HDMI, as of today, is much less complicated than DVI, although this new technology is backwards compatible.

A Guide to Digital Video

Jeff Wolfgang | ComputerCableStore

A Guide to Digital Video
by Jeff Wolfgang, ComputerCableStore.com

HDMI, as of today, is much less complicated than DVI, although this new technology is backwards compatible.


Among the bold new world of digital video there exists a level of confusion concerning cable connector types and cross technology compatibilities. DVI technology alone has upwards of 5 different types of connectors, not to mention cable assemblies that include two different connector types, one on each end. Therefore, to quell this confusion, we at ComputerCableStore.com present this article detailing the technologies respectively named DVI and HDMI.

DVI, or Digital Video Interface technology came about in 1999 as a result of the formation of the Digital Display Working Group (DDWG) a year prior. Their original mission was to create a standard digital video interface for communication between a Personal Computer and a VGA monitor. Recently, however, the consumer electronics industry began implementing DVD players, set-top boxes, televisions, and LCD/plasma monitors with DVI technology. DVI, having been designed to transfer uncompressed, real-time digital video, could support resolutions of 1600x1200 and above on a PC, and HDTV resolutions of 720p, 1080i, and 1080p. DVI connections are made up of either single or dual TMDS links depending on the amount of bandwidth needed for the desired resolution and refresh rate of the display device. DVI also implements HDCP, a form of digital copyright protection.

In addition to single link or dual link DVI cables, connectors can be broken down into three main categories. The three different types of DVI are DVI-D, DVI-I, and DVI-A. DVI-D is strictly digital, supports dual link, and contains 24 pin contacts arranged in three rows of eight. DVI-I has the original 24 digital contacts, as well as five additional contacts to support analog video. DVI-I also supports dual link. DVI-A on the other hand, is only available as a male connector or plug which only mates with the analog contacts of a DVI-I connection. DVI-A is used to convert between DVI and the traditional analog display technologies.

For those applications wherein a source device has a digital only DVI output to be connected to a display which has a digital only DVI input a DVI-D cable would be required. We can remember this obviously by the mere fact that the word "digital" begins with a D. Other digital technologies are also compatible with DVI-D such as P&D (Plug and Display) digital, commonly referred to as an M1 connection, and DFP or Digital Flat Panel connections. If you are looking for DVI-D to DVI-D, DVI-D to DFP, or DVI-D to P&D cables, click here. Please take note that the reason you can not find such cables as DVI-D to DVI-A or DVI-D to SVGA is that these connections are incompatible by definition. The reason for this is as follows.

The development of DVI-D by itself, being digital only, would have made connecting a DVI source to the traditional, and still very common, analog display impossible without first converting the signal. As of today, however, this option is more expensive than its worth, thus DVI-A and DVI-I were developed to incorporate analog technologies into the DVI Interface. A DVI-A cable will always have a male DVI-A connector on one end and some type of analog connection at the other, such as the VGA / SVGA HD15 connector or the P&D analog connector, both of which you may choose to purchase by following this link. The DVI-A end will always, without exception, plug into a female DVI-I connection and never into a DVI-D connection.

Finally, DVI-I incorporates both digital and analog signals in one interface, although only one can be used at a time. What is meant by this is that if the display only accepts analog, then only the analog contacts will be in use. At no point will any digital information be transmitted, and vice versa. Remember that connecting a DVI-D source with a pair of chained DVI-I and DVI-A cables to an analog display will not work, as the digital output in no step of the process gets converted to an analog signal. To connect to an analog display the source must have a DVI-I output to start with. Only then can you connect a DVI-A cable with the appropriate analog connector at the opposite end for connecting to an analog display. To find reasonably priced DVI-I cables, click here.

This concludes our section devoted to DVI, bringing us to the newer, more versatile HDMI or High-Definition Multimedia Interface technology developed by the HDMI Working Group in 2002. HDMI, as of today, is much less complicated than DVI, although this new technology is backwards compatible, meaning all of the new devices supporting HDMI can be connected to devices supporting DVI with an HDMI to DVI cable, which can be found here. This compatibility, however, is limited to the digital video signals only and does not include the extra features incorporated into the HDMI technology.

In addition to its ability to transmit uncompressed digital video, HDMI can also simultaneously handle uncompressed and compressed multi-channel audio as well. What this means is that it has the ability to turn upwards of 10 separate cables, audio and video, into one easy to install, small connector cable, which is quickly becoming very attractive to the consumer electronics industry.

Another impressive feature incorporated into the HDMI technology is Consumer Electronics Control (CEC) support based on the AV.link protocol allowing all devices connected within the HDMI system to be controlled using a universal remote, and its bi-directional communication between those devices allows for intelligent rendering of specified formats. For a full list of CEC functions click here.

This wraps up our article on high definition digital video interface technologies and their respective compatibilities. If you should have any further questions please refer to DviHdmiCables.com or send an email to jwolfgang@computercablestore.com. And remember, the ComputerCableStore.com has the widest selection of quality networking and audio/video cables at the best prices, in stock at all times.


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