<para>
	The voicemail system provides <application>ser</application>
	with voice announcement and recording capabilities. Voice
	messages may then be mailed to the called user. The system
	relies on <application>ser</application> for implementating
	the <acronym>SIP</acronym> stack and communicate with it
	throught <acronym>FIFO</acronym>. It implements the dialog and media
	handling as described in RFC 3264 (An Offer/Answer Model with
	the Session Description Protocol) and RFC 1889 (Real time
	transport protocol) to realize its goal.

</para>
<section>
<title>Advantages</title>
	<para>
            Anyone deploying <application>ser</application> and
	    <acronym>VoIP</acronym> should profit from this 'ready-to-run'
	    application. It plugs into <application>ser</application> as
	    easy as configuring the database location, announce file path
	    and SMTP server address. 
	</para>
	<para>
	    Further,
	    <application>voicemail</application>
	    integrates the most popular free codecs
	    (G.711ulaw, G.711alaw and GSM 06.10) and
	    its own SMTP client, which means that you
	    don't need to install anything else as
	    <application>ser</application> and
	    <application>voicemail</application>. 
	</para>
	<para>
	    If you want your voicemail system to support
	    other codecs, a simple plugin system with
	    SDK alows you to integrate them fast and
	    simply (see the basis plugins for examples). 
	</para>
</section>
<section>
<title>Technical limitations</title>
	<para>
	    The sound conversion engine doesn't
	    support yet resampling. It means that
	    input and ouput files have to be
	    compatible with the sampling rate of the
	    codec. All codecs included with the
	    distribution work at 8kHz, which means
	    that all the input and output files MUST
	    be sampled at the rate of 8kHz.
	</para>
	<para>
	    At the moment, voicemail only support the
	    Microsoft Wav file format with PCM 16 bit,
	    Mu-law and A-law 8 bit encoding.
	</para>
</section>


<section>
<title>Compilation and installation</title>
	<para>
	    First, you need to compile Ser with voicemail
	    support. Thatfor, you must edit Ser's
	    Makefile.defs file and uncomment the line with
	    '-DVOICE_MAIL' and '-D_TOTAG'.
	</para>
	<para>
	    Then do 'make all' in Ser's root directory.
	</para>
	<para>
	    Configure Ser to fit your needs. You can
	    report to voicemail example config file to
	    know what your configuration file should
	    include. Note that voicemail
	    only needs to know the user database location
	    in order to work. Report to the README file in
	    the vm module directory for description of the
	    functions and variable that are used by
	    voicemail and how they work.
	</para>
	<para>
	    Finally, compile the voicemail application:
	</para>
	<para>
	    <programlisting>
		[~/voicemail]$ cd ortp-0.5.0
		[~/voicemail/ortp-0.5.0]$ ./configure
		[~/voicemail/ortp-0.5.0]$ make all
		[~/voicemail/ortp-0.5.0]$ cd ..
		[~/voicemail]$ cd plug-in/gsm/gsm-????
		[~/voicemail/plug-in/gsm/gsm-????]$ make all
		[~/voicemail/plug-in/gsm/gsm-????]$ cd ../..
		[~/voicemail]$ make all
	    </programlisting>
	</para>
	<para>
		You can then start voicemail with following
		command <command>ans_machine</command> and
		look if the default fit your needs. If not,
		type <command>ans_machine -h</command> to see
		how to change the default parameters.
	</para>
	<para>
		If <application>ans_machine</application> is
		not started or can't be joined while
		<application>ser</application> tries to
		communicate with it, the caller will become
		a '500 internal server error' with a comment
		saying what the trouble is.
	</para>
	<example>
                <title>Example ser Config File</title>
		<programlisting>
&voicemailcfg;
		</programlisting>
	</example>
</section>
<section>
<title>Availabilty, report bugs, contact the author</title>
<para>
        Ser's Voicemail is hosted at
	<ulink
	url="http://developer.berlios.de/projects/sems">http://developer.berlios.de/projects/sems</ulink>.
	A snapshot may be downloaded directly from the CVS tree. A
	pre-configured version of <application>ser</application>
	including <application>voicemail</application> will be soon
	available (starting from version 0.8.11). 
</para>
<para>
        Bugs can be directly reported at the voicemail's project page. If you
        want to contact the author, use the contact email at the
        project's web page.
</para>
</section>