Building a Home Network, Part 3: The Wiring
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In the first two articles in this series, "Building a home network, part 1" and "Building a home network, part 2: Your Internet service," I explained the components and costs associated with building a local area network (LAN) and with setting up Internet access. By this point, you should have a basic idea of what components you plan to use on your network, and you should have some idea of the network's layout. In this article, I'll show you how to start building the network by installing the hub and the cabling.
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Before I Begin
Before I start explaining the home networking techniques that this article will outline, I should say a few words about safety. There's nothing particularly dangerous about running twisted pair cable. (I'll assume that you're using category 5 cable for the purposes of this article.) Category 5 cable in 10 Base-T or 100 Base-T installations doesn't carry high voltage. Because of this, you don't have to worry about electrocuting yourself or frying your computers if you make a mistake. The worst thing that can happen if you make a mistake is that the network won't work until you've corrected the error.
However, just because there's no real danger associated with the cable itself, it doesn't mean there's no danger associated with the installation process. Depending on your individual home, you may be crawling into the attic to install cable or drilling holes in walls and fishing for cable. Needless to say, such activity does expose you to some level of danger—for example, you could fall from a high place or accidentally hook an electrical wire inside a wall. If you're uncomfortable with the thought of exposing yourself to these or other potential risks, I recommend that you have the cable installed by a professional.
Installing the Hub
Now, for those of you I didn't scare off, the first step is to find a good location for your hub. The ideal location will depend on the size and type of hub. For example, if you're using a 4-port hub to link two computers that are right next to each other, there's no reason you couldn't simply place the hub on your desk and use pre-manufactured patch cables to connect the PCs to the hub. Doing so would be much cheaper than buying a box of cable and some RJ-45 connectors.
If, on the other hand, you're using a 16-port hub to connect PCs all over the house, you'll have to be a little more choosey about your location. An ideal location would be an empty closet with a drop ceiling.
Whatever location you choose, you should look for three crucial things. First, there should be ample room. Larger hubs usually contain fans that are designed to keep them cool. There should be ample room around the hub for these fans to get plenty of air circulating through the hub.
Second, the location should be easy to wire. Every network connection must connect to the hub. Therefore, you'll want to put the hub in a place where it will be easy to get wires in and out of. Since you'll also have to place RJ-45 connectors on each wire (which tends to be a tedious process), you'll also want to make sure that you have plenty of room to work in and good lighting.
Finally, make sure you've located the hub in a central location. Or, at the very least, make sure that the hub is located within 300 feet of each of the PCs you're going to connect to it. If you have a large house, plan to run cables up and down walls from one corner of the house to the other or to a garage—measuring the distance you're running the cables first, of course. Ethernet signals don't transmit reliably at distances greater than 300 feet.
The actual installation of the hub is easy. Many larger hubs contain a pair of brackets in order to hang the hub on a network rack. In a closet situation, you could easily hang the hub on a pair of two-by-fours to save yourself the expense of buying a rack. Of course, you can also sit the hub on a shelf, assuming you have ample room for wiring and ventilation.
Running the Cable
Now that I've shown you how to mount the hub, it's time to run the actual network cable. The technique for this will vary widely depending on your individual installation.
When it comes to installing cable, basements, attics, and drop ceilings will be your best friends. Such places make it very easy to install cable. The reason for this is that you can run cable on top of a drop ceiling or along the rafters in a basement or attic with a minimum of drilling and fishing for hidden wire. Therefore, before you begin the actual wiring process, you should look at the locations that you plan to wire to see if any of these things are available.
When you're ready to begin, it's usually easiest to start wiring from the place where your hub is located and run the wire to the PCs from there. Category 5 cable comes in a box that contains an internal spool of wire. Such boxes contain a place where the wire feeds through the side of the box. You can simply place the box of wire on the floor near the hub and pull wire strait from the box.
If you're planning on running multiple cables to the same location, don't worry about getting the wire to the exact location just yet. Just get it fairly close. However, be sure to leave plenty of extra wire at both ends. The reason for not running the wire to the exact location at which it will be installed is that it's often difficult to reach the exact location. If you're running two or more wires to the location, it's easier to get the wires close to their final position and then tape the wires together before completing the installation. That way, you'll only have to pull wire through a difficult spot once, rather than doing it once for each wire.
This is especially true if you want the wire to come out of a wall. The secret behind doing this is that most walls are hollow. Often, if you can get into the attic or look above a drop ceiling, you can see right between the walls.
First, make sure you can actually get into the wall from above. Once you've confirmed this, cut a small hole in the dry wall in the location where you want the wire to come through. Next, feed the wires into the wall from above. If you have a bundle of wires that are taped together, this should be pretty easy. However, if you only have a single wire, you need to make a loop in the wire and secure the loop with tape—this way, you'll have something to grab onto.
Now, lower the wire through the wall and get it as close to the hole as possible. If you have difficulty locating the hole from above, try shining a flashlight into the hole.
Once you have the wire in position, use a bent coat hanger with which to push into the hole and grab the wire, then pull the wire through. If you have difficulty getting the wire through the hole, it may be necessary to enlarge the hole.
