IP Phone User Manual
Grandstream Networks, Inc.  GXP1400/1405 User Manual   Page 29 of 36 
   Firmware version: 1.0.1.83  Last Updated: 08/2011 
Support SIP Instance ID 
Selects whether or not SIP Instance ID is supported.  
NAT Traversal 
This parameter activates the NAT traversal mechanism. It has options: No, STUN, 
Keep-Alive, UPnP, Auto, VPN.  
If selecting STUN and a STUN server is also specified, the phone performs 
according to the STUN client specification. Using this mode, the embedded STUN 
client detects if and what type of NAT/Firewall configuration is used. If the detected 
NAT is a Full Cone, Restricted Cone, or a Port-Restricted Cone, the phone will use 
its mapped public IP address and port in all of its SIP and SDP messages.  
If selecting Keep-
Alive with no specified STUN server, the GXP1400/1405 will 
periodically (every 20 seconds or so
) send a blank UDP packet (with no payload 
data) to the SIP server to keep the “hole” on the NAT open. 
SUBSCRIBE for MWI 
Default is “No”. When set to “Yes”, a SUBSCRIBE for Message Waiting Indication 
will be sent periodically. 
SUBSCRIBE for 
Registration 
Default is “No”. When set to “Yes” a SUBSCRIBE for Registration will be sent 
periodically. 
Feature Key 
Synchronization 
Default is “No”. This option is to synchronize DND/Call Forward features with 
Broadsoft. When set to “Yes”, a SUBSCRIBE will be sent out 
periodically to the 
server. Then when DND/Call Forward features (Call Forward No Answer, 
Unconditional Call Forward and Call Forward on Busy) are configured or changed 
on the phone and the Broadsoft server side, those features will be synchronized on 
the phone side and the Broadsoft server side. 
PUBLISH for Presence 
Enable Presence feature. 
Proxy-Require 
SIP Extension to notify SIP server that the unit is behind the NAT/Firewall. 
Voice Mail UserID 
When configured, user can access messages by pressing “MSG” button. This ID is 
usually the VM portal access number. 
Send DTMF 
This parameter specifies the mechanism to transmit DTMF digit. There are 3 
supported modes: in audio which means DTMF is combined in audio signal (not 
very reliable with low-bit-rate codec), via RTP (RFC2833), or via SIP INFO.  
DTMF Payload Type 
Sends DTMF using RFC2833. The default is 101.  
Early Dial 
Default is “No”. Use only if proxy supports 484 responses. 
Dial Plan Prefix 
Sets the prefix added to each dialed number. 










