voice_compression_configuration.rst

Voice Compression Card configuration

Verifications

Verify that the wctc4xxp module is uncommented in /etc/dahdi/modules.

If it wasn't, do again the step load_dahdi_modules.

Configure

To configure the card you have to:

1. Install the card firmware:

   xivo-fetchfw install digium-tc400m

2. Comment out the following line in /etc/asterisk/modules.conf:

   noload = codec_dahdi.so

3. Restart asterisk:

   service asterisk restart

Next step

Now that you have configured your Voice Compression card:

1. you must check if you need to follow one of the vc_card_specific_conf sections below,
2. then, if you have another type of card to configure, you can go back to the configure your card <card_configuration> section.

Specific configuration

Select the transcoding mode

The Digium TC400 card can be used to transcode:

• 120 G.729a channels,
• 92 G.723.1 channels,
• or 92 G.729a/G.723.1 channels.

Depending on the codec you want to transcode, you can modify the mode parameter which can take the following value:

• mode = mixed : this the default value which activates transcoding for 92 channels in G.729a or G.723.1 (5.3 Kbit and 6.3 Kbit)
• mode = g729 : this option activates transcoding for 120 channels in G.729a
• mode = g723 : this option activates transcoding for 92 channels in G.723.1 (5.3 Kbit et 6.3 Kbit)

1. Create the file /etc/modprobe.d/xivo-transcode.conf:

   touch /etc/modprobe.d/xivo-transcode.conf

2. And insert the following lines:

   options wctc4xxp mode=g729

3. Apply the configuration by restarting the services:

   wazo-service restart

4. Verify that the card is correctly seen by asterisk with the transcoder show CLI command
   • this command should show the encoders/decoders registered by the TC400 card:

   *CLI> transcoder show 0/0 encoders/decoders of 120 channels are in use.