an ASY that enables
High-Definition Multimedia Interface (HDMI) and TV-out support. For more information
about HDMI, see <xref href="http://en.wikipedia.org/wiki/HDMI.dita">Wikipedia</xref>.</p> </li>
<li><p><b>Remote Control Framework:</b> Provides APIs needed to send and receive
remote control commands to/from a Bluetooth enabled device.</p> </li>
</ul></section>
<section id="GUID-18563CE6-A880-48E4-96BA-3B50CA8A373F"><title>Using Accessory Services</title><p>You can use features provided
by Accessory Services to perform the following tasks:</p><ul>
<li><p>Retrieve accessory mode, connection status, accessory device and service
type information.</p></li>
<li><p>Retrieve accessory control and connection-related functionality.</p></li>
<li><p>Request for a protocol-specific connection handle for accessory audio
control.</p></li>
<li><p>Handle accessory-related key events.</p></li>
<li><p>Monitor accessories connected to a phone.</p></li>
<li><p>Identify accessories connected based on its features, using Generic
IDs.</p></li>
<li><p>Configure accessory-related settings.</p></li>
<li><p> Retrieve headset connection status.</p></li>
<li><p>Create mappings between remote control clients.</p></li>
<li><p>Configure TV-out settings.</p></li>
</ul></section>
</conbody></concept>