Managing conferences

This topic presents:

• Setting conference attributes

• Setting member attributes

• Playing a tone

• NaturalConference events

• Closing a conference

Setting conference attributes

Conferences are created with both parameters and attributes. Conference parameters contain information about a given conference, and cannot change over the life of the conference. Attributes denote certain special characteristics that a given conference possesses, and change frequently during the life of the conference.

You retrieve conference parameters and other information together in a corresponding CNF_CONFERENCE_INFO structure, while you access attributes individually.

You can assign the following types of attributes to a conference:

• Loudest speaker

• Event mask

• Active talkers

• Active talkers timer

For a description of conference attributes, refer to cnfGetConferenceAttribute.

The following table lists the functions for accessing conference information and attributes:

Setting member attributes

Information and attributes associated with members differ in the same way they do for conferences. Members are created with both parameters and attributes. While member parameters cannot change over the life of the conference, member attributes change frequently during the life of the conference.

You retrieve member parameters and other information together in a corresponding CNF_MEMBER_INFO structure, while you access attributes individually.

You can assign the following types of attributes to conference members:

• Automatic gain control

• Talking and listening control

• Talker privileges

• DTMF clamping

• Tone clamping

• Echo cancellation

• Self echo

• G.711 law

For a detailed description of the member attributes, refer to cnfGetMemberAttribute.

The following table lists the functions for accessing member information and attributes:

Playing a tone

Call cnfStartTone to play a tone to all members of a conference to indicate that a new member is joining or leaving the conference. When cnfStartTone is invoked, members stop hearing each other and hear only the tone.

Tone attributes are stored in the CNF_TONE_PARMS structure. You can also set default parameters for the tone attributes.

The following table lists the functions to call to play a tone:

NaturalConference events

NaturalConference uses the Natural Access event reporting mechanism, ctaWaitEvent. ctaWaitEvent returns the CTA_EVENT structure informing the application about which event occurred on which context. The structure includes information specific to the event.

Some events are generated only by setting the appropriate bit in the CNF.CONFERENCE_ATTR event_mask parameter or by modifying the CONF_ATTR_EVENT_MASK attribute using cnfSetConferenceAttribute.

NaturalConference generates the following events:

When receiving CNFEVN_ACTIVE_TALKERS_CHANGE, you can retrieve the actual list of members that are active talkers by calling cnfGetActiveTalkersList. If the space available for retrieving the list of members is large enough, the number of memberid fields filled by the function and returned in nummemberids is the number of members speaking, as defined by the attribute CONF_ATTR_ACTIVE_TALKERS value currently set for that conference. The returned list contains the member that is the active talker when the function is called. The active talker lists are not queued in NaturalConference.

Closing a conference

To close a conference, follow these steps:

Conference and call completion

Although a conference merges voices coming from different calls, there is no direct relationship between individual calls and conference members. The application features and scenarios drive the way calls and members are created and destroyed. A call can be added or removed from the same or different conferences without having to be released. When a call is disconnected, the application should force the corresponding members to leave the conference as soon as possible.

The following table lists the functions to call when closing a conference: