User's Manual

FIRMWARE VERSION 1.0.7.6 HT502 USER MANUAL Page 41 of 48
Vocoder in 200OK SDP
200OK response, otherwise it will include all match vocoders in same order received in
INVITE.
Preferred Vocoder
The HT502 supports up to 5 different Vocoder types including G.711 A-/U-law, G.726
(Supports bit rates 16, 24, 32 and 40), G.723.1, G.729A/B/E, iLBC and AAL2. The user
can configure Vocoders in a preference list that will be included with the same
preference order in SDP message. The first Vocoder is entered by choosing the
appropriate option in “Choice 1”. The last Vocoder is entered by choosing the
appropriate option in “Choice 8”.
Vocoder types can also be changed per call basis by using a star code. Please see the
“Call features” section.
Voice Frames per TX
Default is 2, from 1 -4 for G711/G726/G729
G723 Rate Default is 6.3kbps. Defines the encoding rate for G.723 vocoder.
iLBC Frame Size
Sets the iLBC frame size in 20ms or 30ms
iLBC Payload type
Defines payload type for iLBC. Default value is 97. The valid range is between 96 and
127.
AAL2-G726-16 Payload
type
Default value is 100. Range is from 96 to 127.
AAL2-G726 - 24
Payload type
Default value is 99. Range is from 96 to 127.
AAL2-G726 - 32
Payload type
Default value is 104. Range is from 96 to 127.
AAL2-G726 - 40
Payload type
Default value is 103. Range is from 96 to 127.
G729E payload type Default value is 102. Range is from 96 to 127.
VAD Default is No. VAD allows detecting the absence of audio and conserve bandwidth by
preventing the transmission of "silent packets" over the network.
Symmetric RTP Default is No. When set to Yes the device will change the destination to send RTP
packets to the source IP address and port of the inbound RTP packet last received by
the device.
Fax Mode
T.38 (Auto Detect) FoIP by default, or Pass-Through (must use codec PCMU/PCMA)
Fax Tone Detection
Mode
Default is Callee. This decides whether Caller, Callee or both sends out the re-INVITE
for T.38 or Fax Pass Through.
Jitter Buffer Type
Select either Fixed or Adaptive based on network conditions.
Jitter Buffer Length
Select Low, Medium or High based on network conditions.
• 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
This option defines different implementation of support SRTP (squired RTP)