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<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_d0e157678_href.jpg" scale="150" placement="inline">
</image>
</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" scope="external">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>