User manual

Grandstream Networks, Inc. GXP1100/1105 User Manual Page 30 of 34
Firmware version: 1.0.1.110 Last Updated: 01/2012
Check SIP User ID for
Incoming INVITE
Check the SIP User ID in Request URI. If they don’t match, the call will be rejected.
Preferred Vocoder
GXP1100/1105 supports up to 7 different Vocoder types including G.711(a/µ) (also
known as PCMU/PCMA), G.723.1, G.729A/B, G.726-32, iLBC, G.722 (wide-band).
Configure Vocoders in a preference list that is included with the same preference
order in SDP message. Enter the first Vocoder in this list by choosing the
appropriate option in “Choice 1”. Similarly, enter the last Vocoder in this list by
choosing the appropriate option in “Choice 8”.
SRTP Mode
Enable SRTP mode based on selection. Default is “No”.
Symmetric RTP
Selects whether or not symmetric RTP is supported.
Silence Suppression
This controls the silence suppression/VAD feature of the audio codec G.723 and
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.
Voice Frames per TX
This field contains the number of voice frames to be transmitted in a single Ethernet
packet (be advised the IS limit is based on the maximum size of Ethernet packet is
1500 byte (or 120kbps)).
When setting this value, be aware of the requested packet time (ptime, used in SDP
message) is a result of configuring this parameter. This parameter is associated
with the first codec in the above codec Preference List or the actual used payload
type negotiated between the 2 conversation parties at run time. E.g., if the first
codec is configured as G.723 and the “Voice Frames per TX” is set to 2, then the
“ptime” value in the SDP message of an INVITE request will be 60ms because each
G.723 voice frame contains 30ms of audio. Similarly, if this field is set to 2 and the
first codec is G.729 or G.711 or G.726, then the “ptime” value in the SDP message
of an INVITE request will be 20ms.
If the configured voice frames per TX exceeds the maximum allowed value, the IP
phone will use and save the maximum allowed value for the corresponding first
codec choice. The maximum value for PCM is 10 (x10ms) frames; for G.726, it is 20
(x10ms) frames; for G.723, it is 32 (x30ms) frames; for G.729/G.728, 64 (x10ms)
and 64 (x2.5ms) frames respectively.
Please be careful when editing these parameters. Adjusting these parameters will
also change the dynamic jitter buffer. The GXP1100/1105 has a patent dynamic
jitter buffer handling algorithm. The jitter buffer range is 20 ~ 200 ms.
We recommend using the default settings provided. We do not recommend
adjusting these parameters if you are an average user. Incorrect settings will affect
the voice quality.
No Key Entry Timeout
Default is 4 seconds.
Use # as Dial Key
This parameter allows users to configure the “#” key as the “Send” (or “Dial”) key. If
set to “Yes”, the “#” key will immediately send the call. In this case, this key is
essentially equivalent to the “(Re)Dial” key. If set to “No”, the “#” key is included as
part of the dial string.