User's Manual
Table Of Contents
FIRMWARE 1.0.3.4  GXW42XX USER MANUAL  PAGE 43 OF 56 
SRTP Mode 
Default is Disabled. Other options are Enabled but not forced, and Enabled and forced.  
It uses SDP Security Description to exchange key. Please refer  
SDES: http://www.apps.ietf.org/rfc/rfc4568.html 
SRTP: http://www.apps.ietf.org/rfc/rfc3711.html  
Silence 
Suppression 
(VAD) 
Default is No.  VAD allows detecting the absence of audio and conserve bandwidth by 
preventing the transmission of "silent packets" over the network. 
Jitter Buffer Type 
Select either Fixed or Adaptive based on network conditions. 
Jitter Buffer 
Length 
Select Low, Medium or High based on network conditions. 
• 
High (initial 200ms, min 40ms, max 600ms) Note: not all vocoders can meet the high 
requirement 
•  Medium (initial 100ms, min 20ms, max 200ms) 
•  Low (initial 50ms, min 10ms, max 100ms) 
SLIC Setting 
Depends on standard phone type (and location) 
Caller ID Scheme 
Select the value according to the local Telco standard where the GXW4248 is installed.  
Please refer to the pull down list to select.  
Polarity Reversal 
Default is No. If set to “Yes”, polarity will be reversed upon call establishment and termination. 
Loop Current 
Disconnect 
Set to Yes if the traditional PBX you are using with GXW4248 uses this method for signaling 
call termination. Default is No. 
Loop Current 
Disconnect 
duration 
Default is 200. In 100 - 1 0000 milliseconds range. 
Enable Hook 
Flash 
If no, flash will be treated as an on hook event. 
Hook Flash timing 
(Minimum)/ 
(Maximum) 
Sets the minimum/maximum time the phone is on hook before being detected as a hook flash. 
The range is 40 to 2000 milliseconds 
On Hook Timing 
Sets the time required to detect that the phone is on hook. The range is 40 to 2000 
milliseconds. Default is 400 milliseconds. 










