The sounds that people expect from the telephone network vary in different parts of the world. Different countries or regions present different sounds for events such as dialtone, busy signal, ringback, congestion, and so forth.

The indications.conf file defines the parameters for the various sounds that a telephone system might be expected to produce, and allows you to customize them. In the early days of Asterisk this file only contained sounds for a limited number of countries, but it is now quite comprehensive.

To assign the tones common for your region to channels, you can simply assign the tonezone using the CHANNEL() function, and that tonezone will apply for the duration of the call (unless changed later):

Set(CHANNEL(tonezone)=[yourcountry]) ; i.e., uk, de, etc.

However, since signaling from a call could come from various places (from the carrier, from Asterisk, or even from the set itself), you should note that simply setting the tonezone in your dialplan does not guarantee that those tones will be presented in all situations.

While Asterisk will run without an indications.conf file, it is strongly recommended that you include one: copy the sample over with sudo cp ~/src/asterisk-complete/1.8/configs/indications.conf.sample, modify the country parameter in the [general] section to match your region, and restart Asterisk.

If your system supports multiple countries (for example, if you have a centralized Asterisk system that has users from different regions), you may not be able to simply define the default country. In this case, you have a couple of options:

  1. Define the country in the channel definition file for the user.

  2. Define the country in the dialplan using the CHANNEL(tonezone) function.

For more information about using Asterisk in different countries, see Chapter 9, Internationalization.