The indications.conf file is used to tell Asterisk how to generate the various telephone sounds common in different parts of the world; a dial tone in England sounds very different from a dial tone in Canada, but your Asterisk system will be pleased to make the sounds you want to hear. This file consists of a list of sounds a telephone system might need to produce (dial tone, busy signals, and so forth), followed by the frequencies used to generate those sounds.

By default (and without an indications.conf file), Asterisk will use the tones common in North America. You can change the default country for your system by specifying the two-letter country code in the [general] section. Supported country codes are listed in the indications.conf.sample file located in /usr/src/asterisk/configs. If you have the required information, your country can easily be added. Here’s what the configuration for North America looks like:

[general]
country=us
;
[us]
description = United States / North America
ringcadance = 2000,4000
dial = 350+440
busy = 480+620/500,0/500
ring = 440+480/2000,0/4000
congestion = 480+620/250,0/250
callwaiting = 440/300,0/10000
dialrecall = !350+440/100,!0/100,!350+440/100,!0/100,!350+440/100,!0/100,350+440
record = 1400/500,0/15000
info = !950/330,!1400/330,!1800/330,0