User's Manual
FIRMWARE VERSION 1.0.0.3 GXP2140 USER MANUAL   Page 45 of 77 
Account x -> SIP Settings -> Security Settings 
Check Domain 
Certificates 
Defines 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 
Defines 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 
reliable with low-bit-rate codecs), via RTP (RFC2833), or via SIP INFO. 
DTMF Payload Type 
Configures the payload type for DTMF using RFC2833. The default value is 
101. 
Preferred Vocoder 
7 different vocoder types are supported on the phone, including G.711 U-law 
(PCMU),  G.711  A-law  (PCMA),  G.729A/B,  G.722  (wide  band)  and  G72-32. 
Users  can  configure  vocoders  in  a  preference  list  that  is  included  with  the 
same preference order in SDP message. 
Use First Matching 
Vocoder in 200OK SDP 
When  set  to  "Yes",  the  device  will  use  the  first  matching  vocoder  in  the 
received 200OK SDP as the codec. The default setting is "No". 
SRTP Mode 
Enables  the  SRTP  mode  based  on  your  selection.  The  default  setting  is 
"Disabled". 
Symmetric RTP 
Defines  whether  symmetric  RTP  is supported  or  not.  The  default  setting  is 
"No". 
Silence Suppression 
Controls the silence suppression/VAD feature of the audio codec G.729. If set 
to "Yes", when silence is detected, a small quantity of VAD packets (instead of 
audio packets) will be sent during the period of no talking. If set to "No", this 
feature is disabled. The default setting is "No". 
Voice Frames Per TX 
Configures  the  number  of  voice  frames  transmitted  per  packet.  When 
configuring  this,  it  should  be  noted  that  the  "ptime"  value  for  the  SDP  will 
change with different configurations here. This value is related to the codec 
used  and  the actual  frames  transmitted during  the in  payload call.  For  end 










