251 lines
4.9 KiB
HTML
251 lines
4.9 KiB
HTML
<HTML
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><HEAD
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><TITLE
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>Configuring your modem</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.52"><LINK
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REL="HOME"
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TITLE="Linux PPP HOWTO"
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HREF="index.html"><LINK
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TITLE="Configuring your modem and serial port"
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HREF="modem.html"><LINK
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TITLE="Serial Port Names"
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TITLE="Note on Serial Flow Control"
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><A
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HREF="http://www.linuxports.com/howto/ppp"
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TARGET="_top"
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>Linux PPP HOWTO</A
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WIDTH="10%"
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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>Chapter 12. Configuring your modem and serial port</TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="x797.html"
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>Next</A
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></TD
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><H1
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CLASS="SECT1"
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><A
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NAME="AEN761"
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>12.3. Configuring your modem</A
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></H1
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><P
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>You will need to configure your modem correctly for PPP - to do this <I
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CLASS="EMPHASIS"
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>READ
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YOUR MODEM MANUAL</I
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>! Most modems come with a <I
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CLASS="EMPHASIS"
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>factory default setting</I
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>
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that selects the options required for PPP. The minimum configuration
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specifies:-
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<P
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></P
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><UL
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><LI
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><P
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>Hardware flow control (RTS/CTS) (<TT
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CLASS="LITERAL"
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>&</TT
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>K3 on many Hayes modems)</P
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></LI
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></UL
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> </P
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><P
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>Other settings (in standard Hayes commands) you should investigate are:
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<P
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></P
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><UL
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><LI
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><P
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>E1 Command/usr/src/linux-2.0.27/include/linux/serial.h Echo ON (required for chat to operate).</P
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></LI
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><LI
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><P
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>Q0 Report result codes (required for chat to operate).</P
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></LI
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><LI
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><P
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>S0=0 Auto Answer OFF (unless you want your modem to answer the phone).</P
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></LI
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><LI
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><P
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><TT
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CLASS="LITERAL"
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>&</TT
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>C1 Carrier Detect ON only after connect.</P
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></LI
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><LI
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><P
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><TT
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CLASS="LITERAL"
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>&</TT
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>S0 Data Set Ready (DSR) always ON.</P
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></LI
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><LI
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><P
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>(depends) Data Terminal Ready.</P
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></LI
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></UL
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> </P
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><P
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>There is a site offering modem setups for a growing variety of modems,
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makes and models at <A
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HREF="http://www.in.net/info/modems/index.html"
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TARGET="_top"
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>Modem setup information</A
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> which may assist you in this.</P
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><P
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>It is also worth while investigating how the modem's serial interface
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between your computer and modem operates. Most modern modems allow you
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to run the serial interface at a FIXED speed whilst allowing the
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telephone line interface to change its speed to the highest speed it and
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the remote modem can both handle.</P
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><P
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>This is known as split speed operation. If your modem supports this,
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lock the modem's serial interface to its highest available speed
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(usually 115,200 baud but maybe 38,400 baud for 14,400 baud modems).</P
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><P
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>Use your communications software (e.g. minicom or seyon) to find out
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about your modem configuration and set it to what is required for PPP.
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Many modems report their current settings in response to
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AT<TT
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CLASS="LITERAL"
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>&</TT
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>V, but you should consult your modem manual.</P
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><P
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>If you completely mess up the settings, you can return to sanity
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(usually) by issuing an AT<TT
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CLASS="LITERAL"
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>&</TT
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>F - return to factory settings.
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(For most modem modems I have encountered, the factory settings include
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all you need for PPP - but you should check).</P
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><P
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>Once you have worked out the modem setup string required, write it down.
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You now have a decision: you can store these settings in your modem
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non-volatile memory so they can be recalled by issuing the appropriate
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AT command, or you can pass the correct settings to your
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modem as part of the PPP dialing process.</P
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><P
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>If you only use your modem from Linux to call into your ISP or corporate
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server, the simplest set up will have you save your modem configuration
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in non-volatile RAM. </P
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><P
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>If on the other hand, you modem is used by other applications and
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operating systems, it is safest to pass this information to the modem as
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each call is made so that the modem is guaranteed to be in the correct
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state for the call. (This has the added advantage also of recording the modem
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setup string in case the modem looses the contents of its NV-RAM, which
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can indeed happen).</P
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></DIV
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>Prev</A
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>Home</A
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HREF="x797.html"
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>Next</A
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>Serial Port Names</TD
|
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="modem.html"
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>Up</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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>Note on Serial Flow Control</TD
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></TR
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></TABLE
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> |