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.

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.

VDC would be the abbreviation for Volt Direct Current which translated would volts direct current. The idea of ??this type is unidirectional current to the load. Direct current is normally produced by batteries, thermocouples, solar cells and a dynamo electric machine type. The direct current can flow in conductors such as wires, but may also flow through semiconductors, insulators ... In the image: 1 - current per pulse 2 - Direct Current (DC) 3 - Alternating Current (AC) 4 - Variable Current

The meaning would be HDTV. It is used to indicate that the device is compatible with high definition. For high definition they have created three technical standards. ATSC, DVB and ISDB-T. Since 2005 the possibility of assigning HD Ready label as a kind of obligation to define the devices that have more than 720 lines (720p, 1080i at 50 or 60 Hz) was assessed.

1080p is an alternative name for the maximum resolution used in high definition television (HDTV). The number 1080 represents 1080 lines of vertical display resolution, while the letter p stands for progressive scan and non-interlaced.

One hertz is one cycle per second, meaning repeating cycle as an event. For example, hertz is applied physics measuring the number of times for a second wave (either acoustic or electromagnetic) is repeated or can be applied, among other uses, to ocean waves that reach the Beach vibrations per second or a solid. The quantity that measures the frequency hertz is called,in this regard, the inverse of the period. One hertz is an oscillation frequency of suffering a particle over a period of one second.

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 term VGA (Video Graphics Array or Video Graphics Adapter) is a graphics display system for PCs developed by IBM. VGA has become one of the standards for the PC image. In text mode, VGA provides a resolution of 720 by 400 pixels. In graphics mode, the resolution is either 640 by 480 (with 16 colors) or 320 by 200 (with 256 colors). The color palette is 262,144.Unlike earlier graphic standards for PCs - MDA, CGA, EGA and VGA - uses analog signals rather than digital signals. Since its introduction in 1987, several other standards have been developed that offer greater resolution and more colors (SVGA, XGA ...), but VGA remains the denominator used. All personal computers manufactured today still have support VGA, and possibly some other more advanced connection.

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.

The acronym "HDMI" stands for "High Definition Multimedia Interface".

The HDMI interface allows transmission of video and audio between devices, supporting video resolutions 480i, 480p, 576i, 576p, 720p, 1080i, 1080p, 1440p, 1600p.

Different HDMI versions

HDMi 1.0
- December 2002.
- Maximum transfer of 4.9 Gbit/s.
- Supports up to 165 Mpixels/s video mode (1080p or UXGA 60Hz) and 8-channel/192 kHz/24-bit audio mode.

HDMI 1.2
- August 2005.
- Added support for One Bit Audio, used on Super Audio CDs, up to 8 channels.
- Availability HDMI Type A connectors for PC.

HDMI 1.3
- June 2006
- Bandwidth 340 MHz.
- Data rate of 10.2 Gbit/s.
- Dolby TrueHD and DTS-HD,

HDMI 1.4
- Send video and audio HD
- Data and 3D video.
- FullHD to XHD (eXtended High Definition) up to 4096 × 2160 pixels (24 frames per second) or 3840 × 2160 (30 fps).
- Audio Return Channel that will need fewer cables to have a surround sound system connected to the TV.
- Built-in Ethernet connection cable with speeds up to 100 Mbit/s own.

HDMi 2.0
- September 2013
- Bandwidth of up to 18 Gbit/s
- 4K @ 50/60 (2160p) video
- Up to 32 audio channels to a multi-dimensional immersive experience
- Up frequency 1536kHz for maximum audio fidelity sound
- Simultaneous Delivery 2 streaming video to multiple users on the same screen
- Streaming audio up to 4 users
- Support theater angle 21:9 radio
- Dynamic synchronization of video and audio in streaming
- Extensions of CEC commands to control multiple devices from a single point.


Type HDMI

Type A (picture 1): It is the standard connector used in almost all devices.
Type B (picture 2): A connector rarely used.
Type C (picture 3): A connector widely used in tablets, smartphones and other devices.
Type D (picture 4): A connector used in smartphones.
Type E (picture 5): IA connector used for vehicles connectivity.