Answer Machine Detector (Amd) - AudioCodes Mediant 2000 User Manual

SIP User's Manual

12.4.1 Answer Machine Detector (AMD)

The device provides answering machine detection (AMD) capabilities that can detect for
example, if a human voice or an answering machine is answering the call. AMD is useful
for automatic dialing applications.
The device supports up to four AMD parameter suites, where each parameter suite defines
the AMD sensitivity levels of detection. The detection sensitivity levels can range from 0 to
15, depending on parameter suite. The level is selected using the AMDSensitivityLevel
parameter. The Parameter Suite(s) can be loaded to the device in the Web interface as an
auxiliary file (see ''Loading Auxiliary Files'' on page 351) or loaded remotely through the ini
file (using the AMDSensitivityFileName and AMDSensitivityFileUrl parameters). In addition,
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
0 (Best for
Answering
Machine)
1
2
3 (Default)
Version 6.4
Success Rate for Live Calls
-
82.56%
85.87%
88.57%
Performance
Success Rate for Answering Machine
153
12. Media
-
97.10%
96.43%
94.76%
November 2011