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.

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.

Android Android is a kernel-based Linux operating system designed primarily for touch screen mobile devices such as smartphones or tablets, initially developed by Android, Google Inc. supported financially and later bought the company in 2005. IOS is a mobile operating system of Apple Inc. Originally developed for iPhone (iPhone OS), beingthen used in devices like the iPod Touch, iPad and Apple TV. Apple, Inc. does not allow the installation of third-party iOS hardware.

An Active Pixel Sensor (APS) is a sensor that detects light based on CMOS technology and therefore known as CMOS sensor. Because CMOS technology is possible to integrate more functions on a sensor chip, such as brightness control, contrast correction, or an analog-digital converter. Advantages

Much lower power consumption

Economic (requires few external components)

If readingtaneous higher number of pixels

The digital converter may be integrated on the same chip

Blooming low ("Smear") or no

Greater flexibility in reading (faster preview, video, ...)

The pixels can be exposed and read simultaneously

Other possible topologies (the SuperCCD Fujifilm sensor employs a panel-shaped construction (octagonal) forpixels)

Different types of pixels (depending on size and sensitivity) combined

High frame rate compared to a CCD of the same size

In the diagram we can see: 1) photo-diode. 2) Amplifier. 3) metal wire. 4) Output signal. 5) Light.

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.

The Wifi technology is a wireless communication mechanism between devices. This technology allows you to connect devices such as computers, laptops, mobile etc... to the Internet or communicate with the devices themselves.

Applications can be several, among the most common are the access points, ideal for giving and sharing a connection signal to multiple devices. It is the typical configuration of a home user.
Repeater, ideal to repeat and amplify weak signal.

The power and range between devices basically depends on the antenna and its hardware.

The wireless signals work under a unified standard regulations, the standard that is based on the IEEE 802.11. These include IEEE 802.11b, IEEE 802.11g and IEEE 802.11n working at 11 Mbit/s, 54 Mbit/s and 300 Mbit/s, respectively.
Being any device with a standardized protocol such technology can connect to another using the same technology, making it a kind of universal connection.

The wireless networks are characterized by the ease and convenience of making connections in infrastructure, since it is not necessary to perform network cable installations.
it also allows connecting a lot of devices to a single node.

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.