Is openfire 3.7.1 support voice chat with jingle? any developer's guide?

We used openfire as the xmpp server, and developed the client im with SWT, Now, it all worked fine. Now we want to support voice chating with jingle. Is there any document how it achieve this?

 We have tried configing a STUN server in openfire, and tried spark 2.6.3, but we even can not see call button in chatting dialog, could somebody please give some instructions?

Thank you.