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› Operation in either NBX Call Control mode or Session Initiation Protocol (SIP) › Redundant, hot-swappable power supplies; optional redundant hard disks (RAID1) › Standard four ports by 400 hours AA/VM, scalable up to 72 ports › Dual 10/100 uplink ports; 100 Mbps backplane › Four-slot expansion chassis for additional analog stations or trunks (T1/E1, PRI, BRI, Analog) › 1,500 device capacity (stations/trunks) › SIP-ready for applications and devices *Available in North America and Mexico only.