This is stated in Task based guide BCM50 Rls3
Using the MeetMe Conferencing application, callers can establish a multiparty teleconference up to 18 participants. The conferences can either be wholly internally or a mix of both internal and external callers. Access for internal callers is via the use of F930, external callers access the conference by calling a specified DDI number, alternately by being transferred to a
conference. One caller acts as the chairperson and has additional powers to start, stop, secure, eject and control the conference.