Asterisk dialplan - Prevent Hangup

Question

Consider the following scenario :

1. A is in call with B
2. B hangs up

Is there any way to redirect the A's channel to some other context so that the A's call is not disconnected and I can bridge another channel to A by using a php AGI script or by using the AMI to attach an event handler and then perform the redirect via AMI ?

The following is my desired behaviour:

1. A is in call with B, C is in a waiting list
2. B hangs up
3. A's call is not hung up and can use a DTMF to switch to C's call

I am using asterisk 13.

EDIT: The call is an incoming call or the call is made by writing a call file, without using the dial command

Answer 1

Yes, if you dial via Dial command with "g" option call will go dialplan and you will be able call other person

[Syntax]
Dial(Technology/Resource[&Technology2/Resource2[&...]][,timeout[,options[,URL]]])

[Arguments]
Technology/Resource
    Specification of the device(s) to dial.  These must be in the format
    of 'Technology/Resource', where <Technology> represents a particular
    channel driver, and <Resource> represents a resource available to that
    particular channel driver.
Technology2/Resource2
    Optional extra devices to dial in parallel
    If you need more then one enter them as Technology2/Resource2&Te
    chnology3/Resourse3&.....
timeout
    Specifies the number of seconds we attempt to dial the specified
    devices
    If not specified, this defaults to 136 years.
options
   .....
   g: Proceed with dialplan execution at the next priority in the current
       extension if the destination channel hangs up.

Answer 2

You can use option 'g' in dial command.Using this option,When the called party say B hangs up, continue to execute commands in the current context at the next priority.For details visit Asterisk Dial cmd options

Answer 3

It seems that you want to put the queue like feature. If yes then implement the queue and put the phone in auto answer mode. It may resolve your purpose. A will be act as an agent and B and C will dial the queue number and will wait for A in the queue.

Answer 4

The best way to do this is the following:

1. Accept the A call into a Stasis application
2. Using the bridges API, put the A call into a holding bridge
3. Accept the B call into a new Stasis application
4. Obtain the location of the bridge via a shared storage (Redis, Memcache, MySQL)

5. Using the bridges API, put the B call into the bridge

   When B call hangs up, A call is still in the bridge, waiting for the next call in line - this would be the best methodology to do this. As you are using Asterisk 13, ARI and Stasis are at your disposal.

   Take a look at http://www.phpari.org to get a feel of the idea - is't not as complicated as it sounds.