<sect1 id="configurations-ppp-modem-config">

    <title>Configuring The Modem Device</title>

    <para>

        Once the modem hardware has been installed in the computer, it

        is necessary to determine what device inside the operating

        system it was assigned to, so applications like

        <command>pppd</command> and <command>chat</command> can talk

        to it.  This configuration process can be realized through the

        <command>wvdialconf</command> command distributed with the

        <package>wvdial</package> package or the

        <command>system-config-network</command> command. Once the 

    </para>

    <sect2 id="configurations-ppp-modem-config-wvdial">

    <title><command>wvdialconf</command></title>

    <para>

        The <command>wvdialconf</command> automatically detects your

        modem and generates/updates the <command>wvdial</command>

        configuration file (<filename>/etc/wvdial.conf</filename>)

        using the modem's maximum baud rate found in the

        auto-detection process, and a good initialization string for

        it, as well.  To set the modem configuration through

        <command>wvdialconf</command> command, run the following

        command:

    </para>

    <screen>sudo /usr/bin/wvdialconf /etc/wvdial.conf</screen>

    <para>

        This command will produce an output like the following:

    </para>

<screen>

Scanning your serial ports for a modem.

ttyS0<*1>: ATQ0 V1 E1 -- failed with 2400 baud, next try: 9600 baud

ttyS0<*1>: ATQ0 V1 E1 -- failed with 9600 baud, next try: 115200 baud

ttyS0<*1>: ATQ0 V1 E1 -- and failed too at 115200, giving up.

Port Scan<*1>: S1   S2   S3   

WvModem<*1>: Cannot get information for serial port.

ttyACM0<*1>: ATQ0 V1 E1 -- OK

ttyACM0<*1>: ATQ0 V1 E1 Z -- OK

ttyACM0<*1>: ATQ0 V1 E1 S0=0 -- OK

ttyACM0<*1>: ATQ0 V1 E1 S0=0 &C1 -- OK

ttyACM0<*1>: ATQ0 V1 E1 S0=0 &C1 &D2 -- OK

ttyACM0<*1>: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 -- OK

ttyACM0<*1>: Modem Identifier: ATI -- LT V.90 1.0 MT5634ZBA-USB

Data/Fax Modem (Dual Config) Version 5.18e

ttyACM0<*1>: Speed 4800: AT -- OK

ttyACM0<*1>: Speed 9600: AT -- OK

ttyACM0<*1>: Speed 19200: AT -- OK

ttyACM0<*1>: Speed 38400: AT -- OK

ttyACM0<*1>: Speed 57600: AT -- OK

ttyACM0<*1>: Speed 115200: AT -- OK

ttyACM0<*1>: Speed 230400: AT -- OK

ttyACM0<*1>: Speed 460800: AT -- OK

ttyACM0<*1>: Max speed is 460800; that should be safe.

ttyACM0<*1>: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 -- OK

Found an USB modem on /dev/ttyACM0.

Modem configuration written to /etc/wvdial.conf.

ttyACM0<Info>: Speed 460800; init "ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0"

</screen>

    <para>

        and a <command>wvdial</command> configuration file like the

        following:

    </para>

<screen>

[Dialer Defaults]

Modem = /dev/ttyACM0

Baud = 460800

Init1 = ATZ

Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0

ISDN = 0

Modem Type = USB Modem

; Phone = <Target Phone Number>

; Username = <Your Login Name>

; Password = <Your Password>

</screen>

    <para>

        At this point, the computer should be ready to attend incoming

        calls.  

    </para>

    <para>

        When an incoming call arrives to the server they are attended

        by the <application>pppd</application> deamon. To administer

        the way such incoming calls are attended (e.g., forcing user

        authentication, restricting the phone numbers the calls can be

        initiated from, etc.), you need to set the

        <application>pppd</application> deamon configuration to fit

        your needs.  To know more about how to configure the

        <application>pppd</application> deamon and the options it

        provides, read its man page (e.g., <command>man

        pppd</command>).

