mirror of https://github.com/tLDP/LDP
111 lines
4.7 KiB
Plaintext
111 lines
4.7 KiB
Plaintext
<appendix id="X-087-2-appendix.cables"><title>Useful Cable Configurations</title>
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<para>
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If you wish to connect two computers together and you don't have an Ethernet
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network, you will need either a serial null modem cable, or a PLIP parallel
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cable.
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</para>
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<para>
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These cables can be bought off the shelf, but are much cheaper and fairly
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simple to make yourself.
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</para>
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<sect1 id="X-087-2-cable.plip"><title>A PLIP Parallel Cable</title>
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<para>
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<indexterm><primary>PLIP (Parallel Line IP) protocol</primary><secondary>null printer cable for</secondary></indexterm>
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To make a parallel cable to use for PLIP, you will need two 25-pin
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connectors (called DB-25) and a cable with at least eleven conductors.
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The cable must not be any longer than 15 meters (50 feet). The cable may or may
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not have a shield, but if you are building a long cable, it is probably
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a good idea to have one.
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</para>
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<para>
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If you look at the connector, you should be able to read tiny numbers
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at the base of each pin—from 1 for the pin at the top left (if you hold
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the broader side up) to 25 for the pin at the bottom right. For the null
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printer cable, you have to connect the following pins of both connectors
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with each other, as shown in <xref linkend="X-087-2-cable.plip.diagram">.
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</para>
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<para>
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All remaining pins remain unconnected. If the cable is shielded, the
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shield should be connected to the DB-25's metallic shell on just
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<emphasis>one</emphasis> end.
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</para>
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</sect1>
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<sect1 id="X-087-2-cable.serial"><title>A Serial NULL Modem Cable</title>
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<para>
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<indexterm><primary>SLIP (Serial Line IP) protocol</primary><secondary>null modem cable for</secondary></indexterm>
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<indexterm><primary>PPP (Point-to-Point Protocol)</primary><secondary>null modem cable for</secondary></indexterm>
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A serial null modem cable will work for both SLIP and PPP. Again, you
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will need two DB-25 connectors. This time your cable requires only
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eight conductors.
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</para>
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<para>
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You may have seen other NULL modem cable designs, but this one allows you
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to use hardware flow control—which is far superior to XON/XOFF
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flow control—or none at all. The conductor configuration is
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shown in <xref linkend="X-087-2-cable.nullmodem.diagram">:
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</para>
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<para>
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Again, if you have a shield, you should connect it to the first pin at one
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end only.
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</para>
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<figure id="X-087-2-cable.plip.diagram">
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<title>Parallel PLIP cable</title>
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<!-- <graphic fileref="lag2_ab01.jpg"></graphic> -->
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<!-- 2016-01-28; MAB, TLDP -->
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<mediaobject>
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<imageobject>
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<imagedata fileref="images/lag2_ab01.jpg" format="jpg">
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</imageobject>
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<imageobject>
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<imagedata fileref="images/lag2_ab01.eps" format="eps">
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</imageobject>
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</mediaobject>
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</figure>
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<para>
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</para>
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<figure id="X-087-2-cable.nullmodem.diagram">
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<title>Serial NULL-Modem cable</title>
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<!-- <graphic fileref="lag2_ab02.jpg"></graphic> -->
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<!-- 2016-01-28; MAB, TLDP -->
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<mediaobject>
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<imageobject>
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<imagedata fileref="images/lag2_ab02.jpg" format="jpg">
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</imageobject>
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<imageobject>
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<imagedata fileref="images/lag2_ab02.eps" format="eps">
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</imageobject>
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</mediaobject>
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</figure>
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<para>
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</para>
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</sect1>
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</appendix>
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