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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><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><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 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_d0e133491_href.jpg" scale="150" placement="inline"/>

</fig></section>

<section><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><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><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>