Thursday, August 20, 2015

What is HDMI

What is HDMI


What is H D M I (High Definition Media Interface)?

In simple terms, HDMI is an all digital connection that can carry high-definition video and several digital audio channels all over the same cable. HDMI was first officially unveiled in 2003 but it is only in the last few years that we have seen widespread support for the standard. During the development of HDMI several versions from 1.1 until now 1.4 have been developed. The different versions signify changes to the types of audio they can transmit, all versions should be able to transmit HD video up to 1080p.
1.0 was the first version of HDMI and was ratified in late 2002, it will decode most versions of audio content in DVD and digital TV signals including Dolby Digital and DTS. All HDMI Category 1 Cables are certified up to 720p/1080i.

1.1 this version added DVD – Audio support which means, users with compatible discs and players can listen to 5 channel audio streams without the need for six separate audio RCA cables.

1.2/1.2a: the main improvement of this version over the previous one is the addition of super audio CD support which means users no longer need to rely on I link or analogue cables to listen to super audio. The standard also adds support for an, as yet, unused type of PC connection.

1.3/1.3 a/1.3b/1.3c: these versions added support for Dolby and to high-definition and DTS – HD Master audio, which are used in Blue-ray players. Increasingly, audio and visual receivers are including decoding for these standards on board, while devices like the PlayStation 3 will output the coded signals. The 1.3 standard also increases the available bandwidth by a factor of 2 to 10 Gbps. Although versions 1.3b and 1.3c exist they don't add any further functionality over 1.3 a and so are interchangeable.

1.4 this is the product's biggest update since HDMI was released and introduces a host of new features and a modified cable design. The biggest new feature is the introduction of ethernet to HDMI, which allows a two-way hundred megabit connection to pass between two compatible components and means you will no longer need to wire your system up this land cables as well however, ethernet is an optional feature and not all versions of 1.4 cables supported. You should look for cables marked easy or ”with ethernet.

The 1.4 standard also supports 3-D in full 1080p resolution, where version 1.3 only supports 1080i resolution up to (3840/2160p).
HDMI v1.4 cables support up to 3840×2160 24Hz/25Hz/30Hz, 4096×2160 24Hz.
DSTV / Multichoice currently broadcast their HD Channel on HD 720 (1280 x 720) - 720p.

The new version allows for an audio return channel which is especially handy for television viewers. If you are watching your televisions on-board tuner it means you can now hear it through your sound system with just the single cable - no need for a separate optical cable.

Two new connector systems will also debut with 1.4, a new 19 pin HDMI Micro connector (type D) which is half the size of the current mini, and the automotive connection system (type E), which is designed to withstand the rigours of in car use.

Lastly, HDMI will now support photographic colour standards for better compatibility with digital still cameras.

The two standards are inter-compatible with each other, but to use HDMI ethernet you will need to own dedicated versions of 1.4 cable products, which support the new version. They have been available from early 2010.

But how does HDMI differ to analogue cables?
Analogue video cables, such as component, composite or s – video, are currently still the main methods used to transfer picture signals in an average home system. Component is a highest quality analogue cable, since it breaks down the picture signals into three different cables - one cable each for red, blue and green. When you have got analogue cabling connecting digital sources (such as an LC D or plasma screen with a DVD), the digital video or sound signals have to be converted into analogue to travel through the cable, before being reconverted back into digital at the receiving end. This could lead to some signal degradation and the resulting loss in output quality.

What are the advantages of going digital with HDMI?

HDMI can deliver high-quality sound or vision without the risk of quality loss due to the conversion or compression of the video or audio signal. HDMI pictures should be smoother and sharper with a distinct reduction in video noise. Sound should be crisp and taught, without any distortion. And of course using the single cable HDMI is a lot less messy, than all the additional cables snaking around your home theatre kit.

Because of its digital nature, HDMI also works well with fixed pixel displays such as LCD, plasma or DLP screens and projectors. And HDMI cable allows you to exactly match pixel by pixel in the native resolution with whatever source device you have got connected. HDMI systems will also automatically convert a picture into its most appropriate format, such as 16:9 or 4:3. HDMI has some built in smarts that allow you to control any device connected via HDMI through the one remote. Since the HDMI connection allows two-way communication between devices, it gives you basic universal remote like functions which for example, can tell the components in an HDMI linked system to turn on when you want to watch a DVD, just with the press of a button.

