Grandstream GXP2130 Administration Guide - Manual (Page 39)

GXP2130/GXP2140/GXP2160
FIRMWARE VERSION 1.0.4.23 GXP2130/GXP2140/GXP2160
ADMINISTRATION GUIDE Page 37 of 81
Account x -> Audio Settings
Send DTMF
This parameter 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.
• In audio, which means DTMF is combined in the audio signal (not very
reliable with low-bit-rate codecs);
• RFC2833, which means to specify DTMF with RTP packet. Users could know
the packet is DTMF in the RTP header as well as the type of DTMF;
• SIP INFO, which use SIP info to carry DTMF. The defect of this mode is that
it's easily to cause desynchronized of DTMF and media packet for the reason
the SIP and RTP are transmitted respectively. The default setting is
"RFC2833".
DTMF Payload Type
This parameter sets the payload type for DTMF using RFC2833. Default is
101. The valid range is from 96 to 127.
Preferred Vocoder
Multiple vocoder types are supported on the phone, the vocoders in the list is a
higher preference. 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
Enable SRTP mode based on your selection from the drop-down menu. The
default setting is "Disabled".
Crypto Life Time
Enable or disable the crypto life time when using SRTP. If users set to disable
this option, phone does not add the crypto life time to SRTP header. The
default setting is “Yes”.
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
users, it is recommended to use the default setting, as incorrect settings may