Grandstream Ucm6304a Ip PBX

User Capacity: Supports up to 1,000 users (or up to 1,500 depending on configuration) with zero-licensing fees.Concurrent Calls: Handles up to 150 concurrent voice calls (or up to 120 calls using secure SRTP encryption).Conferencing Bridge: Accommodates up to 7 distinct voice meeting rooms with up to 120 total participants.Operating System: Powered by the reliable Asterisk version 16 open-source telephony system.