full-featured 4-line Business-class Ip Phone Supporting Power Over Ethernet (poe)connects Directly To An Internet Telephone Service Provider Or To An Ip Pbxdual Gigabit Ethernet Switched Ports, Speakerphone, Caller Id, Call Hold, Conferencing, And Moreeasy Installation And Secure Remote Provisioning, As Well As Menu-based And Web-based Configurationsupports Up To Two Cisco Spa500s Expansion Modules Adding Up To 64 Additional Keyssupports Both Sip And Spcp Protocol With Cisco Unified Communication 500 Series