Enterprise-Grade Unified Communication Solution IP PBXs allows businesses of all sizes to build powerful and scalable unified communication solutions in an easy-to-manage fashion with no licensing fees Analog Telephone FXS Ports: 8 RJ11 Port PSTN Line FXO Ports: 8 RJ11 Port Users: 3000 Concurrent calls: 450 Max concurrent SRTP calls: 300 Video Conference: Up to 40 8 Video Conference rooms and up to 60 parties with 1080p, assuming 4 video feeds + 1 screen sharing (H.264 & Opus) Voice Conference: Up to 200 parties (G.711) Three self-adaptive Gigabit ports (switched, routed or dual card mode) with PoE+ 2 USB 3.0, 1SD card interface 128x32 dot matrix graphic LCD with DOWN and OK buttons