mirror of https://github.com/tLDP/LDP
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@ -2,8 +2,6 @@
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<title>Media-Types</title>
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Media Types
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<para>
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Common network media include twisted pair (UTP and STP), coaxial cable,
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fiber-optic cable, and wireless transmissions via infrared and radio waves.
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@ -12,10 +10,12 @@ their vulnerability to EMI and eavesdropping, their bandwidth, and the
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maximum distance at which they can be used.
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</para>
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Twisted Pair Ethernet Cable
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<para><variablelist>
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Unshielded Twisted Pair (UTP)
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<varlistentry><term>Twisted Pair Ethernet Cable</term>
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<varlistentry><term>Unshielded Twisted Pair (UTP)</term>
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<listitem><para>
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<para>
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UTP is the most common type of network cable in use today. UTP consits of
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one or more pairs of insulated copper wires. The wires are twisted together
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@ -44,6 +44,8 @@ and Category 5 is the highest-quality network cable. The UTP categories and
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the bandwidth they support are summarized below.
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</para>
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<para>
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<screen>
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Category Maximum Data and Transfer Rate Description
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3 10 Mbps Least expensive network cable, commonly used
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4 16 Mbps Medium quality; rarely used
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@ -52,9 +54,11 @@ Category Maximum Data and Transfer Rate Description
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> Start Binh
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5 1000Mbps Highest Quality
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> End Binh
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</screen>
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</para>
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Shielded Twisted Pair (STP)
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<varlistentry><term>Shielded Twisted Pair (STP)</term>
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<listitem><para>
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<para>
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STP cable is similar to UTP, but inclues a foil or wire mesh shield
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between the wire pairs and the outer insulation. The shield is electrically
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@ -68,8 +72,11 @@ susceptible to EMI and eavesdropping. The reduced inteference allows for higher
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bandwidth, potentially as high as 500 Mbps.
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</para>
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Coaxial
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</para></listitem></varlistentry>
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<varlistentry><term>Coaxial</term>
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<listitem><para>
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<para>
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Coaxial Cable consists of a single thick copper wire surrounded by an
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insulator. A shield surrounding the insulator is used as the second conductor,
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@ -104,8 +111,8 @@ RG-62 93 ohms ARCnet
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</screen>
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</para>
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Fiber Optic
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Fiber Optic</term>
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<listitem><para>
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<para>
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A fiber optic cable consists of a thin glass or clear plastic fiber encased
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in a protective jacket. Signals are sent through the cable in form of light.
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@ -119,7 +126,7 @@ high bandwidth (up to 2 Gbps (gigabits per second) and extremely low attenuation
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Fiber cable can reach distances ranging from severak miles for multimode cable
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to hundreds of miles for single-mode cable.
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Infrared
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Infrared</term>
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<para>
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Wireless infrared networking systems are modulated beams of infrared light to
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@ -196,7 +203,6 @@ nearly global range. The bandwidth can be as high as 10 Mbps, but the satellite
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relays cause delays that may impair real-time communication. These systems are
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more expensive than wireless communication.
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<para>
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Please note that any information after this point in this section is largely
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redundant as these technologies have been superceded (from the perspective of
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@ -204,86 +210,7 @@ being economically more viable and also technologically superior) by
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those that have been outlined above.
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</para>
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Serial NULL Modem cable
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<para>
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Not all NULL modem cables are alike. Many null modem cables do little more
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than trick your computer into thinking all the appropriate signals are present
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and swap transmit and receive data. This is ok but means that you must use
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software flow control (XON/XOFF) which is less efficient than hardware flow
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control. The following cable provides the best possible signalling between
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machines and allows you to use hardware (RTS/CTS) flow control.
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</para>
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<para>
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<screen>
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Pin Name Pin Pin
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Tx Data 2 ----------------------------- 3
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Rx Data 3 ----------------------------- 2
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RTS 4 ----------------------------- 5
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CTS 5 ----------------------------- 4
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Ground 7 ----------------------------- 7
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DTR 20 -\--------------------------- 8
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DSR 6 -/
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RLSD/DCD 8 ---------------------------/- 20
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\- 6
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</screen>
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</para>
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Parallel port cable (PLIP cable)
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<para>
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If you intend to use the PLIP protocol between two machines then this
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cable will work for you irrespective of what sort of parallel ports you
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have installed.
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</para>
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<para>
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<screen>
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Pin Name pin pin
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STROBE 1*
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D0->ERROR 2 ----------- 15
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D1->SLCT 3 ----------- 13
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D2->PAPOUT 4 ----------- 12
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D3->ACK 5 ----------- 10
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D4->BUSY 6 ----------- 11
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D5 7*
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D6 8*
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D7 9*
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ACK->D3 10 ----------- 5
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BUSY->D4 11 ----------- 6
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PAPOUT->D2 12 ----------- 4
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SLCT->D1 13 ----------- 3
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FEED 14*
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ERROR->D0 15 ----------- 2
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INIT 16*
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SLCTIN 17*
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GROUND 25 ----------- 25
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</screen>
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</para>
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Notes:
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· Do not connect the pins marked with an asterisk `*'.
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· Extra grounds are 18,19,20,21,22,23 and 24.
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· If the cable you are using has a metallic shield, it should be
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connected to the metallic DB-25 shell at one end only.
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<para>
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Warning: A miswired PLIP cable can destroy your controller card. Be very
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careful and double check every connection to ensure you don't cause yourself
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any unnecessary work or heartache.
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</para>
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<para>
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While you may be able to run PLIP cables for long distances, you should avoid
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it if you can. The specifications for the cable allow for a cable length of
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about 1 metre or so. Please be very careful when running long plip cables as
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sources of strong electromagnetic fields such as lightning, power lines and
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radio transmitters can interfere with and sometimes even damage your controller.
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If you really want to connect two of your computers over a large distance you
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really should be looking at alternatives such as obtaining a pair of thin-net
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ethernet cards and running some coaxial cable.
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</para>
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- Serial NULL Modem cable
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- Parallel port cable (PLIP cable)
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</sect1>
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