In the digital world, DVI (digital video interface) is a digital interface often employed in connecting a video source to a display unit, for example, a computer screen. In a move to shift from the analog to digital transfer of data, DVI was developed as the industry common set standard for transferring digital visual data.
The video technology optimizes the picture quality from the current video graphic cards and LCD screens. Due to their video quality, it is very rare nowadays to find a video card with no DVI ports. For a brief period, the home entertainment industry employed the DVI connections in the high-end TVs (HDTV), DVD players and satellites.
Currently, DVI format is more common in the computer world and the home theater resolving to HDMI use.
Different DVI formats
There are three types of digital interface connections;
The format employs a direct link between the data source and the display unit. The best example here is the relationship between a desktop computer and the LCD screen. The connection is made via a digital cable and no digital to analog conversion takes place. The data transmission is, therefore, faster and maintains its high quality.
The digital format interfaces DVI signal source to an analog display format for example to a cathode ray tube screen. Unlike DVI-D, there is a deviation in the signal quality on account of the digital-analog conversion. The most common use of the format is through the VGA ports.
This format uses DVI-integrated cables which can handle the two types of data transmission; analog to analog or digital to digital transportation. DVI-I cable is hence used in more cases due to their dual transmission capability.
It is wise to note that DVI-A and DVI-D cables can not be used to replace the other without an appropriate converter first.
Single and dual links explained
Both DVI-D and DVI-I have a single link and dual link connectors. The DVI cables transmit data using the TMDS (meaning transition minimized differential signaling) technology.
The major difference is that single link cables, as the name suggest employs one TMDS transmitter (at 165 MHz) while dual link uses two. For a more robust transmission (speed and signal quality), dual link DVI cables are hence preferred to the single link. Dual link guarantees a higher image resolution.
The maximum DVI length
The major issue in DVI transmission is the signal quality. Since the signal strength is a subject to the cable length, the official standard is 5meters signal range. However, a longer distance can be achieved with the use of a DVI signal booster.
How to choose the right cable
Carefully examine your product with the following details in mind:
• If either or both sides of the connection are DVI-D, then use DVID-D cable. But if DVI-A, go for a DVI-A cable.
• When one end is VGA and the other DVI, and the DVI compatible with analog format, then use a DVI to VGA cable
• If both connections feature DVI-I, then the best choice is the DVI-Integrated cable.
• However when one connection is analog and the other digital format, then a direct link is not possible except with the use of a converter like HDMI converter.