[asterisk-users] How to catch isdn progress message

[rp]

> Message: 12
> Date: Thu, 10 Sep 2009 13:11:27 +0200
> From: "Jay R. Worthington" <jayrworthington at gmail.com>
> Subject: Re: [asterisk-users] How to catch isdn progress message
> To: asterisk-users at lists.digium.com
> Message-ID:
> 	<710bae00909100411u450d406ao1655c200e4d84603 at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
>> We have to record and decode isdn PROGRESS message and when  
>> particular
>> message is found call should be hang up and dialplan should continue.
>
> Let me guess: You want to build yet another dialer that calls some  
> numbers
> to flood 'em with ads...?
>
> Good luck getting help here.
>
> Jay

And let me politely tell you: it is not true.

Our use case is as follows:

We need to implement our own voicemail for mobile phones instead of
carrier's one.

Mobile phones are in VPN connected through E1 line to our asterisk  
server.
Call forwarding on mobile phones is set up in such way that instead of
carrier's voicemail box they are forwarding calls to number disallowed  
by VPN
calling policy.

When this happens, carrier sends us a PROGRESS message.

So basically when we receive particular PROGRESS, we know, that
call should go to carrier's voicemail, but due way phones are set up it
cannot reach it.

Continuing in dialplan at this moment, or being able to hangup a call  
somehow,
would allow us to present our own voicemail to calling party.

For clarity I will restate our ideas of how to solve this situation  
again:

1) add special progress extension to dialplan so we can start
something like AMD (app_amd.c) as progress arrives to decode the
message and than eventually call HangUp.

2) change app_dial.c to return to dialplan when progress arrives and
than either call HangUp or something like WaitForConnectedCall.

We'll be glad for some advice which method is better/where's the best  
place
to change asterisk to allow for this functionality.

Thanks for your help
Roman