Grandstream GXP-2000 IP Phone is an award-winning next generation IP network telephone based on industry open standards. Built upon innovative technology, Grandstream IP Phone features market leading superb sound quality and rich functionalities at ultra-affordable price. - SIP 2.0, TCP/UDP/IP, RTP/RTCP, HTTP, ARP/RARP, ICMP, DNS (A record and SRV), DHCP, NTP, TFTP protocols - 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 10/100 Mbps 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-Ethernet (802.3af and Cisco style)