Index: vm1chp4-channelconfig.xml
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RCS file: /cvsroot/asterisk/docs/volume-one/vm1chp4-channelconfig.xml,v
retrieving revision 1.2
diff -r1.2 vm1chp4-channelconfig.xml
2a3,21
> 			<sectl>
> 			<title>Introduction to channels</title>
> 			<para>
> 			Channels are how an Asterisk system connects calls together.  They can be
> 			thought of like the wires used by old phone operators that hooked calls
> 			together.  The dialplan (Chapter 5) links these channels together and routes
> 			calls through them.  As all forms of calls create a channel of some sort,
> 			they play a vital role in developing your Asterisk installation.
> 			</para>
> 			<para>
> 			Channels come in all kinds of different formats from analog phone lines
> 			from your telephone company (FXO, FXS, PRI, BRI) to completely IP 
> 			(SIP, IAX, etc).  Asterisk transforms all of these channels into a kind of
> 			pipe for your call to flow through, and the pipes are connected together.
> 			It is important to remember that even though channels may vary in terms of
> 			technology and delivery, they are all just a channels, and channels can be
> 			connected to make a call.
> 			</para>
> 			</sectl>
6,7c25,90
< 			FXS in Dialplans == Zap/1
< 			FXO in Dialplans == Zap/2
---
> 			Foreign eXchange Station (FXS) channels are what your phone company provides
> 			to the wall of most homes or small businesses.  It is the traditional flat
> 			analog telephone line.  Since they provide dialtone, Asterisk can use an FXS
> 			channel to hook a basic analog phone set to the system to use for making and
> 			recieving calls.
> 			</para>
> 			<para>
> 			If you have a Digium card that can provide an FXS channel,
> 			like the TDM400P,  it can be configured like:
> 			<informalexample>
> 			In the zapata.conf we set up the channel:
> 			<programlisting>
> 			language=en
> 			context=default
> 			switchtype=national
> 			signalling=fxo_ls ; This is the signaling we're recieving not the one we're
> 			                  ; providing.  ie. We get are providing an FXS signal so we
> 					  ; are recieving an FXO signal.
> 			channel => 1
> 			</programlisting>
> 			</informalexample>
> 			</para>
> 			<para>
> 			This does not of course contain all of the options but it sets up a simple
> 			FXS channel.  It's important to remember that the signalling is always the
> 			signal you are recieving from the connected device, not the signal you are
> 			providing.  The name of the device type (FXS) is the type of signal you are
> 			providing.  This is confusing to some people, so it's defintely something to
> 			look out for.
> 			</para>
> 			<para>
> 			The main difference in the settings that are provided above when configuring
> 			an FXO channel instead of an FXS channel is signalling.  Of course an FXO
> 			channel will get plugged into something that provides and FXS channel (like
> 			the phone company).
> 			<informalexample>
> 			In the zapata.conf we set up the channel:
> 			<programlisting>
> 			language=en
> 			context=default
> 			switchtype=national
> 			signalling=fxo_ls ; This is the signaling we're recieving not the one we're
> 			                  ; providing.  ie. We get are providing an FXS signal so we
> 					  ; are recieving an FXO signal.
> 			channel => 1
> 
> 			signalling=fxs_ls
> 			channel => 2
> 			</programlisting>
> 			</para>
> 			<para>
> 			In the first example we listed channel 1 as an FXS channel.  To create an FXO
> 			channel on the same TDM400P card, we list all the settings for the channel
> 			and then define the channel number.  Instead of only having signalling be
> 			fxo_ls though we want the signalling to be fxs_ls.  Because the other
> 			settings haven't been changed (signalling=fxs_ls replaces the previous value
> 			of signalling), they stay the same.  Which means that while channel 1 takes
> 			on the values language=en, context=default, switchtype=national, and 
> 			signalling=fxo_ls; channel takes on the values language=en, context=default,
> 			switchtype=national, and signalling=fxs_ls.
> 			</para>
> 			<para>
> 			We now having a working example of a zapata.conf with an FXS channel (1) and
> 			an FXO channel (2) that we can use.  Channel 2 can be hooked to an analog
> 			phone jack like the one provided by a phone company and Channel 1 can be
> 			hooked directly to a standard analog telephone.