User Guide
Grandstream Networks, Inc.  GXP User Manual  Page 11 of 44 
       Firmware 1.2.5.3     Last Updated: 03/2011 
Table 7: GXP Technical Specifications 
Lines 
Multiple direct lines with independent SIP accounts, programmable speed dial keys, 
XML programmable soft-keys (non programmable on GXP-280/285, GXP1200, GXP2000). 
Protocol 
Support 
Support SIP 2.0, TCP/UDP/IP, PPPoE, RTP/RTCP, SRTP by SDES, HTTP, ARP/RARP, 
ICMP, DNS, DHCP, NTP, TFTP, SIMPLE/PRESENCE protocols 
Supports multiple SIP accounts 
  Supports SIP PUBLISH method (RFC 3903), SIP Presence package (RFC 3856, 3863) for 
use of 7 MFKs, SIP Dialog package (RFC 4235)  
Supports  SIP MESSAGE method (RFC 3428) 
Stores up to 100 incoming IM messages 
Display  
Back-lit graphic LCD display. (GXP-280/285 display is not back-lit) 
Feature 
Keys  
  GXP-280/285  GXP-1200  GXP-2000  GXP-2010  GXP-2020 
HOLD  Yes  Yes  Yes  Yes  Yes 
SPEAKERPHONE  Yes  Yes  Yes  Yes  Yes 
SEND  Yes  Yes  Yes  Yes  Yes 
TRANSFER  Yes  Yes  Yes  Yes  Yes 
CONF  Yes  Yes  Yes  Yes  Yes 
MUTE  Yes  Yes  Yes  Yes  Yes 
DND  Yes  Yes  Yes  Yes  Yes 
HEADSET  Yes  Yes  Yes  Yes  Yes 
INTERCOM  No  No  No  Yes  Yes 
PHONEBOOK  No  No  No  Yes  Yes 
MSG  Yes  Yes  Yes  Yes  Yes 
MENU   Yes  Yes  Yes  Yes  Yes 
NAVIGATION (4)  Yes (3)  Yes  Yes  Yes  Yes 
Device  
Management 
NAT-
friendly remote software upgrade (via TFTP/HTTP) for deployed devices including 
behind firewall/NAT 
Auto/manual provisioning system, GUI Interface 
  Support Layer 2 (802.1Q, VLAN, 802.1p) and Layer 3 QoS (ToS, DiffServ, MPLS) 
  Expansion interface, Address Book 
Audio 
Features 
Full-duplex hands-free speakerphone, headset enabled 
Advanced Digital Signal Processing (DSP) 
Dynamic negotiation of codec and voice payload length 
  Support for G.723,1 (5.3/6.3K), G.729A/B, G.711 a/ยต-law, G.726-32, G.722 (wide-band), 
GSM and iLBC codecs 
In-band and out-of-band DTMF (in audio, RFC2833, SIP INFO) 
  Silence Suppression, VAD (voice activity detection), CNG (comfort noise generation), AGC 
(automatic gain control) 
  Acoustic Echo Cancellation (AEC) with Automatic Gain Control (AGC) for speakerphone 
mode, Support side tone 
Adaptive jitter buffer control and packet delay & loss concealment 
Telephony 
Features 
Intuitive graphic user interface (GUI), downloadable phone book (XML, LDAP), support for 
anonymous call using privacy header, MLS (multi language support) 
Voice mail indicator, downloadable custom ring-
tones, call hold, call transfer 










