123 lines
4.7 KiB
HTML
123 lines
4.7 KiB
HTML
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<h1>Getting Ready for SDF Dialup: Equipment</h1>
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<p>Typical requirements for dial-up networking:
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<ul>
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<li>an SDF DIALUP account (username, password, and access numbers)
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<li>a computer that supports PPP dial-up networking
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<li>a POTS (Plain Old Telephone Service) line (aka a "land line")
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<li>a two-wire phone cord with RJ-11 connectors
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<li>an analog modem (aka "56k modem" or "dial-up modem")
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</ul>
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<p>Assuming you've got the first two items taken care of...
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<h2>Getting a POTS line</h2>
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<p>You'll need to contact your local telco company for this;
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in the US this will usually be either one of the "baby Bells"
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like <i>Qwest</i>, or <i>Verizon</i>. Check your local telephone
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directory if you're unsure. Typical cost for a basic land line is
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around $25/month with all the taxes. About the only extra you might
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want is call waiting if your modem is V.92 (see below) and you don't
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want to miss incoming calls. Don't be surprised if the telco asks
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for a deposit and takes a week to activate your line...
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<h2>Phone Cords</h2>
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<p>These can be picked up almost anywhere; chances are you already
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have one. That said, the typical flat phone cord isn't ideal as there
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is barely enough copper to carry a signal and the pair isn't twisted.
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Best option is to get some connector crimps and modern communication
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cable and make your own cord. And don't stop at the phone jack; if
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the wires running to the customer service box are really old replace
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them too.
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<h2>Dialup Modems</h2>
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<p>"Modem" stands for <i>MOdulator-DEModulator</i> and is a device
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that modulates/demodulates an analog carrier signal to encode/decode
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digital information. Modems allow digital computers to communicate
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over analog telephone lines. In the case of dial-up, the modem is
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of "narrow band", ie. it operates within the traditional POTS
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frequency band of 0 to 4 KHz.
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<h3>Physical Types: In vs Out</h3>
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<p>There's basically two types:
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<ul>
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<li><b>Internal</b>: typically a bus-powered card installed inside a PC; sometimes
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integrated into the main system board. Examples are: ISA (obsolete),
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PCI (current), PCMCIA (obsolete), mini-PCI (current).
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<br><br>
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<li><b>External</b>: stand-alone units, typically with multiple indicator
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lights and external power supply. Most have legacy DB9 or DB25
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serial ports and use standard serial cables to connect to the PC,
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though USB-based units are also available. Various PCI/PCIe cards
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and USB adapters are available to add serial support to newer computers.
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</ul>
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<h3>Functional Types: Soft vs Hard</h3>
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<p>Modems can either be <i>HARD</i>ware or <i>SOFT</i>ware driven.
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Software modems (softmodems) require OS-specific drivers to function
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whereas hardware modems (hardmodems) rely on self-contained controller
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chips for functionality and are therefor generally OS-independent.
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<p>In general:
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<ul>
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<li><i>most internal modems are softmodems</i> (aka "WinModems") and often
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only work with Microsoft Windows OS
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<li><i>most external modems are hardmodems</i>, though some USB modems are
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driver-dependent (ie. softmodems)
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</ul>
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<p>Users in need of a hardmodem should look for terms like "controller-based"
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or "supports DOS/Linux/Mac OSX"
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<h3>Current Modem Protocols and Speeds:</h3>
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<p>Modern telco networks switched to digital equipment in the
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late 1990s; the V.90/V.92 modem protocols were designed to take advantage
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of those telco upgrades and make use of hardware compression to increase
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transmission rates up to 320.0 kbits/s.
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<ul>
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<li>V.90: cir. 1999; 53.3 kbit/s download and 33.6 kbit/s upload
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<li>V.92: cir. 2000; 53.3 kbit/s download and 53.3 kbit/s upload ; supports call-waiting
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</ul>
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<p>Most SDF Dialup access numbers support at least V.90. Older modems may work
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as well but at slower speeds - ie. V.34 modems operate at 28.8 kbits/s
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<h3>General Setup</h3>
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<p>Internal modems are easy: just install it in an open card bay,
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plug one end of the phone cord into the the modem jack, the other into
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the phone jack in the wall/baseboard. External modems work similarly
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except you'll also need to connect the modem to the computer via either
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a serial or USB cable, and of course plug in the modem's power supply.
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Once all the cables are connected, power up and configure the dial-up
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PPP network connection (see the Windows and Ubuntu examples).
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<h2>References:</h2>
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<ul>
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<li><a href="http://en.wikipedia.org/wiki/Modem">Wikipedia Modem page</a>
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<li><a href="http://en.wikipedia.org/wiki/Softmodem">Wikipedia SoftModem page</a>
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<li><a href="http://en.wikipedia.org/wiki/RJ-11">Wikipedia RJ-11 page</a>
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<li><a href="http://en.wikipedia.org/wiki/Serial_cable">Wikipedia Serial Cable page</a>
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</ul>
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<cite>$Id: dialup_equipment.html,v 1.2 2011/01/16 09:43:09 jgw Exp $</cite>
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