Jun 072012

12If you have to connect two computers, you will need Ethernet (LAN cable). The cables with terminals, which you can buy in stores, i.e. the so-called ready-made cables, are more expensive and do not always have the required length.

cross cable

Cross cable

In order to make a LAN cable with connectors, we will need 3 things: an Ethernet cable (UTP or FTP),


UTP cable

crimping pliers for Rj45,

клещи за кримпване

crimping pliers

Rj-45 connectors.


Rj-45 connector

Computer cables may be mainly of two types – CAT5e and CAT6. The cables of the second type – CAT6 have better performance characteristics and are about 20-30% more expensive. Furthermore, the cables can be UTP or FTP. FTP cables have shielding below the external insulation which keeps the cable from high-frequency interference.


FTP cable

The way of arrangement of wires can be of two types: standard or crossover. There is also the so-called rollover cable.


The standard arrangement is used in almost all cases. The cables are arranged in the following sequence: orange-white, orange, green-white, blue, blue-white, green, brown-white, brown. This is standard 568V. It serves to connect the computer to the wall jack. We can see that the green wire is placed after the blue ones. This is done in order to form longer lines. The layout is the same at the other end of the cable.

The inverted (crossover) arrangement of wires in the connector is used for directly connecting one computer to another, without using a router, a switch or a hub. It is also used for connecting a router to a router and other identical devices. This is standard 568A. On one side of the cable is used the above-mentioned arrangement, and on the other side the arrangement is: green-white, green, orange-white, blue, blue-white, orange, brown-white, brown.





The rollover cable, also known as a cisco console cable is used to connect the computer terminal to the router. This cable is flat and is often colored blue so that it distinguishes from other network cables. It has complete transposition, i.e. conductor 1 goes to position 8, conductor 2 goes to position 7, etc.


Strip the jacket of the cable by cutting lengthwise with snips or a knife along the side of the cable. You need to do this very carefully, taking care not to injure the insulation of the individual wires. After removing the outer insulation, there should be about 2.5 cm. or 1 inch between the wires and the cable terminal. Then the wires are arranged according to one of the two examples, listed above, and are aligned by cutting with scissors or small cutters of about 1.3 cm. or 0.5 inches. Most modern crimping pliers have such tips.

клещи за кримпване на телефонни и компютърни кабели

Take the connector, the flat side toward you, the clip has to remain underneath. Plug the cable into the connector, being careful not to displace the terminals of the wires. The wires must reach the very end of the jack, and the ending of the outer insulation must go inside the connector. Inspect connector Rj45 from above. The terminals of the wires must be between the metal plates at the end of the jack. When you are sure that everything is okay, insert the connector into the crimping pliers and press firmly. The crimping pliers will slitter each of the eight wires anchoring it in the connector.

After you remove the connector from the pliers, the cable will be ready to use. You just need to repeat the operation at the other side of the cable. You can then use a cable tester to make sure the cable works correctly when both ends are crimped. It should be borne in mind that when the length of a LAN cable is more than 100m, the high quality of the signal is not guaranteed and you will have to place an amplifier on the routing.





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