We will begin by renaming the confbridge.conf file to confbridge.conf.sample to use as a reference file. To do this use the command:

sudo mv /etc/asterisk/confbridge.conf /etc/asterisk/confbridge.conf.sample

Now create a new file to edit using the command:

sudo nano /etc/asterisk/confbridge.conf

We will look at adding 4 different contexts within the confbridge.conf file. Three of the contexts are required, [general], [default_user], and [default_bridge]. We will also add a context that can be used to control audio called [sample_user_menu].

The first context is [general]. There are no options currently available for this section. It is reserved for future use. So add the following information to the confbridge.conf file:

[general]

The next context we will create is for the default user. If no specific user is setup in the dialplan this context will be used. We will define the type of context as a user. If we want a user to hear music in the conference room when no one else is in the room we can set the music_on_hold_when_empty option. Also if we want to define what music is played we can use the music_on_hold_class option to select a moh class. To improve audio performance and remove the buildup of background noice it is recommend that we allow Asterisk to drop what it deems as silence from a call. This can be done with the dsp_drop_silence option. A pin number can also be set to authenticate participants. Append the following information in the confbridge.conf file:

[default_user]
type=user
music_on_hold_when_empty=yes
music_on_hold_class=default
dsp_drop_silence=yes
pin=1234

In the next context we will create a context that can be used to setup the bridge between callers. The [default_bridge] context is used by default if no specific bridge context is select from the dialplan. Conference calls can be recorded using the record_conference option. Append the following information in the confbridge.conf file:

[default_bridge]
type=bridge
record_conference=yes

In the default configuration of the confbridge.conf file there is a user menu that can be used to give the caller various options. Append the [sample_user_menu] listed below to the confbridge.conf file.

[sample_user_menu]
type=menu
*=playback_and_continue(conf-usermenu)
*1=toggle_mute
1=toggle_mute
*4=decrease_listening_volume
4=decrease_listening_volume
*6=increase_listening_volume
6=increase_listening_volume
*7=decrease_talking_volume
7=decrease_talking_volume
*8=leave_conference
8=leave_conference
*9=increase_talking_volume
9=increase_talking_volume