Polycom SOUNDPOINT SIP 2.2.0 - Manual (Page 159)

Configuration Files
A - 47
Voice Activity Detection
These settings control the performance of the voice activity detection (silence
suppression) feature.
Quality of Service
These settings control the Quality of Service (QOS) options.
This attribute includes:
• Ethernet IEEE 802.1p/Q
• IP TOS
Ethernet IEEE 802.1p/Q
The following settings control the 802.1p/Q user_priority field:
• RTP
• Call Control
• Other
Attribute
Permitted
Values
Default Interpretation
voice.vadEnable 0, 1 0 If set to 1, enable VAD.
voice.vadThresh integer from 0
to 30 15 The threshold for determining what is active voice and
what is background noise in dB. This does not apply to
G.729AB codec operation which has its own built-in VAD
function.
voice.vad.signalAnnex
B 0, 1 Null If set to 1 and voice.vadEnable is set to 1, Annex B is
used. A new line can be added to SDP depending on the
setting of this parameter and the voice.vadEnable
parameter.
• If voice.vadEnable is set to 1, add attribute line
a=fmtp:18 annexb="yes" below a=rtpmap… attribute
line (where '18' could be replaced by another
payload).
• If voice.vadEnable is set to 0, add attribute line
a=fmtp:18 annexb="no" below a=rtpmap… attribute
line (where '18' could be replaced by another
payload).
If set to 0 or Null, there is no change to SDP.