User's Manual
Grandstream Networks, Inc.  HT-702 User Manual  Page 27 of 32 
  Firmware Version 1.0.0.17  Last Updated: 02/2012 
G723 Rate  Default is 6.3kbps. Defines the encoding rate for G.723 vocoder. 
iLBC Frame Size 
Sets the iLBC frame size in 20ms or 30ms 
iLBC Payload type 
Defines payload type for iLBC. Default value is 97. The valid range is between 96 and 
127. 
VAD  Default is No. VAD allows detecting the absence of audio and conserve bandwidth by 
preventing the transmission of "silent packets" over the network. 
Symmetric RTP  Default is No. When set to Yes the device will change the destination to send RTP 
packets to the source IP address and port of the inbound RTP packet last received by 
the device. 
Fax Mode 
T.38 (Auto Detect) FoIP by default, or Pass-Through (must use codec PCMU/PCMA) 
Re-Invite after Fax Tone 
Detection Mode 
Default is Enabled.  It makes the unit send out the re-INVITE for T.38 or Fax Pass 
Through if a fax tone is detected. 
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) 
SRTP Mode 
This option defines different implementation of support SRTP (squired RTP) 
transmission mode. 
SLIC Setting 
Dependent on standard phone type (and location) 
Caller ID Scheme 
Bellcore/Telcordia, ETSI-FSK, ETSI-DTMF, SIN 227 – BT, & NTT Japan 
Polarity Reversal  Default is No. If set to “Yes”, polarity will be reversed upon call establishment and 
termination. 
Loop Current 
Disconnect 
Default is No. Set it to Yes if the traditional PBX you are using with HT702 uses this 
method for signaling call termination. Method initiates short voltage drop on the line 
when remote (VoIP) side disconnects an active call. 
Loop Current 
Disconnect Duration 
Here can be configured duration of such voltage drop described in topic above. 
Hook Flash Timing 
Time period when the cradle is pressed (Hook Flash) to simulate FLASH. To prevent 
unwanted activation of the Flash/Hold and automatic phone ring-back, adjust this time 
value. 
On Hook Timing 
On-hook timing is the minimum time for an on-hook event to be validated. 
Gain 
Voice path volume adjustment. 
•  Rx is a gain level for signals transmitted by FXS 
•  Tx is a gain level for signals received by FXS. 
Default = 0dB for both parameters. Loudest volume: +6dB Lowest volume: -6dB. 
User can adjust volume of call on either end using the Rx Gain Level parameter and 
the Tx Gain Level parameter located on the FXS Port Configuration page. 
If call volume is too low when using the FXS port (ie. the ATA is at user site), adjust 
volume using the Rx Gain Level parameter under the FXS Port Configuration page. 
If voice volume is too low at the other end, user may increase the far end volume using 
the Tx Gain Level parameter under the FXS Port Configuration page. 
Disable Line Echo 
Canceller (LEC) 
Default is No.  If set to “Yes” LEC will be disabled per call base. Recommended for 
FAX/Data calls. 
Ring Tones 
This function lets you configure ring tone cadence preferences. User has 10 choices. 