What is the difference between DVI and HDMI?

You may have heard of Digital Video Interface (DVI), which is another all digital connector for video. DVI has been around for longer, and can be found in many more televisions and other devices then HDMI. DVI was initially developed as a connection between PCs and monitors, but eventually found its way into the home entertainment world as well.
The HDMI standard is actually based on the DVI standard, therefore the picture quality should be the same. One advantage of HDMI is the capability of transmitting audio signals, which DVI cannot do, HDMI cables can also be longer than DVI cables, HDMI cables can be up to 20 m in length.
For more information about D V I and conversion from HDMI to DVI see our article on DVI.
(With thanks to CNET Australia).

Thursday, December 19, 2013

What is DVI

What is DVI (Digital Visual Interface)?
According to Wikipedia, DVI is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source to a display device, such as a computer monitor. It was developed with the intention of creating an industry standard for the transfer of digital video content.
The interface is designed to transmit uncompressed digital video and can be configured to support multiple modes such as DVI-D (digital only), DVI-A (analog only), or DVI-I (digital and analog). Featuring support for analog connections, the DVI specification is compatible with the VGA interface.[1] This compatibility, along with other advantages, led to its widespread acceptance over competing digital display standards Plug and Display (P&D) and Digital Flat Panel (DFP).[2] Although DVI is predominantly associated with computers, it is sometimes utilized in other consumer electronics such as television setsvideo game consoles and dvd players.
DVI connectors come in several different configurations, which look as follows:


From this it can be seen, that DVI is actually quite confusing, since the same connector (DVI integrated) can be used for both analog and digital output.
So, if one wants to convert from DVI to another format such as HDMI, composite, component or VGA
one needs to establish from the above, which type of DVI your equipment uses and also ensure from the equipment whether the output is digital or analog, if an integrated DVI connector is used.
From that it is easy to see, that conversion from digital DVI to HDMI would be easy and inexpensive,
since both use digital transmission, but a conversion from analog DVI to HDMI would be relative expensive,
since not only would the converter have to change the signals from analog to digital, but also up-scale to the higher resolution of HDMI.

Monday, April 30, 2012

RS232 or "standard" serial cables

DB25 PIN-OUT DB9 PIN-OUT

















Why does my RSS232 cable not work or the myth of the RS 232 not working debunked.


RS 232 serial is an ANSI standard, but there are so many variations of this standard implemented, that it is, for all intents and purposes, not a standard any more…
RS 232 is applicable to both DB9 and DB25 connectors. The connector on a PC is always a male connector; therefore, the connector on the cable must be a female connector. You can see from the tables above, that there are transfer and receive signals, so-called hand shake signals and a chassis- and a reference ground.
Whether the receive and transmit lines are connected cross over or straight depends on what kind of device (peripheral) one wants to link to a PC. The device can either be DTE, or DCE. A PC is normally a DTE device (data terminal equipment) a modem would be a DCE device (data communication device). The problem is that you normally don’t know what kind of device your peripheral is.
Another problem is the length of the cable, the standard allows for a maximum length of 15 m, but we have successfully implemented cables with 200 m and more, the links depends completely on your computer and your peripheral.
Perhaps we should here give a short explanation of what a serial standard is. The most common standards are RS232, USB, FireWire and SATA.
In these standards data is transmitted in a serial method, that means that all characters which are sent one after the other on one wire and all received characters are on a different wire, in comparison to a parallel method where all the bits are transmitted on a different wire.
Although all the above are serial standards the way of transmitting is completely different, therefore, a ‘translation’ has to be made from one standard to the other.
From the above, it might become apparent that a conversion from USB to RS232 can be difficult if one does not know what kind of device the RS232 peripheral is.
But if one knows, what type of device is to be connected, a cable can be built to change from the standard DTE to DCE and the required handshake.






Saturday, March 22, 2008

Computer and Electronic Cables and Connectors, protocol convertors, KVM switches

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We specialise in making up cables to your requirementsand can help you with technical advise,
cables, connectors, protocol conversions and KVM switches.
We have a large stock and invite you to have a look at some items we are presently overstocked in
and want to dispose off at really low prices.
The side is: http://www.volkirk.co.za to have a look and also visit our e-shop at http://www.customcables.co.za.