Grandstream GXP21xx Series User Manual User Manual
Page 55

FIRMWARE VERSION 1.0.8.4 GXP2120/GXP2110/GXP2100/GXP14xx USER MANUAL
Page 53 of 85
"refreshed" via a SIP request (UPDATE, or re-INVITE). If there is no refresh 
via an UPDATE or re-INVITE message, the session will be terminated once 
the session interval expires. Session Expiration is the time (in seconds) where 
the session is considered timed out, provided no successful session refresh 
transaction occurs beforehand. The default value is 180 seconds. 
Min-SE
The minimum session expiration (in seconds). The default value is 90 
seconds. 
Caller Request Timer
If set to "Yes" and the remote party supports session timers, the phone will use 
a session timer when it makes outbound calls. 
Callee Request Timer
If set to "Yes" and the remote party supports session timers, the phone will use 
a session timer when it receives inbound calls. 
Force Timer
If Force Timer is set to "Yes", the phone will use the session timer even if the 
remote party does not support this feature. If Force Timer is set to "No", the 
phone will enable the session timer only when the remote party supports this 
feature. To turn off the session timer, select "No". 
UAC Specify Refresher
As a Caller, select UAC to use the phone as the refresher; or select UAS to 
use the Callee or proxy server as the refresher. 
UAS Specify Refresher
As a Callee, select UAC to use caller or proxy server as the refresher; or select 
UAS to use the phone as the refresher. 
Force INVITE
The Session Timer can be refreshed using the INVITE method or the UPDATE 
method. Select "Yes" to use the INVITE method to refresh the session timer. 
Account x -> SIP Settings -> Security Settings
Check Domain 
Certificates 
Choose whether the domain certificates will be checked or not when TLS/TCP 
is used for SIP Transport. The default setting is "No". 
Validate Incoming 
Messages 
Choose whether the incoming messages will be validated or not. The default 
setting is "No". 
Check SIP User ID for 
incoming INVITE 
If set to "Yes", SIP User ID will be checked in the Request URI of the incoming 
INVITE. If it doesn't match the phone's SIP User ID, the call will be rejected. 
The default setting is "No". 
Accept Incoming SIP 
from Proxy Only 
When set to "Yes", the SIP address of the Request URL in the incoming SIP 
message will be checked. If it doesn't match the SIP server address of the 
account, the call will be rejected. The default setting is "No". 
Authenticate Incoming 
INVITE 
If set to "Yes", the phone will challenge the incoming INVITE for authentication 
with SIP 401 Unauthorized response. The default setting is "No". 
Account x -> Audio Settings
Send DTMF
Specifies the mechanism to transmit DTMF digits. There are 3 supported 
modes: in audio which means DTMF is combined in the audio signal (not very 
