VAC would be the abbreviation of Volt Altern Current which would be translated Volts of alternating current. The difference between VDC is that its sinusoidal oscillation achieving a more efficient energy transmission.

The alternating current is the energy that we receive in our homes, it is generated in the power plants by means of alternators.

The intensity of this type of current varies with time, and changes direction 50 times throughsecond (50hz). The generated voltage changes in the form of sine wave so it is not constant.

In the image:

1. Current by pulsations.
2. Direct current (DC).
3. Alternating current (AC).
4. Variable current.

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.

We can find 3 types of jack connector, monaural TS connector (tip-sleeve), TRS (tip-ring-sleeve) and TRRS stereo plug (tip-ring-ring-sleeve) which is used in most mobile devices, tablets, MP3 etc ...
We can difference these 3 types of connectors according to their diameter:

1. 6.35 mm jack connector or TS.
2. 3.5mm minijack connector or TRS, is the most common, usually used in headphone's output of portable devices.
3. 2.5mm jack connector or TRRS.

It consists of a maximum of three connecting parts being called the largest mass or negative polarity and two smaller size located more towards the end of the connector,
The called positive that correspond to each channel, such three-part plug can transmit signals in two separate channels, also known as stereo signals. There's a mono version, consisting of only two parts, a negative and a positive.

A. Protector
B. Stem
C. Ring
D. Tip
E. Kindred
F. Ring (Signal Right)
G. Tip (Signal Left)

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.

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 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.

HD is the term used to differentiate the systems that generate, transmit or support HD content (High Definition) with those of standard definition or low definition (SD).

HD resolutions are usually at least 1280 x 720 pixels by taking the ratio "width x height". Being the height, 720 pixels, which make high resolution.