[asterisk-users] SIP - Automatic Redial on No Answer

[Olle E Johansson]

2 apr 2007 kl. 10.46 skrev Olivier:

> Hi,
>
> What is the best way to implement Automatic Redial on No Answer ?
>
> Looking at http://www.ietf.org/internet-drafts/draft-ietf-sipping- 
> service-examples-12.txt I can see how Automatic Redial on Busy  
> could (should) be done.
> How would you do it on No Answer ?
>
> Is there any event you should SUBSCRIBE to so that you're notified  
> that you're callee is available ?
> What if you ask to be notified of next call ending ?
>
> This is particularly useful when phones accept several calls : on  
> some of them, I couldn't find a way to force them to reply "486  
> BUSY" after a wait, when the callee is on call and couldn't  
> explicitly reject or accept the incoming call.
>
> The scenario is :
>
> A calls B which is already on call,
> B is notified another call is here but B don't either reject or  
> answer the incoming call
> A has no way to know if the call is not answered because B is not  
> there or too busy to reply
> Ideally, A would then ask for Automatic Redial on No Answer, with a  
> NOTIFY-SUBSCRIBE
> Later, when B is finishing a call (the one he was busy with or a  
> brand new one after returning to his desk), A is notified and  
> Automatic Redial can occur.
>
As always, there are many ways to handle this. If your phone supports  
SUBSCRIBE, Asterisk does it too.
In that case, it's up to the phone.

Otherwise, you could come up with a multiprotocol dialplan-based  
solution where you

- answer A's call and play a prompt for "busy" or "no reply" - like  
in Voicemail
- ask the user to press 1 to redial (if B is busy)
- have an app monitor B's connection over manager
- when B is done, place call to A, then connect to B
- lock B so no one else calls in between

The big issue here is the external app. Maybe someone can figure out  
a way to do it without it...

/Olle
---
* Olle E. Johansson - oej at edvina.net
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