The best way to find out if this works would be to call and see if the call is accepted and if you get something back from your AGI server and you can do this with automatically with Adhearsion!

What you will need is a wav file containing a DTMF sequence. You can create one with Adobe Audition for example (aka Cooledit before Adobe took over). The Trial version is enough to create the DTMF. Use a 300ms pause at least the other settings didn’t really work for me. Also don’t forget to set your Asterisk server to dtmfmod=inband.

I created a new adhearsion project and used the Simon game as start of and modified it to look like this:

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methods_for :dialplan do
  def check_call
    CheckCall.new(self).start
  end
end
 
class CheckCall
 
  def initialize(call)
    @call = call
    @number='12345'
  end
 
  def start
    collect_attempt
    verify_attempt
  end
 
  def collect_attempt
    @attempt = @call.input @number.length,
      :timeout => 10.seconds    
  end
 
  def verify_attempt
    if attempt_correct? 
		# do something here
    else
		# do something else
    end
  end
 
  def attempt_correct?
    @attempt == @number
  end
 
end

What this does is check if the called server sent the DTMF sequence 12345 and if not it would do something.

You cold for example use growl and/or prowl for notification or use some SMS service for notification like lcx.at (I know, shameless self promotion).

Also don’t forget to activate drb in your adhersion project, do this in startup.rb

config.enable_asterisk
config.asterisk.enable_ami :host => "localhost", :username => "amiuser", :password => "amipassowrd", :events => true
 
config.enable_drb :host => "0.0.0.0", :deny => "0.0.0.0", :allow => ["127.0.0.1", "213.123.118.123"]

Ok now all we need is the script that triggers the call. This could look like this:

require 'drb'
@adhearsion = DRbObject.new_with_uri "druby://localhost:9050"
result = @adhearsion.originate({ :channel   => "SIP/....", 
                                 :context   => "checkcall", 
                                 :exten 	=> '4000',
                                 :priority  => 1,
                                 :callerid  => "43123456789",
                                 :async => 'true',                                     
                                 :variable  => "call_launcher=true|sleep_time=3600" })

So, this is it. I know this isn’t really a copy & paste howto, some things are missing but I don’t want to repeat things that can be read in the adhearsion documentation.
Oh, what I forgot to mention, I use a separate server which runs Asterisk to do the checks, the checks are NOT done form the same server I am checking, but I think this should be obvious.
If you need a VPS with this Setup, or need someone to verify your VoIP Servers, feel free to contact me!

So, if you are in the same situation as I was and don’t have time to set up your own asterisk server and find some cheap VoIP routes to your destination, just contact me and I will help you