Version 6.4 161 March 2012
SIP User's Manual 12. Media
you can configure AMD per call, based on the called number or Trunk Group. This is
achieved by defining the AMD parameters for a specific IP Profile (IPProfile parameter) and
then assigning the IP Profile to a Trunk Group in the Inbound IP Routing table (PSTNPrefix
parameter).
The device also supports the detection of beeps at the end of an answering machine
message. This allows users of third-party, Application servers to leave voice messages
after an answering machine plays a “beep” sound.
The device supports two methods for detecting and reporting beeps (configured using the
AMDBeepDetectionMode parameter):
Using the AMD detector. This detector is integrated in the existing AMD feature. The
beep detection timeout and beep detection sensitivity are configurable using the
AMDBeepDetectionTimeout and AMDBeepDetectionSensitivity parameters
respectively.
Using the Call Progress Tone detector - several beep tones (Tone Type #46) can be
configured in the CPT file.
The detection of beeps is done using the X-Detect header extension. The device sends a
SIP INFO message containing one of the following field values:
Type=AMD and SubType=Beep
Type=CPT and SubType=Beep
Upon every AMD activation, the device can send a SIP INFO message to an Application
server notifying it of one of the following:
Human voice has been detected
Answering machine has been detected
Silence (i.e., no voice detected) has been detected
The table below shows the success rates of the AMD feature for correctly detecting live
and fax calls:
Table 12-1: Approximate AMD Detection Normal Sensitivity (Based on North American English)
AMD Detection
Sensitivity
Performance
Success Rate for Live Calls Success Rate for Answering Machine
0 (Best for
Answering
Machine)
- -
1
82.56% 97.10%
2
85.87% 96.43%
3 (Default)
88.57% 94.76%
4
88.94% 94.31%
5
90.42% 91.64%
6
90.66% 91.30%
7 (Best for Live
Calls)
94.72% 76.14%
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