Grandstream UCM6308 IP PBX 8 x FXS and 8 x FXO ports Voice and Fax Codec Maximum Call Capacity: Users: Users: 3000, Concurrent calls (G.711): 450, Max concurrent SRTP calls (G.711), 300 Maximum Attendees of Conference Bridges: Up to 25 simultaneous video conference rooms, up to 300 simultaneous participants in all rooms combined, up to 9 video...