AudioCodes Mediant 4000 SBC User Manual page 210

CHAPTER 15 Media
■ Statistical accuracy: The number of recorded calls should be as high as possible (at least 100)
and varied. The calls must be made to different people. The calls must be made in the specific
location in which the device's AMD feature is to operate.
■ Real-life recording: The recordings should simulate real-life answering of a called person
picking up the phone, and without the caller speaking.
■ Normal environment interferences: The environment in which the recordings are done should
simulate real-life scenarios, in other words, not sterile but not too noisy either. Interferences,
for example, could include background noises of other people talking, spikes, and car noises.
Once you have provided AudioCodes with your database of recordings, AudioCodes compiles it
into a loadable file. For a brief description of the file format and for installing the file on the device,
see AMD Sensitivity
The device supports up to eight AMD algorithm suites called Parameter Suites, where each suite
defines a range of detection sensitivity levels. Sensitivity levels refer to how accurately the
device's voice detection algorithms can detect if a human or machine has answered the call. Each
level supports a different detection sensitivity to human and machine. For example, a specific
sensitivity level may be more sensitive to detecting human than machine. In deployments where
the likelihood of a call answered by an answering machine is low, it would be advisable to configure
the device to use a sensitivity level that is more sensitive to human than machine. In addition, this
allows you to tweak your sensitivity to meet local regulatory rules designed to protect consumers
from automatic dialers (where, for example, the consumer picks up the phone and hears silence).
Each suite can support up to 16 sensitivity levels (0 to 15), except for Parameter Suite 0, which
supports up to 8 levels (0 to 7). The default, pre-installed AMD Sensitivity file, based on North
American English, provides the following Parameter Suites:
■ Parameter Suite 0 (normal sensitivity) - contains 8 sensitivity detection levels
■ Parameter Suite 1 (high sensitivity) - contains 16 sensitivity detection levels
As Parameter Suite 1 provides a greater range of detection sensitivity levels (i.e., higher detection
resolution), this may be the preferable suite to use in your deployment. The detected AMD type
(human or machine) and success of detecting it correctly are sent in CDR and Syslog messages.
For more information, see
The Parameter Suite and sensitivity level can be applied globally for all calls, or for specific calls
using IP Profiles. For enabling AMD and selecting the Parameter Suite and sensitivity level, see
Configuring
The tables below show the success rates of the default, pre-installed AMD Sensitivity file (based
on North American English) for correctly detecting "live" human voice and answering machine:
Table 15-2: Approximate AMD Normal Detection Sensitivity - Parameter Suite 0 (Based on North Amer-
AMD Detection Sensitivity
(Best for Answering Machine)
File.
Syslog Fields for Answering Machine Detection
AMD.
Level
0
1
2
3
4
ican English)
Performance
Success Rate for Live
Calls
-
82.56%
85.87%
88.57%
88.94%
- 177 -
Mediant 4000 SBC | User's Manual
(AMD).
Success Rate for Answering
Machine
-
97.10%
96.43%
94.76%
94.31%