User`s guide

Dialogic
®
System Release 6.0 PCI for Windows
®
Release Update, Rev 62 — January 30, 2008 237
Dialogic Corporation
5. Repeat for each phone call.
Note: Once the ec_setparm( ) is issued with the ECCH_CONVERGE value set to OFF, the
addressed voice channel's echo canceller will no longer track changes in the trunk
characteristics. At the beginning of each new phone call, the application must set
ECCH_CONVERGE to ON to allow the echo canceller to adapt to the connected trunk's
characteristics. Failure to do this can result in poor echo cancellation, which affects
important voice channel functions.
1.63.1.2 Single EC Convergence for JCT Boards
Dialogic
®
D/41JCT-LS Media Boards, and all other JCT boards using a continuous speech
processing firmware load, function with single echo canceller convergence by default.
Therefore it is not necessary to use the ECCH_CONVERGE channel parameter to obtain
single EC convergence. The equivalent to setting the ECCH_CONVERGE parameter to
ON for JCT Boards is to reset the echo canceller prior to every call to ec_stream( ) by
setting the DXCH_EC_TAP_LENGTH parameters.
Note: Calling the ECCH_CONVERGE parameter with JCT Boards will return an error indicating
that this function is not supported.
JCT Boards will function with single EC convergence if you set all the CSP parameters
once at the beginning of each new phone call prior to the first call to ec_stream( ).
If you need continuous EC convergence, set the parameter DXCH_EC_TAP_LENGTH
prior to each call to ec_stream( ). Setting this parameter resets the echo canceller and
forces the echo canceller to reconverge.
1.63.2 Documentation
The online bookshelf provided with Dialogic
®
System Release 6.0 PCI for Windows
®
contains information about all system release features including features for application
development, configuration, administration, and diagnostics.
For more information about ec_stream( ), ec_setparm( ), ec_stopch( ), and other
Dialogic
®
Continuous Speech Processing API functions and parameters, refer to the
following documents:
• Dialogic
®
Continuous Speech Processing API Programming Guide
• Dialogic
®
Continuous Speech Processing API Library Reference
Note: The online bookshelf has not been updated for this feature, so the Continuous Speech
Processing API documentation does not currently include information about the
ECCH_CONVERGE parameter.