AudioCodes Mediant 500L MSBR

User's Manual 17. Media
Version 6.8 181 Mediant 500L MSBR
♦ 'Min Reference Delay' (AcousticEchoSuppMinRefDelayx10ms) - defines the
acoustic echo suppressor minimum reference delay
♦ 'Max Reference Delay' (AcousticEchoSuppMaxRefDelayx10ms) - defines
the acoustic echo suppressor maximum reference delay
b. Open the IP Profile Settings page (Configuration tab > VoIP menu > Coders and
Profiles > IP Profile Settings), and set the 'Echo Canceller' field to Acoustic.
c. 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
17.2 Fax and Modem Capabilities
This section describes the device's fax and modem capabilities and corresponding
configuration. The fax and modem configuration is done in the Fax/Modem/CID Settings
page.
Notes:
• Unless otherwise specified, the configuration parameters mentioned in this section
are available on this page.
• Some SIP parameters override these fax and modem parameters. For example,
the IsFaxUsed parameter and V.152 parameters in Section ''V.152 Support'' on
page 193.
• For a detailed description of the parameters appearing on this page, see
''Configuration Parameters Reference'' on page 779.
 To access the fax and modem parameters:
1. Open the Fax/Modem/CID Settings page (Configuration tab > VoIP menu > Media >
Fax/Modem/CID Settings).
2. Configure the parameters, as required.
3. Click Submit.
17.2.1 Fax/Modem Operating Modes
The device supports two modes of operation:

Fax/modem negotiation that is not performed during the establishment of the call.

Voice-band data (VBD) mode for V.152 implementation (see ''V.152 Support'' on page
193): fax/modem capabilities are negotiated between the device and the remote
endpoint at the establishment of the call. During a call, when a fax/modem signal is
detected, transition from voice to VBD (or T.38) is automatically performed and no
additional SIP signaling is required. If negotiation fails (i.e., no match is achieved for
any of the transport capabilities), fallback to existing logic occurs (according to the
parameter IsFaxUsed).