HDMI is a wired transmission technology of a digital signal, which is subsequently converted into images, video and audio. Today is the most common transmission option and is used in almost all computational technology, where video information is provided - from smartphones to personal computers.
About HDMI
The port has 19 contacts in all variations. The connector is also divided into several types, based on which you need to buy the desired cable or adapter for it. The following types are available:
- The most common and "large" type A and B, which can be found in monitors, computers, laptops, gaming consoles, TVs. B-type is needed for better transmission;
- C-type is a reduced version of the previous port, which is often used in netbooks, tablets, PDAs;
- Type D - occurs very rarely, as it has the smallest dimensions of all ports. It is used mainly in small plates and smartphones;
- E-type - a port with such marking has a special protection against dust, moisture, temperature drops, pressure and mechanical impact. Because of its specifics, it is installed on the onboard computers in cars and on the special equipment.
Types of ports can be disclosed among themselves in appearance or on special labeling in the form of a single Latin letter (there is not on all ports).
Cable length information
For wide consumption, HDMI cables are sold up to 10 meters long, but can occur to 20 meters, which is quite enough for the average user. Various enterprises, data centers, IT companies for their needs can buy cables for 20, 50, 80 and even more than 100 meters. For home use, you should not take the cable "with a margin", it is enough will be enough for 5 or 7.5 m.
Cable for home use is made mainly of special copper, which can no problems in short distances. However, there is a dependence of the quality of reproduction from the variety of copper, from which the cable is made, and its thickness.
For example, models from specially processed copper, standard labeling, a thickness of about 24 AWG (this is an area of diameter equal to about 0.204 mm2) can transmit a signal to a distance of no more than 10 meters in a resolution of 720 × 1080 pixels with a screen update rate of 75 MHz. A similar cable, but the High Speed Technology (you can meet the High Speed designation) with a thickness of 28 AWG (the area in diameter is 0.08 mm2) is already able to transmit a signal as 1080 × 2160 points with a frequency of 340 MHz.
Pay attention to the renewal frequency of the screen at the cable (it is indicated in the technical documentation or written on the package). For a comfortable viewing of video and games, the human eye is enough about 60-70 MHz. Therefore, it is necessary to chase the numbers and quality of the displayed signal only in cases if:
- Your monitor and video card support 4K permission and you would like to use their capabilities by 100%;
- If you are professionally engaged in video editing and / or 3D rendering.
The length and quality of signal transmission depends on the length, so it is best to buy a cable with a small length. If you for some reason you need a longer model, it is better to pay attention to the options with the following labeling:
- CAT - allows you to transmit a signal to a distance of up to 90 meters without any noticeable distortion in quality and frequency. There are some models that are written in characteristics that the maximum signal transmission length is more than 90 meters. If a similar model met you somewhere, it is better to give up the purchase, since the signal quality will be somewhat suffering. This marking has version 5 and 6, which can still have any letter index, this factors practically do not affect the characteristics;
- The cable made according to coaxial technology is a design with a central conductor and an external, which are separated by an insulating layer. Conductors are made of pure copper. The maximum transmission length of this cable can reach 100 meters, without loss in the quality and frequency of refreshments to video;
- The fiber cable is the most expensive and best option for those who need to transmit video and audio content for long distances without loss in quality. It may be difficult to find in stores, as in great demand, it does not use due to certain specifics. It is capable of transmitting a signal to a distance in more than 100 meters.
HDMI version
Thanks to the joint efforts of the six large IT companies in 2002, the version of HDMI 1.0 was released. Today, almost all further improvements and promotion of this connector, the American company Silicon Image is engaged. In 2013, the most modern version was 2.0, which is not compatible with other versions, so it is better to buy an HDMI cable of this version only if you are confident that the port on a computer / TV / monitor / other technique also has this version.The recommended version of the purchase is 1.4, which was published in 2009, as it is compatible with 1.3 and 1.3b versions, which came out in 2006 and 2007 and are the most common. Version 1.4 has certain modifications - 1.4a, 1.4b, which are also compatible with 1.4 without modifications, 1.3, 1.3b versions.
Types of cable version 1.4
Since this is recommended for the purchase version, then consider it more. There are five varieties of all: Standard, High Speed, Standard With Ethernet, High Speed With Ethernet and Standard Automotive. Consider each of them in more detail.
Standard - Suitable for connecting uncompaired home use devices. Supports permission in 720p. It has the following characteristics:
- 5 Gb / s - maximum bandwidth;
- 24 bits - maximum color depth;
- 165 MP - the maximum allowable frequency band.
Standard with Ethernet - has identical characteristics with a standard analogue, the only difference is to support the Internet connection capable of transmitting data at no more than 100 Mbps in two directions.
High Speed or Speed High. Having supported Deep Color, 3D and Arc technologies. The latter need to be considered more. Audio Return Channel - allows you to transmit and sound in full with video. Earlier in order to achieve excellent sound quality, for example, on a TV connected to a laptop, an additional headset was required. The maximum working resolution is 4096 × 2160 (4K). The following specifications are available:
- 5 Gb / s - maximum bandwidth;
- 24 bits - maximum color depth;
- 165 MP - the maximum allowable frequency band.
There is a high-speed version with Internet support. Internet data transfer rate is also 100 Mbps.
Standard Automotive - used in cars and can only be connected to the E-type HDMI. Specifications for this variety are similar to the standard option. The exception is only an increased degree of protection and a built-in ARC system, which is not in the standard wire.
General recommendations for choosing
The work of the cable is influenced not only by its characteristics, material manufacturing material, but also the quality of the assembly, which is not written anywhere and it is difficult to determine at first glance. Take advantage of the tips to save and select the optimal option. List of recommendations:
- There is a common misconception that cables with gilded contacts better spend a signal. This is not the case, the gilding is applied to protect the contacts from moisture and mechanical effects. Therefore, it is better to choose conductors with nickel-plated, chrome or titanium coating, as they provide better protection and cost cheaper (exception - titanium coating). If you use a cable at home, then it makes sense to buy cable with additional contacts no contacts;
- Those who need to transmit a signal over a distance over 10 meters is recommended to pay attention to the presence of a built-in repeater to enhance the signal, or buy a special amplifier. Pay attention to the cross-section area (measured in AWG) - the less its value, the better the signal to long distances will be transmitted;
- Try to buy cables with shielding or special protection in the form of cylindrical thickening. It is designed to support optimal transmission quality (prevents interference) even on very thin cables.
To make the right choice, it is necessary to take into account all the characteristics of the cable and the built-in HDMI port. If the cable and port fails, it is necessary to either buy a special adapter, or completely replace the cable.