For the IP500 and IP500 V2 the total conferencing capacity is 128 channels with either Essential or Preferred Edition licensing. This could be alternatively 2 conference of 64 users, 3 conferences of 42 users or any other combination (maximum 64 participants per conference call). A PRI or SIP Trunks are required. When only CO lines are present the max number of outside callers is 2.
Replied on Nov 16, 2021 by Ann from TelecomEx