User's Manual Part 2
Table Of Contents
Grandstream Networks, Inc. GXV3175 USER MANUAL    Page 43 of 68 
    FIRMWARE VERSION 1.0.0.32 Updated : 11/2010 
refresher, or select UAS to use the phone as the refresher. 
Force INVITE  The Session Timer can be refreshed using the INVITE or UPDATE 
methods. Select “Yes” to use the INVITE method to refresh the 
session timer 
Caller Request Timer  The default setting is Yes. If Yes is selected, the phone will use the 
session timer when it makes outbound calls if remote party supports 
session timer. 
Callee Request Timer  If Yes is selected, the phone will use the session timer when it 
receives inbound calls with session timer request. 
Force Timer  If Yes is selected, the timer will be activated even if the other party 
does not support session timers. If No is selected, the timer will be 
activated only if the other party supports the timer. To disable the 
timer, Caller Request timer, Callee request timer and Force Timer 
should all be set to No. 
Enable 100rel  The use of the PRACK (Provisional Acknowledgment) method 
enables reliability to SIP provisional responses (1xx series). This is 
very important in order to support PSTN internetworking. To invoke a 
reliable provisional response, the 100rel tag is appended to the value 
of the required header of the initial signaling messages. The default 
setting is No. 
SIP Transport  Selects the SIP transport method. There are three types: TCP, UDP 
and TLS. 
Symmetric RTP  Selects whether or not symmetric RTP is supported. 
Support SIP Instance ID  Selects whether or not SIP Instance ID is supported. 
Validate Incoming 
Messages 
This configuration selects whether or not the incoming messages 
should be validated. 
SIP T1 Timeout  This configures the timeout period for SIP T1. The default setting is 
0.5 Seconds. 
SIP T2 Interval  This configures the time interval for SIP T2. The default setting is 4 
seconds. 
Remove OBP from route  The SIP Extension notifies the SIP server that it is behind a 
NAT/firewall. 
Account/Codec Settings 
Enable Video  --YES: Accepts all incoming video, this is the default setting; 
--NO: video is disabled. 
--Enable/Disable during dialing: Dialing time choice to enable/disable 
video 
DTMF  Assigns the mechanism to send DTMF. There are three supported 
modes: in audio (with DTMF as audio signals), through RTP and 
through SIP INFO. 
DTMF Payload Type  Sends DTMF using RFC2833. The default is 101. 
Preferred Vocoder  This products supports up to 8 different Vocoders: including 
G.711(a/μ)(PCMU/PCMA),GSM,G726-32,G.723.1,G.729A/B, G.722 
and L16-256. 
When this has been configured, the system will select the preferred 
vocoder from the list  and the same order is sent with the SDP 
messages. 
The user can change the preferred vocoder priority order by toggling 










