Support SIP (RFC3261), TCP/IP/UDP, RTP/RTCP, HTTP, ARP, ICMP, DNS (A record and SRV), DHCP, PPPoE, TFTP, NTP
Support NAT traversal (STUN, etc), server fail-over, SIP presence (SIMPLE), and more
Multiline support of up to 11 lines indicators (expandable to a few dozen more through expansion key-module)
Graphical LCD to display up to 8 lines and 22 characters per line
Dual 10/100Mbps Ethernet ports
Headset jack
Support Caller ID display or block, per call or permanent
Call waiting, Hold, Mute, Transfer (blind or attended), Forward, and more
Multi-party conferencing
Integrated Power-over-Ether (802.3af)
And many more enterprise grade features