<sect1 id="configurations-dialup-modem">

    <title>The Modem Hardware</title>

    <para>
        In order to establish a PPP link between two computers using
        the telephone line as medium for data transmission, you need
        to install (at least) one modem device in each computer.
    </para>

    <para>
        To install a modem device in computer you need to attach the
        modem hardware to the computer and later the telephone line to
        the modem hardware. To connect the modem to your computer, you
        need to connect the serial or USB cable that comes from the
        modem hardware to the appropriate input on your computer. To
        connect the modem to the telephone line system, you need to
        unplug the cable that connects your telephone device and plug
        it on the modem device, specifically in the port reserved for
        data transmission.  Later, using a similar cable, you could
        connect your telephone device to the modem's telephone port,
        so you can realize telephone calls when no data transmition
        take place.
    </para>

    <para>
        To be on the safe side, do all the installation with the
        computer turned off. Then, when everthing has been put in
        place, turn it on. Once the system is up, you can verify the
        modem hardware using either the <command>lsusb</command> or
        <command>lspci</command> commands. These commands need to be
        run with administrative privileges, so probably need to
        <command>sudo</command> them or login as <systemitem
        class="username">root</systemitem> user in order to execute
        thme. For example, assuming you are logged in as root user,
        and you are using an USB modem like that one we mentioned
        before, the output of <command>lsusb</command> command would
        look like the following:
    </para>

<screen>
Bus 003 Device 001: ID 0000:0000  
Bus 001 Device 001: ID 0000:0000  
Bus 001 Device 002: ID 058f:6366 Alcor Micro Corp. Multi Flash Reader
Bus 002 Device 001: ID 0000:0000  
Bus 005 Device 003: ID 06e0:f104 Multi-Tech Systems, Inc.
MT5634ZBA-USB MultiModemUSB (new firmware)
Bus 005 Device 001: ID 0000:0000  
Bus 005 Device 002: ID 046d:c018 Logitech, Inc. Optical Wheel Mouse
Bus 004 Device 001: ID 0000:0000 
</screen>

    <para>
        The relevant line here is that mentioning the existence of a
        <code>Multi-Tech System, Inc. MT5634ZBA-USB MultiModemUSB (new
        firmware)</code> device. If the modem you installed doesn't
        appear in this list, it is probably because such hardware is
        not supported by &TCD;, yet.
    </para>

    <para>
        At this point, everything is ready for you to install and
        configure the computer either as server (see <xref
        linkend="configurations-dialup-server" />) or client (see
        <xref linkend="configurations-dialup-client" />).
    </para>

</sect1>