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\subsection{Introduction}

chan\_local is a pseudo-channel. Use of this channel simply loops calls back 
into the dialplan in a different context. Useful for recursive routing.

\subsection{Syntax}
\begin{verbatim}
 Local/extension@context[/n]
\end{verbatim}

Adding "/n" at the end of the string will make the Local channel not do a 
native transfer (the "n" stands for "n"o release) upon the remote end answering 
the line. This is an esoteric, but important feature if you expect the Local 
channel to handle calls exactly like a normal channel. If you do not have the 
"no release" feature set, then as soon as the destination (inside of the Local 
channel) answers the line, the variables and dial plan will revert back to that 
of the original call, and the Local channel will become a zombie and be removed 
from the active channels list. This is desirable in some circumstances, but can 
result in unexpected dialplan behavior if you are doing fancy things with 
variables in your call handling.

There is another option that can be used with local channels, which is the "j" 
option.  The "j" option must be used with the "n" option to make sure that the 
local channel does not get optimized out of the call.  This option will enable 
a jitterbuffer on the local channel.  The jitterbuffer will be used to de-jitter 
audio that it receives from the channel that called the local channel.  This is 
especially in the case of putting chan\_local in between an incoming SIP call 
and Asterisk applications, so that the incoming audio will be de-jittered.

\subsection{Purpose}

The Local channel construct can be used to establish dialing into any part of 
the dialplan.

Imagine you have a TE410P in your box. You want to do something for which you 
must use a Dial statement (for instance when dropping files in 
\path{/var/spool/outgoing}) but you do want to be able to use your dialplans 
least-cost-routes or other intelligent stuff. What you could do before we had 
chan\_local was create a cross-link between two ports of the TE410P and then 
Dial out one port and in the other. This way you could control where the call 
was going.

Of course, this was a nasty hack, and to make it more sensible, chan\_local was 
built.

The "Local" channel driver allows you to convert an arbitrary extension into a 
channel. It is used in a variety of places, including agents, etc.

This also allows us to hop to contexts like a GoSub routine; See examples below.

\subsection{Examples}

\begin{verbatim}
[inbound] ; here falls all incoming calls
exten => s,1,Answer
exten => s,2,Dial(local/200@internal,30,r)
exten => s,3,Playback(sorrynoanswer)
exten => s,4,Hangup

[internal] ; here where our phones falls for default
exten => 200,1,Dial(sip/blah)
exten => 200,102,VoiceMail(${EXTEN}@default)
  
exten => 201,1,Dial(zap/1)
exten => 201,102,VoiceMail(${EXTEN}@default)

exten => _0.,1,Dial(Zap/g1/${EXTEN:1}) ; outgoing calls with 0+number
\end{verbatim}

\subsection{Caveats}

If you use chan\_local from a call-file and you want to pass channel variables 
into your context, make sure you append the '/n', because otherwise 
chan\_local will 'optimize' itself out of the call-path, and the variables will 
get lost. i.e.

\begin{verbatim}
 Local/00531234567@pbx becomes Local/00531234567@pbx/n
\end{verbatim}