Set up Asterisk conference calling with MeetMe.

Asterisk phone

I made my first (2-way) conference call on Asterisk/Meetme just now. To enable MeetMe with Asterisk, you first need to edit your meetme.conf in /etc/asterisk/ , mine looks like this:

;
; Configuration file for MeetMe simple conference rooms for Asterisk of course.
;
; This configuration file is read every time you call app meetme()

[general]
audiobuffers=32    ; The number of 20ms audio buffers to be used
; when feeding audio frames from non-Zap channels
; into the conference; larger numbers will allow
; for the conference to ‘de-jitter’ audio that arrives
; at different timing than the conference’s timing
; source, but can also allow for latency in hearing
; the audio from the speaker. Minimum value is 2,
; maximum value is 32.
;
[rooms]
;
; Usage is conf => confno[,pin][,adminpin]
;
; Note that once a participant has called the conference, a change to the pin
; number done in this file will not take effect until there are no more users
; in the conference and it goes away.  When it is created again, it will have
; the new pin number.
;
conf => 1234

– apparently, it’s important to leave a blank line at the end of the file. All this does is define a conference room at 1234, with 32 x 20ms audio buffers (the default).

Next, you need to edit the extensions.conf (also in /etc/asterisk) to define how to get to your conference room – I added a line like this at the end, just after where my other users were defined:

exten => 1234,1,MeetMe(1234)

… so now, when Asterisk is restarted, it should enable the conference facility when ‘1234’ is dialled. It’s not so simple though.
MeetMe needs a reference clock to work properly, and it doesn’t have one by default. There’s a software clock in the package zaptel-source called ztdummy which needs compiling, but the current Ubuntu 9.04 source won’t compile; there’s a bug. Happily, this has been fixed – you need to add this Personal Package Archive to your list of sources in Synaptic, and install it’s key, fetch the packages zaptel and zaptel-source using Synaptic,  then compile it using the command:
sudo m-a a-i zaptel
… now when you restart your Asterisk and dial into 1234, you should get a voice recording telling you that you’re ‘the only person in this conference’.