Grandstream Networks HT881

RFC2833 End Events Count This feature allows users to customize the count of RFC2833 end events. Default is 3.
Preferred Vocoder
Preferred Vocoder (in listed order)
Congures vocoders in a preference list (up to 8 preferred vocoders) that will be included with same order in
SDP message. Vocoder types are G.711 A-/U-law, G.726-32, G.723, G.729, iLBC and OPUS
Voice Frames per TX
Transmits a specic number of voice frames per packet. Default is 2; increases to 10/20/32/64 for
G711/G726/G723/other codecs respectively.
G723 Rate
Operates at specied encoding rate for G.723 vocoder. Available encoding rates are 6.3kbps or 5.3kbps.
Default is6.3kbps.
iLBC Frame Size Species iLBC packet frame size (20ms or 30ms). Default is 20ms.
Disable OPUS Stereo in SDP Disables OPUS stereo in SDP. Default is No.
iLBC Payload Type
Determines payload type for iLBC. Valid range is between 96 and 127.
Default is97.
OPUS Payload Type Determines payload type for OPUS. Valid range is between 96 and 127. Default is 123.
Enable Audio RED with FEC
Enables the use of audio redundancy (RED) with forward error correction (FEC) to enhance audio quality and
resilience against packet loss in real-time communication systems such as VoIP
Audio FEC Payload Type
Species the payload type used for transmitting audio forward error correction (FEC) packets in a VoIP
system.
Audio RED Payload Type Denes the payload type assigned to audio redundancy (RED) packets in a VoIP system,
VAD
Allows detecting the absence of audio and conserves bandwidth by preventing the transmission of “silent
packets” over the network.
Default isNo.
Use First Matching Vocoder in
200OK SDP
Includes only the rst matching vocoder in its 200OK response, otherwise it will include all matching vocoders
in same order received in INVITE.
Default isNo.
Symmetric RTP
Changes the destination to send RTP packets to the source IP address and port of the inbound RTP packet
last received by the device. Default is No.
Enable RTCP Allows users to enable RTCP. The default setting is “Yes”.
Fax Mode
Species the fax mode: T.38 (Auto Detect) FoIP by default, or Pass-Through. If using Pass-through mode,
select preference codec as PCMU or PCMA.
Re-INVITE After Fax Tone Detected
Permits the unit to send out the re-INVITE for T.38 or Fax Pass Through if a fax tone is detected. Default is
Enabled
Jitter Buffer Type Selects jitter buffer type (Fixed or Adaptive) based on network conditions.
Jitter Buffer Length
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 Selects SRTP mode to use (“Disabled”, “Enabled but not forced”, or “Enabled and forced”). Default isDisabled
It uses SDP Security Description to exchange key. Please refer to