Be careful to avoid any fluorescent lights you've installed or any motors if you're running cables to a shop area. These devices give off electromagnetic fields that can interfere with the data on the wire. Category 5 is pretty good for resisting such interference, but it's not impervious. You'll reduce headaches later if you can cable your way around these things.
Jacks or Connectors?
Now you have a decision to make. Do you want to use jacks, or do you want to plug the cable directly into the PCs? There are advantages to both methods. Using jacks is cosmetically more appealing, especially if you've just fished cable through a hole on the wall. It also offers you a way to reach the PC easily if you find that the cable you pulled was just a little too short. Simply connect the PC to the jack with a patch cable, and you're in business.
On the other hand, there's definitely something to be said for putting RJ-45 connectors onto the wire that you've already pulled. Doing so often involves less work than installing jacks and offers fewer potential points of failure.
Installing the RJ-45 Connectors
Before I begin installing the RJ-45 connectors, it's important to point out that the method outlined in this article is only one method that works. It's by no means the proper method—if a proper method even exists. It's simply a written compilation of practical experience.
What Do I Need?
To place RJ-45 connectors on the wire, you must have three things: the wire, the RJ-45 connectors, and a crimp tool. Preferably, the wire should be of the category 5 grade and capable of 100 megabit data speeds. There's nothing special about the RJ-45 connectors, and you can buy a crimp tool for about $40 at the same place you buy the connectors. The RJ-45 connectors typically sell for 25 to 50 cents each. Be sure to buy plenty of extras since installing them is tricky, and you'll probably make mistakes. Once a connector has been crimped, it can't be reused if you've made a mistake. Don't let the mistakes frustrate or discourage you. Attaching RJ-45 connectors is the most annoying and tedious part of running network cabling.
Preparing the Wire
Once you have your materials together, you need to prepare the wire. Most crimp tools have two blades on them. One blade is designed to cut completely through a cable, while the other is designed to strip the insulation.
Begin by cutting about a quarter inch from the end of the cable so that all of the wires inside the cable are at the exposed end. Now, use the stripper blade to remove about an inch of insulation. You should be careful not to press too hard when stripping the insulation because it's very easy to cut the wires inside the cable accidentally. The best technique is to cut the insulation only about half of the way around, and then pull it off with your hand.
Once you've removed the insulation, you'll find eight wires and a string inside the cable. Untwist all of the wires, and cut the string off. When you've untwisted all of the wires, arrange the colors from left to right in the following order:
When you've arranged the wires in the necessary sequence, try to place them as closely together as possible between your fingers without getting them out of order. When you've accomplished this, cut off about a half-inch of the exposed wires, so that all of the wires end at the same place. It's normal for some wires to be longer than others, since they may have to wrap around other wires to reach the appropriate position.
Adding the Connector
Now, slide the RJ-45 connector onto the wires with the clip facing away from you. The connector has eight slots inside, one for each wire. When the connector is in place, you should verify that all of the colors are still in the correct order. You should also check the end of the connector to make sure that all of the wires go all the way to the end. The insulation of the wire should reach just beyond the crimp point.
If the insulation doesn't reach far enough inside the connector, or if all of the wires don't reach the end, pull the cable back out and clip a little off of the wires to make them the appropriate length. If the insulation extends too far into the connector, simply trim off a little more insulation.
When the cable fits correctly into the connector, verify the order of the colors one more time and then crimp the connector. This requires a little bit of strength and may require you to use two hands.
When the connector has been crimped, inspect the color order, and make sure that all of the wires still go all the way to the end of the connector. Finally, gently pull on the connector to make sure that it's secure.
Installing Wall Jacks
There are many different kinds of wall jacks. Typically, the jacks contain a piece that snaps to the bare wire. This piece then snaps into the jack itself, which then is screwed into the wall in the same manner as a light switch or an electrical outlet. The part of the jack that connects to the wire usually has color codes marked on it, so you'll know where to place each wire.
Testing the Connections
Once you've installed your cables and hubs, it's time to test them. There are several different ways of completing this task. The easiest is to use a cable tester. Unfortunately, cable testers are often very expensive.
If you don't have a cable tester available, try using a laptop to go around to each network port and test the integrity of each connection.
If you don't have a laptop available either, you'll have to test each connection as you set up the PC that will use the connection.
By now, you probably have a twisted and tangled mess of cable strung all over your house. Fortunately, there are some things that you can do to tidy up a bit. The first thing you should do is to attach the cables that are run together to each other. For example, if you have a bundle of five cables that run the length of your house, you could wrap a piece of tape around the cables every few feet or use wire ties to bundle the cables together.
Second, you should make a trip to the hardware store and find brackets that are designed to secure electrical wire. Bundling the wire together and securing it with brackets makes the cables look more like a network, and less like a firetrap.
Brien M. Posey is an MCSE and works as a freelance technical writer and a network engineer for the Department of Defense. If you'd like to contact Brien, send him an e-mail Brien_Posey@xpressions.com . (Because of the large volume of e-mail he receives, it's impossible for him to respond to every message. However, he does read them all.)
The above article is courtesy of TechRepublic http://www.techrepublic.com .
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