The phone only works with VoIP 2 dual-color line keys (with 2 SIP accounts and up to 2 call appearances), 3 XML programmable context-sensitive soft keys, 3-way conference HD wideband audio, superb full-duplex hands-free speakerphone with advanced acoustic echo cancellation and excellent double-talk performance. Large phonebook (up to 500 contacts) and call history - up to 200 records Automated provisioning using TR-069 or encrypted XML configuration file, SRTP and TLS for advanced security protection, 802.1x for media access control 13248 pixel backlit graphical LCD display.