Hello, everyone!
Today, I will continue to explain UTP cables. Now, the theme is UTP termination.
For UTP cables, we use standard connectors (plugs and jacks) or punchdown. As I said in a previous article, the plug connector is often called the RJ-45. It is a modular 8 pin connector. The plug connector is the male connector on the end of patch cord. The connector on the wall socket is called the jack.
In order to eliminate or reduce crosstalk and return loss, it is necessary to keep the amount of wire in each pair untwisted. In addition, it is very important that the jacket from the wires is minimally removed.
The color of cable pairs is shown in the next picture.
Figure 1. UTP cable and color code
Each pair of wires consists of a colored wire and a white wire with one colored strip.
Based on the TIA-568 standard, there are two color codes for UTP cables - T568A and T568B. The only difference between these two standards is in the layout of pairs 2 and 3. They are reversed. We need to use one of these versions. We must not mix versions. In the next two figures, we can see T568A and T568B.
Figure 2. T568A
Figure 3. T568B
Normal or straight-thru UTP cables can be used to connect PCs and switches, routers, etc. Pin 1 is connected to pin 1, pin 2 is connected to pin 2, … and the last 8 pin is connected to the last 8 pin (next figure, left side). But, if we want to connect two PCs without a switch or router, we must use crossover UTP cables (next figure, right side). We can make crossover UTP cable very easy. We will make one RJ-45 to T568A color coding and the other end RJ-45 will be T568B.
Figure 4. Straight-thru and crossover UTP cables
UTP cables are terminated in telecom closets, computer rooms, etc. on patch panels. In the patch panels comes a large amount of UTP cables. UTP cables must be bundled and marked. Also, care must be taken during installation not to damage the cables, to prevent kinking or bending.
I will continue this theme on the next article >> UTP cable (3): UTP cable installation.
Thank you!
