Grandstream GXP-2000 is a next generation
enterprise IP telephone based on open industry standards. Built
on innovative technologies, GXP-2000 features market leading superb
audio quality, rich functionalities, and excellent manageability
at affordable prices.
Support SIP (RFC3261), TCP/IP/UDP, RTP/RTCP, HTTP, ARP, ICMP,
DNS (A record and SRV), DHCP(both client and server), 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
GXP-2000EXT Expansion Module - NEW!!

The new GXP-2000EXT Expansion Module features 56 buttons (each
with dual-color LED) that are fully programmable when used with
GXP2000. GXP-2000EXT is connected to and controlled by GXP-2000
via a short cable that comes with the package. Up to 2 GXP-2000EXT
modules can be cascaded with GXP2000, essentially allowing up
to 112 fully programmable phone extensions. The pending new
firmware upgrade for GXP2000 (due out around mid-June) will
support speed dialing, BLF (Busy Lamp Field), call transfer/forward/pickup
on each of the programmable buttons on GXP-2000EXT module.