| <sect1 id="connectivity-ppp-modem"> |
| |
| <title>The Modem Device</title> |
| |
| <para> |
| In order to establish a PPP link between two computers using |
| the telephone line as medium for data transmission, you will |
| need to install and configure a modem device in each computer |
| you plan to connect. On the other hand, if you're planning to |
| use PPP to connect the same computer to different networks |
| simultaneously (e.g., to build a proxy between them), you will |
| need to install and configure one modem device for each |
| different network you plan to establish such simultaneous |
| connection in the same computer. |
| </para> |
| |
| <sect2 id="connectivity-ppp-modem-install"> |
| <title>Installing Modem Devices</title> |
| <para> |
| To install a modem device in the computer, you need to attach |
| the modem hardware to the computer and later the telephone |
| line to the modem hardware. To attach the modem hardware 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 (whether serial or USB). To connect the modem |
| hardware to the telephone line, 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 through modem's data port. |
| </para> |
| |
| <para> |
| To be on the safe side, do everything related to hardware |
| installation with the computer turned off. Then, when |
| everthing has been put in place, turn the computer on. Once |
| the operating system is up and running, you can verify the |
| modem hardware using either the <command>lsusb</command> or |
| <command>lspci</command> commands, based on whether you |
| attached the modem device to an USB or serial port, |
| respectivly. These commands need to be run with |
| administrative privileges, thus, you probably need to do |
| <command>sudo</command> on them or login as <systemitem |
| class="username">root</systemitem> user in order to execute |
| them. For example, assuming you logged in as <systemitem |
| class="username">root</systemitem> user and you installed an |
| USB modem hardware as mentioned before, the output of |
| <command>lsusb</command> command would be similar to that |
| 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 in this output is that one mentioning the |
| existence of your modem. For example, <code>Multi-Tech System, |
| Inc. MT5634ZBA-USB MultimodemUSB (new |
| firmware</code>)<footnote> |
| <para> |
| I want to thank my friend Brians Suarez Alonso for |
| bringing this modem hardware to me and for his paitient, |
| resisting my repetitive calls at night to realize |
| connection tests. |
| </para> |
| </footnote>. This line confirms that your modem hardware is |
| supported by &TCD; and it is possible to transmit data through |
| it. Otherwise, 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> |
| Once you have confirmed the modem hardware has been installed |
| in the computer (either client or server), you need to |
| determine the device name the operating system assigned to it. |
| This information is required by programs like |
| <application>mgetty</application> and |
| <application>wvdial</application>, so they can know what |
| device to talk to. Assuming you've connected your modem |
| device through an USB port, the operating system will assign |
| the the <filename>/dev/ttyACM0</filename> device file to talk |
| to it. On the other hand, assuming you've connected your |
| modem device through a serial port, the operating system will |
| use the <filename>/dev/ttyS0</filename> device file to talk to |
| it. To be absolutly sure about what device name the operating |
| system assigned to your modem hardware, you can use the |
| <command>lshal</command> command from <package>hal</package> |
| package. |
| </para> |
| </sect2> |
| |
| <sect2 id="connectivity-ppp-modem-config"> |
| <title>Configuring Modem Devices</title> |
| |
| <para> |
| Inside &TCD;, modem devices can be configured using the |
| <command>system-config-network</command> tool. This tool is a |
| manages modem configuration files under the |
| <filename>/etc/sysconfig/network-scripts</filename> and |
| <filename>/etc/wvdial.conf</filename>. Inside |
| <filename>/etc/sysconfig/network-scripts</filename>, modem |
| configuration files can take different file names. To identify |
| them you need to open the file and checking the value set on |
| <varname>DEVICE</varname> variable. This variable can take |
| values like <code>ppp0</code> for the first modem device, |
| <code>ppp1</code> for the second modem device, and so on for |
| other modem devices. |
| </para> |
| |
| <para> |
| The configuration files of modem devices may vary based on |
| whether the computer is acting as server, client or both. |
| When you configure the modem device on the server computer, |
| you should take care of specifying both the IP address |
| (IPADDR) and the network mask (NETMASK) inside the |
| configuration file. Otherwise, the established connection |
| might end up having the wrong IP information you need to |
| transfer data correctly through it, assuming the other end |
| isn't configured to specify it. When you configure the modem |
| device on the server computer, there is no need for you to set |
| any configuration related to wvdial, unless you be thinking to |
| make your server computer to act as a client of another server |
| computer. In fact, in the server computer, you can create the |
| modem configuration file by yourself based on the information |
| provided at |
| <filename>/usr/share/doc/initscripts-*/sysconfig.txt |
| </filename> |
| </para> |
| |
| <para> |
| When you configure the modem device on the client computer, |
| you don't need to take care of specifying either the IP |
| address or network mask because the server computer will |
| assign them for you. The assignment of client computer IP |
| address is configured by <application>ppp</application> daemon |
| when it is executed by <application>mgetty</application> after |
| an incoming call has arrived to modem's port. |
| </para> |
| |
| <example id="connectivity-ppp-modem-config.fig-1"> |
| <title>Modem configuration file</title> |
| <screenshot> |
| <screeninfo>Modem configuration file</screeninfo> |
| <mediaobject> |
| <textobject> |
| <screen> |
| # Please read /usr/share/doc/initscripts-*/sysconfig.txt |
| # for the documentation of these parameters. |
| TYPE=modem |
| DEVICE=ppp0 |
| BOOTPROTO=none |
| ONBOOT=no |
| USERCTL=yes |
| PEERDNS=yes |
| AC=off |
| BSDCOMP=off |
| VJCCOMP=off |
| CCP=off |
| PC=off |
| VJ=off |
| LINESPEED=115200 |
| MODEMPORT=/dev/ttyACM0 |
| PROVIDER=ProviderName |
| DEFROUTE=yes |
| PERSIST=no |
| PAPNAME=faith |
| WVDIALSECT=ProviderName |
| MODEMNAME=Modem0 |
| DEMAND=no |
| IPV6INIT=no |
| IDLETIMEOUT=600 |
| NETMASK=255.255.255.0 |
| IPADDR=192.168.1.1 |
| </screen> |
| </textobject> |
| </mediaobject> |
| </screenshot> |
| </example> |
| |
| </sect2> |
| |
| </sect1> |