<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 

        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

        Multi-Tech System, Inc. MT5634ZBA-USB MultiModemUSB (new

        firmware) device. If the modem you installed doesn't

        appear in this list, it is probably because such hardware is

        not supported by &TC;;, yet.

    </para>

    <para>

        At this point, everything is ready for you to install and

        configure the computer either as server (see 

        linkend="configurations-dialup-server" />) or client (see

        <xref linkend="configurations-dialup-client" />).

    </para>

</sect1>