500 concurrent calls and 300 transcoding sessions Which Supports up to 2,000 SIP sessions and 1,500 transcoding sessions, Maximum SIP registrations: 10,000, 128 SIP Trunks at maximum, Embedded VoIP firewall, MCU (Main Control Unit): 2 (Active/Standby), MFU (Main Function Unit): 4,2* 10/100/1000M Base-T Ethernet ports each MCU, 1* USB each MCU, Dual Power Supply