.. _hwec_configuration:

**************************
Hardware Echo-cancellation
**************************

It is *recommended* to use telephony cards with an hardware echo-canceller module.

.. warning:: with **TE13x, TE23x and TE43x** cards, you **MUST** install the echo-canceller firmware.
    Otherwise the card won't work properly.


Know which firmware you need
============================

If you have an hardware echo-canceller module you **have to** install its firmware.

You first need to know which firmware you have to install.
The simplest way is to restart dahdi and then to lookup in the dmesg which
firmware does DAHDI request at startup::

   wazo-service restart
   dmesg |grep firmware
   [5461540.738209] wct4xxp 0000:01:0e.0: firmware: agent aborted loading dahdi-fw-oct6114-064.bin (not found?)
   [5461540.738310] wct4xxp 0000:01:0e.0: VPM450: firmware dahdi-fw-oct6114-064.bin not available from userspace

In the example above you can see that the module ``wct4xxp`` requested the ``dahdi-fw-oct6114-064.bin``
firmware file but did not found it.
But you now know that you need the ``dahdi-fw-oct6114-064.bin`` firmware.


Install the firmware
====================

When you know which firmware you need you can install it with ``xivo-fetchfw`` utility.

#. Use ``xivo-fetchfw`` to find the name of the package. You can search for ``digium``
   occurrences in the available packages::

    xivo-fetchfw search digium

#. Find the package name which matches the firmware file you need. In our example, we need the
   ``dahdi-fw-oct6114-064.bin`` file which is supplied by the package named ``digium-oct6114-064``::

    xivo-fetchfw install digium-oct6114-064


Activate the Hardware Echo-cancellation
=======================================

Now that you installed hardware echo-canceller firmware you must activate it
in :file:`/etc/asterisk/chan_dahdi.conf` file::

    echocancel = 1


Apply the configuration
=======================

To apply the configuration, restart the services::

  wazo-service restart


Next step
=========

Now that you have loaded the correct module for your card you must:

#. check if you need to follow one of the :ref:`echo_can_specific_conf` sections below,
#. and continue with the next configuration step which is to :ref:`configure your card <card_configuration>` according to the operator links.


.. _echo_can_specific_conf:

Specific configuration
======================

This section describes some specific configuration. You should not follow them
unless you have a specific need.


Use the Hardware Echo-canceller for DTMF detection
--------------------------------------------------

If you have an hardware echo-canceller you *may* want to use it to detect the DTMF signal
(instead of asterisk).

#. Create the file :file:`/etc/modprobe.d/xivo-hwec-dtmf.conf`::

     touch /etc/modprobe.d/xivo-hwec-dtmf.conf

#. Fill it with the following lines replacing ``DAHDI_MODULE_NAME`` by the correct module name
   (``wcte13xp``, ``wct4xxp`` ...)::

     options DAHDI_MODULE_NAME vpmdtmfsupport=1

#. Then, restart the services::

     wazo-service restart