1 files changed, 74 insertions, 0 deletions
diff --git a/doc/extensions.tex b/doc/extensions.tex
new file mode 100644
index 000000000..28a49f092
--- /dev/null
+++ b/doc/extensions.tex
@@ -0,0 +1,74 @@
+\subsubsection{The Asterisk dialplan}
+
+The Asterisk dialplan is divided into contexts. A context is simply a group
+of extensions. For each "line" that should be able to be called, an extension
+must be added to a context. Then, you configure the calling "line" to have
+access to this context.
+
+If you change the dialplan, you can use the Asterisk CLI command
+"extensions reload" to load the new dialplan without disrupting
+service in your PBX.
+
+Extensions are routed according to priority and may be based on any set
+of characters (a-z), digits, \#, and *. Please note that when matching a
+pattern, "N", "X", and "Z" are interpreted as classes of digits.
+
+For each extension, several actions may be listed and must be given a unique
+priority. When each action completes, the call continues at the next priority
+(except for some modules which use explicitly GOTO's). 
+
+When each action completes, it generally moves to the next priority (except for
+some modules which use explicitly GOTO's. 
+
+Extensions frequently have data they pass to the executing application
+(most frequently a string).  You can see the available dialplan applications
+by entering the "show applications" command in the CLI.
+
+In this version of Asterisk, dialplan functions are added. These can
+be used as arguments to any application. For a list of the installed
+functions in your Asterisk, use the "show functions" command.
+
+\subsubsection{Example dialplan}
+
+The example dial plan, in the configs/extensions.conf.sample file
+is installed as extensions.conf if you run "make samples" after
+installation of Asterisk. This file includes many more instructions
+and examples than this file, so it's worthwhile to read it.
+	
+\subsubsection{Special extensions}
+
+There are some extensions with important meanings:
+
+\begin{itemize}
+  \item s	
+  \begin{itemize}
+    \item What to do when an extension context is entered (unless
+          overridden by the low level channel interface)
+          This is used in macros, and some special cases. 
+          "s" is not a generic catch-all wildcard extension.
+  \end{itemize}
+  \item i
+  \begin{itemize}
+    \item What to do if an invalid extension is entered
+  \end{itemize}
+  \item h
+  \begin{itemize}
+    \item The hangup extension, executed at hangup
+  \end{itemize}
+  \item t
+  \begin{itemize}
+    \item What to do if nothing is entered in the requisite amount
+          of time.
+  \end{itemize}
+  \item T
+  \begin{itemize}
+    \item This is the extension that is executed when the 'absolute'
+          timeout is reached.  See "show function TIMEOUT" for more
+          information on setting timeouts.	
+  \end{itemize}
+\end{itemize}
+
+And finally, the extension context "default" is used when either a) an 
+extension context is deleted while an extension is in use, or b) a specific
+starting extension handler has not been defined (unless overridden by the
+low level channel interface).