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<task id="GUID-B467D117-6670-5614-9886-539CF654F9D8" xml:lang="en"><title>Call

Sub-session Tutorial</title><prolog><metadata><keywords/></metadata></prolog><taskbody>

<context><p>Lines can have zero or more active calls. The call functionality

includes dialling a number, to waiting for incoming calls, and to hanging

up. A client can get status and capabilities information, and can be notified

of changes. </p><p>The call interface is provided by the <codeph>RCall</codeph> class. </p><p>This

section describes the Call sub-session functions and how to use them.</p><table id="GUID-A02C8979-43F9-4BB8-ACD3-A2E7BFD342BD">

<tgroup cols="2"><colspec colname="col1"/><colspec colname="col2"/>

<tbody>

<row>

<entry><b>Function</b></entry>

<entry><b>Description</b></entry>

</row>

<row>

<entry><codeph>Open()</codeph></entry>

<entry>Call this function to open a line sub-session in a phone. Similarly

a line sub-session can be created in a server. The server is used when the

phone functionality for a line is not required. </entry>

</row>

<row>

<entry><codeph>GetCaps()</codeph></entry>

<entry>Call this function to get the line capabilities. </entry>

</row>

<row>

<entry><codeph>NotifyCapsChange()</codeph></entry>

<entry>Call this function to receive notification there are changes in a line.

To cancel a request, call the <codeph>NotifyCapsChangesCancel()</codeph> function. </entry>

</row>

<row>

<entry><codeph>GetStatus()</codeph></entry>

<entry>Call this function to get the line status. </entry>

</row>

<row>

<entry><codeph>GetHookStatus()</codeph></entry>

<entry>Call this function to get the status of a hook associated with the

line. </entry>

</row>

<row>

<entry><codeph>EnumerateCall()</codeph></entry>

<entry>Call this function to get the number of calls opened in a line. </entry>

</row>

<row>

<entry><codeph>GetCallInfo() </codeph></entry>

<entry>Call this function to get a detailed information about a call in a

line sub-session. </entry>

</row>

<row>

<entry><codeph>GetInfo() </codeph></entry>

<entry>Call this function to get the information about the current line. </entry>

</row>

<row>

<entry><codeph>NotifyIncomingCall() </codeph></entry>

<entry>Call this function to get notification of incoming calls. To cancel

an earlier request for the incoming call notification, call the <codeph>NotifyIncomingCallCancel()</codeph>. </entry>

</row>

<row>

<entry><codeph>NotifyHookChange() </codeph></entry>

<entry>Call this function to get the notification of hook status changes. </entry>

</row>

<row>

<entry><codeph>NotifyStatusChange() </codeph></entry>

<entry>Call this function to get the notification about the status changes

of a line. </entry>

</row>

<row>

<entry><codeph>NotifyCallAdded() </codeph></entry>

<entry>To get the information about the new calls added to a line. Call the <codeph>NotifyCallAddedCancel()</codeph> function

to cancel an earlier request. </entry>

</row>

</tbody>

</tgroup>

</table></context>