To host a moderated conference call, set the call to start only when the moderator joins by using the attribute startConferenceOnEnter="true". You can also set the call to end when the moderator hangs up with the attribute endConferenceOnExit="true".
For the moderator, the XML should be as shown below.
<Response>
<Conference startConferenceOnEnter="true" endConferenceOnExit="true">My Room</Conference>
</Response>
For other participants, use the following XML.
<Response>
<Conference startConferenceOnEnter="false" waitSound="https://yourdomain.com/waitmusic/">My Room</Conference>
</Response>