AudioCodes Mediant 4000 SBC User Manual page 182

echo. The device removes these echoes and sends only the near-end's desired speech
signal to the network (i.e., to the far-end party). The echo is composed of a linear part and
a nonlinear part. However, in the Acoustic Echo Canceler, a substantial part of the echo is
non-linear echo. To support this feature, the Forced Transcoding feature must be enabled
so that the device uses DSPs.
The following procedure describes how to configure echo cancellation through the Web
interface:

To configure echo cancellation:
1. Configure line echo cancellation:
a. Open the Voice Settings page (Setup menu > Signaling & Media tab > Media
folder > Voice Settings).
b. From the 'Echo Canceller' drop-down list (EnableEchoCanceller), select Enable.
2. Enable acoustic echo cancellation for SBC calls:
a. Open the Voice Settings page (Setup menu > Signaling & Media tab > Media
folder > Voice Settings).
b. Under the Network Echo Suppressor group:
c. In the Voice Settings page, configure the following parameters:
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d. Open the IP Profiles table, and configure the 'Echo Canceller' parameter to
Acoustic (see Configuring IP Profiles on page 418).
e. Enable the Forced Transcoding feature (using the TranscodingMode parameter)
to allow the device to use DSP channels, which are required for acoustic echo
cancellation.
Note: The following additional echo cancellation parameters are configurable only
through the ini file:
•
ECHybridLoss - defines the four-wire to two-wire worst-case Hybrid loss
•
ECNLPMode - defines the echo cancellation Non-Linear Processing (NLP) mode
•
EchoCancellerAggressiveNLP - enables Aggressive NLP at the first 0.5 second of
the call
User's Manual
Figure 14-2: Enabling Echo Cancellation
Figure 14-3: Enabling Echo Canceller
'Network Echo Suppressor Enable' (AcousticEchoSuppressorSupport) -
enables the network Acoustic Echo Suppressor
'Echo Canceller Type' (EchoCancellerType) - defines the echo canceller type
'Attenuation Intensity' (AcousticEchoSuppAttenuationIntensity) - defines the
acoustic echo suppressor signals identified as echo attenuation intensity
'Max ERL Threshold' (AcousticEchoSuppMaxERLThreshold) - defines the
acoustic echo suppressor maximum ratio between signal level and returned
echo from the phone
'Min Reference Delay' (AcousticEchoSuppMinRefDelayx10ms) - defines the
acoustic echo suppressor minimum reference delay
'Max Reference Delay' (AcousticEchoSuppMaxRefDelayx10ms) - defines
the acoustic echo suppressor maximum reference delay
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Mediant 4000 SBC
Document #: LTRT-40203