    </para>

    <para>

        On the other hand, when you are configuring a computer to act

        as client (i.e., you are calling out an ISP to establish

        connection to it), you need to realize a few more tunning

        steps on <filename>/etc/wvdial.conf</filename> to set the

        information related of that Internet Service Provider (ISP)

        you want to get connected to (e.g., uncommenting the

        Phone, Username and

        Password lines above to set the appropiate values

        there). 

    </para>

    <para>

        Once you've specified the ISP information, run the following

        command to stablish connection: 

    </para>

    <screen>sudo /usr/bin/wvdial</screen>

    <note>

    <para>

        Both <command>wvdial</command> and

        <command>wvdialconf</command> commands must be run with

        administrative privilages because its configuration file

        (<filename>/etc/wvdial.conf</filename>) is readable by the

        <systemitem class="username">root</systemitem> user only.

    </para>

    </note>

    </sect2>

    <sect2 id="configuration-ppp-modem-config-scn">

    <title><command>system-config-network</command></title>

    <para>

        In addition to the configuration process described so far, you

        can manage modem configurations through the

        <command>system-config-network</command> command. This command

        provides a graphical interface (administrative privileges

        required) which let you configure several ISP and alternate

        the one you connect to. This command has been already

        documented in the <citetitle>Deployment Guide</citetitle>

        availabe in the <package>Deployment_Guide</package> and we

        won't duplicate that information here. However, there are some

        differences between the output produced by

        <command>system-config-network</command> and

        <command>wvdialconf</command> commads you need to be aware of.

    </para>

    <para>

        The first thing to know is that both

        <command>system-config-network</command> and

        <command>wvdialconf</command> commands write configurations to

        the <filename>/etc/wvdial.conf</filename> file, but the

        interface provided by <command>system-config-network</command>

        command doesn't detect the configuration intially created by

        <command>wvdialconf</command> command. In fact, if you set a

        new (modem) hardware configuration through the interface

        provided by the <command>system-config-network</command>

        command, any configuraion previously created by

        <command>wvdailconf</command> will be lost.

    </para>

    <caution>

    <para>

        The interface provided by

        <command>system-config-network</command> command doesn't

        provide modem device detection (as

        <command>wvdialconf</command> would do) and uses the

        <filename>/dev/modem</filename> as default location. This

        location doesn't exists by default, so whatever configuration

        you set from it will not work. To solve this, chose one of the

        following workarounds: 

    </para>

    <itemizedlist>

    <listitem>

    <para>

        Replace the <filename>/dev/modem</filename> location by that

        one <command>wvdialconf</command> found when the interface

        provided by <command>system-config-network</command> ask you

        to enter the modem device.

    </para>

    </listitem>

    <listitem>

    <para>

        Create <filename>/dev/modem</filename> location as a symbolic

        link to that location found by <command>wvdialconf</command>

        command. For example:

        <screen>sudo /bin/ln -s /dev/ttyACM0 /dev/modem</screen>

    </para>

    </listitem>

    </itemizedlist>

    </caution>

    <para>

        Inside the <filename>/etc/wvdial.conf</filename> configuration

        file, the interface provided by

        <command>system-config-network</command> identifies default

        modem configurations through the line [Modem0],

        while the <command>wvdialconf</command> command does the same

        through the line [Dialer Defauls]. Something

        interesting about the configuration file created by

        <command>system-config-network</command> is that it is

        possible to create several ISP configurations that reuse

        default settings in the [Modem0] section. For

        example, consider the following example:

    </para>

<screen>

[Modem0]

Modem = /dev/ttyACM0

Baud = 460800

SetVolume = 2

Dial Command = ATDT

Init1 = ATZ

Init3 = ATM1L2

FlowControl = CRTSCTS

[Dialer Vispa_Internet]

Username = signup

Password = rebel

Phone = 08453080125

Stupid Mode = 1

Init1 = ATZ

Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0

Inherits = Modem0

</screen>

    </sect2>

</sect1>