<sect1 id="configurations-ppp-device">
<title>The Modem Device</title>
<sect2 id="configurations-ppp-device-install">
<title>Installation</title>
<para>
Start with a minimal installation of &TCD;, bootup the
operating system, and login as root user. Later, install the
<quote>Dialup Networking Support</quote> group of packages
available in the <code>[base]</code> repository of &TCD;. The
installation of this group of packages is required both in
server and client computers. If you don't have this group of
packages installed in your computer, then you can do it as the
following command describes:
</para>
<screen>yum groupinstall "Dialup Networking Support"</screen>
<para>
The modem device installation consists on attacthing the modem
hardware both to the computer and the telephone line. 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 phone 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 phone
device to the modem's phone port, so you be able of realizing
phone calls when no data transmition take place, as well.
</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. For example, if you are
using an USB modem like that one we mentioned before, run the
following command:
</para>
<screen>sudo /sbin/lsusb</screen>
<para>
and you should get an output similar to 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.
</para>
<para>
At this point, your computer should be able of responding to
incoming calls but cannot realize outgoing calls, yet. To
administer the way incoming calls are attended in this
computer, read <xref linkend="configurations-ppp-server"
/>. On the other hand, to realize outgoing calls from this
computer, you need to specify the server information you want
to establish connection to, as described in <xref
linkend="configurations-ppp-modem-client" />.
</para>
</sect2>
<sect2 id="configurations-ppp-device-config">
<title>Configuration</title>
<para>
Once the modem hardware has been installed in the computer, it
is necessary to determine what device location the operating
system assigned to it, so you can instruct applications like
<application>chat</application> the correct device they will
to talk to. This configuration process has been greatly
simplified thanks to the <command>wvdialconf</command>
command, distributed with the <package>wvdial</package>
package.
</para>
<sect3 id="configurations-ppp-device-config-wvdial">
<title>The <command>wvdialconf</command> Command</title>
<para>
The <command>wvdialconf</command> automatically detects the
location the operating system assigned to your modem, its
maximum baud rate, a good initialization string for it, and
generates/updates the <command>wvdial</command> configuration
file (<filename>/etc/wvdial.conf</filename>) the
<command>wvdial</command> command needs to work. To set the
modem configuration through <command>wvdialconf</command>
command, run the command as follows:
</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>
<note>
<para>
It is possible to configure the same computer to act both as
server (i.e., to receive incoming calls from clients) and
client (i.e., to realize outgoing calls to servers). However,
be aware that only one of these connections can be established
at a time.
</para>
</note>
</sect3>
<sect3 id="configuration-ppp-device-config-scn">
<title>The <command>system-config-network</command> Command</title>
<para>
Another way to configure modems installed in your computer is
through the graphical interface provided by
<command>system-config-network</command> command. This
interface may result specially useful when you need to
configure your computer to establish Modem connections to
remote Internet Service Providers (ISPs). The interface
provided by <command>system-config-network</command> command
uses the same configuration file that
<command>wvdialconf</command> command does (e.g.,
<filename>/etc/wvdial.conf</filename>), however, there are
some differences in the way these commands create
configuration files that we need to be aware of.
</para>
<para>
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 it, any
configuration previously created by
<command>wvdailconf</command> command will be lost. On the
other hand, if you firstly generate the configuration file
using the interface provided by
<command>system-config-network</command> command and later run
the <command>wvdialconf</command> command over it, you will
end up having two similar configuration settings under
different definitions stored in the same configuration file.
</para>
<note>
<para>
The <command>wvdial</command> command doesn't understand the
configuration file produced by
<command>system-config-network</command> command, even both
<command>wvdialconf</command> and
<command>system-config-network</command> commands use the same
configuration syntax to create the configuration file.
</para>
</note>
<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 <code>[Modem0]</code> line,
while the <command>wvdialconf</command> command does the same
through the <code>[Dialer Defaults]</code> line. 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 <code>[Modem0]</code> 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>
<caution>
<para>
The interface provided by
<command>system-config-network</command> command doesn't
provide modem detection (as <command>wvdialconf</command>
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 issue, 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>
</sect3>
</sect2>
</sect1>