Digital Video Cables

2007-09-29T14:24:00.000-07:00

Digital Video

There are three commonly used interface protocols used for digital video in the consumer electronics industry. There are, of course, more than three but most of the others are endemic to the computer world. This article will only focus upon interface schemes commonly used between a source and an A/V Pre-Pro or consumer display device.

Firewire™, also known as IEEE 1394 or iLink™, is a digital communication standard that supports data transfer rates up to 800Mb per second. Invented by Apple Computer in the mid 1990’s, IEEE 1394 was soon adopted by the likes of Sony, Phillips, Panasonic, Canon, JVC and others where it is commonly used on digital camcorders, DVR’s and digital satellite receivers. Firewire is also used with some extended definition audio formats such as SACD and DVD-A.

Firewire (shown on the right) is a copper based interconnect that can reliably deliver a digital video signal up to fifteen or so feet. There are a few “flavors” of Firewire – 4/4, 4/6, 6/6, and Firewire 800. Most consumer digital video products and laptop computers will use the 4/4 or 6/6 configuration. There are no practical performance advantages (or disadvantages) inherent in these various choices. Check your owner’s manual to determine which cable is correct for your gear.

HDMI and DVI are semi-compatible, so you can purchase a cable with an HDMI connector on one end and a DVI connector on the other – perfect for connecting a projector or plasma display to an audio/video processor unit. Of course you can also get HDMI-to-HDMI and DVI-to-DVI interconnects.

DVI (Digital Visual Interface) is an uncompressed digital connection scheme originally developed for the PC industry. Initially designed as a low-cost, high-bandwidth digital connection between PCs and digital monitors, DVI is now the most widely used digital display interface in the computer industry. The EIA/CEA 861 protocol defines how DVI is used to connect a video source device to a digital television monitor (DTV Monitor). In home theater applications DVI may be combined with High-bandwidth Digital Content Protection (HDCP) technology to create a protected digital connection that prevents unauthorized duplication of appropriately encrypted programming.

Members of the Cable and Satellite distribution industries are supporting DVI with HDCP as part of their complete digital interface solutions. On July 25, 2001, a press release announced that four of the seven major motion picture studios joined the Cable and Satellite industries in endorsing DVI with HDCP.

DVI is a copper-based electrical interface that is effective to sixty feet or more. If significantly longer interconnect distances are needed a DVI “extender” device must be used. While common in the realm of PC’s, DVI connections on home theater products are found primarily on projectors, monitors, advanced DVD players and some satellite receivers. All home theater applications of DVI utilize the DVI-D standard in a single link configuration. DVI-D dual link will support up to a 1080p image, but that level of performance is rare (and very expensive) in today’s market. It is important to note that a DVI-D dual link cable is completely compatible with single link applications and offers the added benefit that as you upgrade components you won’t need to invest in new cables.

On April 16, 2002 Hitachi, Matsushita Electric (Panasonic), Philips, Silicon Image, Sony, Thomson and Toshiba announced the formation of a working group to define the next-generation digital interface specification for consumer electronics products. Designed to usher in the new era of digital entertainment, the High Definition Multimedia Interface (HDMI) specification combines high-definition video and multi-channel audio in one digital interface. This interface builds on the success of DVI, offering new features while maintaining full backward compatibility.

HDMI offers significant advantages over existing analog A/V interfaces. Its uncompressed, digital format transports high-definition video, multi-channel audio and control signals between components. By combining audio with video on one cable, HDMI offers a convenient connection alternative to the maze of existing analog A/V cables. HDMI also ensures compatibility between products. Capitalizing on the interoperability standards created in CEA (EIA/CEA-861x), HDMI assures that the best video format is always sent from source to display. HDMI is “backwards compatible” with DVI, so that an HDMI equipped source can digitally drive a DVI equipped display device.

HDMI, like DVI, is a copper based electrical interface. HDMI is effective to more than sixty feet, and ensures full performance in almost any consumer application. A small connector, HDMI interconnects also have the advantage of being able to slide through a conduit. This interface will become a preferred candidate for all kinds of custom installations. As this is being written, HDMI is available on more than 100 consumer electronics products from more than two-dozen manufacturers. There is little doubt that the future of home theater and high-definition entertainment will be intimately entwined with the HDMI protocol.

Clearly the world of digital signal interface has evolved in important and unexpected ways over the last few decades. Giant leaps in technology have become so commonplace that they are nearly taken for granted. Understanding the implications of this evolution in technology will most certainly pay dividends in the form of better audio/video performance and a longer lasting return on your investment in interconnect technology. As the old saying goes, change is the only constant.

Please visit Kongcable for all your audio and video needs including HDMI.

Founder and owner of Kongcable.com, Michael Mancini, lives in Columbus Ohio. Michael was born and raised in London, Ohio.

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Digital Video Connectors

Digital Video Cables