Grandstream Networks HT813 Administration Manual page 38

Disable
Disables OPUS stereo in SDP.
OPUS
Stereo in
Default is No.
SDP
iLBC
Determines payload type for iLBC. Valid range is between 96 and 127.
Payload
Default is 97.
type
OPUS
Payload Determines payload type for OPUS. Valid range is between 96 and 127. Default is 123.
Type
Allows detecting the absence of audio and conserves bandwidth by preventing the transmission of "silent
VAD
packets" over the network. Default is No.
Symmetric Changes the destination to send RTP packets to the source IP address and port of the inbound RTP packet
RTP last received by the device. Default is No.
Fax Mode Specifies the fax mode: T.38 (Auto Detect) FoIP by default, or Pass-Through (must use codec PCMU/PCMA)
Re-INVITE
after Fax Allows the unit to send out the re-INVITE for T.38 or Fax Pass Through if a fax tone is detected. Default is
Tone Enabled
Detected
Jitter
Selects jitter buffer type (Fixed or Adaptive) based on network conditions.
Buffer Type
High (initial 200ms, min 40ms, max 600ms) Note: not all vocoders can meet the high requirement.
Jitter
Buffer Medium (initial 100ms, min 20ms, max 200ms).
Length
Low (initial 50ms, min 10ms, max 100ms).
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
SRTP Mode
SDES: https://tools.ietf.org/html/rfc4568
SRTP: https://www.ietf.org/rfc/rfc3711.txt
Configures the SRTP Key Length , it can be set to :
1. AES 128&256 bit
SRTP Key
2. AES 128 bit
Length
3. AES 256 bit
Default value is AES 128&256 bit
Crypto Life
Adds crypto life time header to SRTP packets. Default is Yes.
Time