User Guide
Grandstream Networks, Inc.  GXP User Manual  Page 40 of 44 
       Firmware 1.2.5.3     Last Updated: 03/2011 
UAS Specify Refresher 
As a Callee, select UAC to use caller or proxy server as the refresher, or UAS to 
use the phone as the refresher. 
Force INVITE 
Session Timer can be refreshed using INVITE method or UPDATE method. 
Select “Yes” to use INVITE method to refresh the session timer.  
Enable 100rel 
PRACK (Provisional Acknowledgment) method enables reliability to SIP 
provisional responses (1xx series). This is required to support PSTN inter-
networking.. 
Account Ring Tone 
There are 4 uniquely defined ring tones: 
•  One (1) System Ring Tone: when selected, all calls will ring with system 
ring tone. 
•  Three (3) Customer Ring Tones: when selected, incoming calls from 
designated account will play selected ring tone.  
Ring Timeout 
Defines how long ring will ring when receiving a call. Default is 60 seconds. 
Send Anonymous 
If this parameter is set to “Yes”, the “From” header in outgoing INVITE message 
will be set to anonymous, essentially blocking the Caller ID from displaying. 
Anonymous Method 
Whether to use “<sip:anonymous@anonymous.invalid>” in the From Header or P-
Asserted-Identity header. 
Anonymous Call 
Rejection 
Default is NO. If set to YES, anonymous call will be rejected 
Auto Answer 
Default is No.  If set to “Yes”, GXP will automatically switch on speaker to answer 
the incoming call. Set to Intercom/Paging mode, it will answer the call based on 
the SIP info header from the server.  
Allow Auto Answer by 
Call-Info 
If the Call-Info header contains answer-after=0, the call be answered 
automatically (so called paging mode). 
Turn off speaker on  
remote disconnect 
When BYE is received, the phone will turn off its speaker automatically. 
Check SIP User ID for  
incoming INVITE 
Check the SIP User ID in Request URI. If they don’t match, the call will be 
rejected. 
Refer-To Use Target 
Contact 
Default is NO. If set to YES, then for Attended Transfer, the “Refer-To” header uses the 
transferred target’s Contact header information. 
Disable Multiple Media 
Attribute in SDP 
Default is No. 
Preferred Vocoder 
GXP supports up to 7 different Vocoder types including G.711(a/µ) (also known 
as PCMU/PCMA), GSM, G.723.1, G.729A/B, G.726-32, iLBC, G.722 (wide-band).
Configure Vocoders in a preference list that is included with the same preference 
order in SDP message. Enter the first Vocoder in this list by choosing the 
appropriate option in “Choice 1”. Similarly, enter the last Vocoder in this list by 
choosing the appropriate option in “Choice 8”.  
SRTP Mode 
Enable SRTP mode based on selection. Default is No.  










