Twisted pair properties• Twisted pair is made of insulated copper wires that have been twisted around each other to form wire pairs• Twisted-pair cabling is divided into two categories – Unshielded Twisted Pair (UTP) – Shielded Twisted Pair (STP)
Unshielded Twisted Pair (UTP)• UTP is a set of twisted pairs within a plastic sheath• The common use for this type of cable is telephone wiring and LAN communications• Two popular UTP cabling types are Category 3 and Category 5 UTP• Newer types include Category 5e and Category 6
UTP installation• During UTP installation hardware connectivity generally is accomplished by using an RJ-45 connector
Shielded Twisted Pair (STP)• STP includes a protective sheathing around the copper wire• The twisted pair is wrapped in foil to cut down on outside interference and electromagnetic radiation
Cross Over and Straight Through• Cross-over: A cross-over cable is used to connect two computers via their NICs, without using a hub or switch. (Note: You can only connect two computers at one time, connecting three or more will require a hub or switch of some sort).• Straight-through: A straight-through network cable is just what the name implies, a cable that passes data straight through from one end to another. Straight-through cables are used for a variety of connections. (e.g. connecting a computer to a hub or switch, connecting a computer to a cable/ISDN/DSL modem, and linking switches and hubs together.)(Refer to your handout for standards)
Solid and Stranded Wire• Solid wire cable means that each one of the 8 wires inside the cable consists of one solid copper alloy wire.• Solid wire cable is usually used for wiring inside walls as it does not flex very easily and is intended for wires that will never move.• It has better conductivity than stranded cable, which means you can run Ethernet over farther distances with solid core.
• Stranded wire cable means that each one of the 8 wires inside the cable consists of a few dozen very fine hair-like strands that bend and flex very easily.• Stranded wire cable is usually used for making patch cables because of its flexibility (the wires wont break as easily from being moved around and twisted frequently).
RJ-45 Connectors• RJ-45 connectors - They usually come in bags of 50, 100 etc. Pay attention to the type of RJ-45 connector you get and make sure it is intended for the type of Cat5 wire youre using.• There are two different kind of RJ-45 connectors, depending on whether you use them with solid or stranded wire cable as mentioned above.• Using the wrong kind with the wrong cable will most likely result in a bad connection.
Network Tools• Crimping tool - While this is the expensive part of making your own cables, its only a one-time startup cost• A good crimping tool has a pair of wire cutters built in, as well as a blade to strip insulation.• It also might support crimping of other connectors such as RJ-11.
Step 1• Cut a piece of Cat 5 as long as you need. When you cut, remember the old saying: Measure twice, cut once.• Make sure the cut on each end is clean and straight
Step 2• Strip about an inch of the insulation off the cable. Cut it back nice and square. Some crimping tools such as the one used in this article come with a built-in wire stripper.• You put the cable in to a stop on one side of the cutter. It will cut the jacket the right length to make a perfect crimp.• It is extremely important that you only cut the plastic insulation/jacket and not the wire.• Damaging one of the 8 wires, even if you just nick it or partially cut it, will ruin your cable.
STEP 3• Untwist the wires. Youll notice that there are 4 pairs of multi-colored wires inside. Sort the pairs by color.• You should end up with wires color coded as follows: blue/blue-white, orange/orange- white, green/green-white, brown/brown- white.
Get the wires lined up and niceand straight. Then clip off thetop millimeter so that they areall the same length and stickout about half an inch from theinsulated part.
STEP 4Insert the wire in to the RJ-45 Connector.
Step 5• Double-check one last time that the wires are aligned correctly and all the way in. Then insert the RJ-45 connector into the appropriate opening of the crimping tool.• Give the handle a nice, tight squeeze without crushing the RJ-45.
TEST• Once your cable is finished, you should test it to make sure it works.• Insert the two ends of the cable into the jacks on the tester and watch the lights.• If they all light up, you have a good connection for each wire and the cable checks out
• NOW YOU CAN REPEAT THE SAME PROCESS TO MAKE A CROSS-OVER CABLE.
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