A rack is a metal support designed to house electronic, computer and communications equipment. The measures for the width are normalized to be compatible with most equipment manufacturers. They are also called racks, cabinets, cabinets or closets. Each column has holes at regular intervals called U rack units (Pictured: 4) grouped in threes. The height (Pictured:5) of the racks is standardized and external dimensions of 200 mm by 200 mm. Being normal that from 4U to 46/47U height width types (Pictured: 7). Standard 600 mm or 800 mm Types of background (Pictured: 6) The depth of the frame is not standardized, as this flexibility is granted (Pictured: 8) to the equipment. The most common are: - 450 mm - 600 mm - 800 mm - 900 mm - 1000 mm - 1200 mm Type 19-inch rack can find various types of 19-inch rack. Rack Mural (Pictured: 2): Used to accommodate electronic network. They are the smallest and are anchored to wall. Rack Pie (Pictured: 1): They are used primarily for servers, UPS and network electronics. Open Rack (Pictured: 3): Open Rack Racks are available only modelsstructure, eliminating doors and other accessories.

UTP cable is standard twisted pair is referred by its acronym UTP (Unshiedld Twiested Pair/Unshielded Twisted Pair). The major advantages of this cable are its low cost and ease of handling. Its main disadvantages are a higher error rate compared to other cable types and their limitations to work at high distances without regeneration. FTP is a type of cable caracteriza that each twisted pair is uniformly during creation. A comprehensive screening of all pairs is performed by a apantallante outer sheet. This technique allows to have similar characteristics to the shielded cable. STP is characterized by that each pair is covered with a metal mesh, in the same way that the coaxial cables, and the set of pairs is coated with a sheet apantallante. Referenced frequently with their acronym STP (Shield Twisted Pair/Shielded Twisted Pair)

The BNC connector is a connector type, quick connect/disconnect, incoporando more security connector for coaxial cable. Initially designed as a miniature BNC Connector Type C is a type of connector used with coaxial cables like RG-58 and RG-59 RF applications that required a quick connector, suitable for UHF and constant impedance to over a wide range.

CVBS is the acronym by which composite video is often referred to. The idea of this definition means Color, Video, Erase and Synchronized.

The most widely used cable is the already known coaxial cables with a BNC connector or RCA connector.

When we talk about RJ45 ("Registered Jack" 45) we refer to a telecommunications network interface for wired connection of voice and data equipment.

This connector has 8 pins or connections and may have a specific category depending on the data transfer speed and bandwidth (category 5e, 6, etc.)

The common application is their use in Ethernet network cables under TIA/EIA-568-B standard that defines the arrangement of pins (pinout), but can also be used for other applications.

- Direct pin diagram:

EIA-568A
Pin No.1: WHITE-GREEN
Pin No.2: GREEN
Pin No.3: WHITE-ORANGE
Pin No.4: BLUE
Pin No.5: WHITE-BLUE
Pin No.6: ORANGE
Pin No.7: WHITE-BROWN
Pin No.8: BROWN

EIA-568B
Pin No.1: WHITE-ORANGE
Pin No.2: ORANGE
Pin No.3: WHITE-GREEN
Pin No.4: BLUE
Pin No.5: WHITE-BLUE
Pin No.6: GREEN
Pin No.7: WHITE-BROWN
Pin No.8: BROWN

- Schematic of crossed pins:

The crossover cable has one end with EIA-568A scheme and the other one with EIA-568B.

Depending on the quality and type, network cables are classified into categories that help us know the characteristics of them.

The categories of network cables most commonly used are:

- Category 5
- Category 5e
- Category 6
- Category 6
- Category 7

As can be seen, category 5e (enhanced or improved) and category 6A (Augmented), are an improvement of categories 5and 6, respectively, which it has improved the top speed and bandwidth.

The higher the category, the higher the speed of maximum data, the maximum 100 meters distance as its standard.

You can see a table which shows the 5 categories, where V is the maximum velocity, D is the maximum and MHz frequency which can work away.

There are several cabinet heights according to the needs of the installation, this height can be measured in rack units (U).

Each rack unit or U is the distance between each horizontal separation to place the different accessories inside the rack. This distance is 1.75 inches that is equal to 4.4445 cm high.

For example, if we say that a rack is 8U we will understand that it has 8 units to install device orAccessories of 4.44 cm in height.

Normally these accessories, like trays, guides, strips, etc. Occupy a unit of U (1U), but we can find that other devices or accessories occupy more units, for example can be a rack box to install a PC, a UPS, etc. It can be said that there is also a half unit of U (0.5U), in this case, two units could be installed in a rack unit.

As far as I knowEndo the units of rack that occupy the devices that we are going to install we will know the height that we need for our rack.

The size of the rack unit (U) is based on the standard specification for racks defined in EIA-310.

One of the basic components in most electrical circuits or electrical installations are the fuses, the fuse is a capsule (B) that has metal ferrules (C) on its ends, in which a thin filament of alloy or metal (A) characterized by having a low melting point.
The fuse is placed in a specific point of the installation, and will serve to protect said installation frompossible damage due to electrical overload or voltage.
In their normal state the filaments have continuity at their ends (C, D). This over voltage causes this filament to heat up and break (C.1, C.2), not passing electrical energy and protecting the circuit while minimizing the risk of fire.

We can find all kinds of fuses, according to their amperage, design etc.
Among the most common we can findr:

• Cylindrical fuse glass material. They are usually used in most household appliances, power supplies, etc.
• Fuses for Blade vehicles. They are the fuses that protect the electrical installation of the vehicle, usually they are of the same type and design in most vehicles, according to their amperage they have a specific color.
• Brown = 5 A
• Red = 10 A
• Blue = 15 A
• Yellow= 20 A
• Colorless = 25 A
• Green = 30 A
• Fuses for mini vehicles: It is the same as the previous one but of a smaller size.
• Fuses for Maxi vehicles: It is the same as the previous one but of a larger size.
• Midi Fuses
• Mega Fuses
• Reed fuses
• High voltage or industrial fuses

Your symbol is represented as a box and a line that crossesA line or a line is a sinusoidal shape (E).