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Comment: fixed a confusing sentence and a few typos


Pre-dial handlers allow you to execute a dialplan subroutine on a channel before a call is placed but after the application performing a dial action is invoked. This means that the handlers are executed after the creation of the caller/callee channels, but before any actions have been taken to actually dial the callee channels. You can execute a dialplan subroutine on the caller channel and on each callee channel dialleddialed.

There are two ways in which a pre-dial handler can be invoked:


  • As pre-dial handlers are implemented using Gosub subroutines, they must be terminated with a call to Return.
  • Taking actions in pre-dial handlers that would put the caller/callee channels into other applications will result in undefined behaviour. Pre-dial handlers should be short routines that do not impact the state that the dialling dialing application assumes the channel will be in.


Handlers For Dial or FollowMe, handlers are invoked using similar nomenclature as other options (such as M or U) in Dial or FollowMe ) that cause some portion of the dialplan to execute.


The examples illustrated below use the following channels:

  • SIP/foo is calls calling either SIP/bar, SIP/baz, or both
  • SIP/foo is the caller
  • SIP/bar is a callee
  • SIP/baz is another callee