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HDMI and DVI Cables

HDMI is a digital signal format, developed primarily as a platform for the implementation of HDCP (High Definition Content Protection) to prevent consumers from having complete access to the contents of high-definition digital recordings. As one might expect from a standard that was developed to serve the content provider industries, rather than the best interests of the consumer, HDMI is something of a mess. The signal is not robust over distance because it was designed to run balanced when it should have been run unbalanced (SDI, the commercial digital video standard, can be run hundreds of feet over a single coax without any performance issues); the HDMI cable is an unnecessarily-complicated rat's-nest arrangement involving nineteen conductors; switches, repeaters and distribution amplifiers, by virtue of this complicated scheme, are made unnecessarily expensive; and the HDMI plug is prone to falling out of the jack with little more than a light tug. As more and more manufacturers move to implement HDMI on more home theater devices, however, it falls to the consumer to try to make the best of this dubious and poorly-thought-out standard.

BJC Series-1 Belden Bonded-Pair HDMI and HDMI/DVI Cables:

HDMI is a fragile interface, not least because of the difficulties of manufacturing twisted-pair cable to the fine tolerances required to handle the extraordinary bandwidth requirements of the HDMI signal. To overcome those difficulties, we sought the help of Belden, the world's technology leader in communications cable products, and we asked Belden to use its patented, exclusive Bonded-Pair technology to build us an HDMI cable with extraordinary impedance stability and low skew. The result: the BJC Series-1 Parallel Digital Video Cable. This is the only HDMI cable on the market incorporating bonded-pair technology; it is also, to our knowledge, the only HDMI cable made in the United States, built in Monticello, Kentucky and Richmond, Indiana. (One note: at the moment, we are having final assembly, i.e., connectorization of the cable, done under contract in China. We anticipate bringing final assembly home to the U.S. as well, but are working on production issues which have to be resolved before we can do that and still sell the cable at a reasonable, economical price.) The Series-1 is rated for in-wall installation, and has a CM rating--higher than the CL2 or CL3 ratings typically seen on home theater cabling. The acid test of any HDMI cable is its ability to convey signal over distance, and here the Series-1 Bonded-Pair cable excels; in our in-use testing, we have run 1080p/60 video 125 feet without degradation. Read more details, and view specs, on our BJC Series-1 Bonded-Pair HDMI Cable.

BJC Series-F HDMI and HDMI/DVI Cables: If the bonded-pair Series-1 HDMI has a drawback, it's stiffness--the cable is relatively thick and stiff, as a result both of the bonded pair construction and of the use of solid conductors. For shorter runs, it's often important for cable to be reasonably flexible so as not to exert too much pressure on equipment jacks or resist going around bends, and for those sorts of applications, we offer our Series-F cable. This cable is also made in the U.S. by Belden, and terminated (for now) in China, but instead of the 23.5 AWG solid copper conductors of the Series-1, it uses 26 AWG stranded copper conductors, resulting in a substantially more flexible cable.

BJC Series-2 HDMI Cables: In addition to our new Belden-built cables, we continue to offer our more economical, Chinese-sourced Series-2 HDMI cables. These cables are of excellent quality and we have found them dependable up to lengths of 50 feet at all resolutions up to 1080p/60. They are rated CL2 for in-wall installation, and use 24 AWG silver-plated copper signal conductors.View the drawing and spec sheet on our Series-2 HDMI and HDMI/DVI Cables, in .pdf format.

DVI/HDMI Cables: All of the cables above are available in DVI/HDMI configuration as well as the standard HDMI/HDMI configuration. DVI/HDMI cables have a single-link DVI-D connector on one end and an HDMI connector on the other. These cables function equally well in either direction: HDMI to DVI, or DVI to HDMI. We're often asked why there isn't a DVI-I to HDMI cable or a DVI-D Dual Link to HDMI cable; the reason is that HDMI (at least, the 19-pin version of HDMI implemented on all consumer HDMI devices) is a single-link, digital-only standard, so there's no way to hook it up either to a DVI analog or Dual-Link signal; one could put the DVI-I or Dual-Link type connector on the cable, but the additional pins at the DVI end wouldn't actually be hooked up to anything. In principle, HDMI is supposed always to be backward-compatible with DVI, so that any HDMI device should work with any DVI-D single-link device. In practice, although the two almost always work together, it's not uncommon to run into device compatibility issues.

DVI Cables:

While HDMI may not be a very good standard, it is at least not confusing; the same can't be said for its older sibling, DVI. The DVI standard has presented a couple of distinct challenges for home theater builders. The numerous different types of DVI plug, the different types of signal that can be carried in a DVI cable, and the often frustrating restrictions on run length have led to a lot of questions, and we'll try to clear some of those up here.

First, when you're looking for a DVI cable, it's important to be sure you know what type of signal you need to carry. The DVI connection can be used either to carry a digital video signal (DVI-D) or to carry an analogue signal (DVI-A) or both. The only way to be sure what your device accepts or puts out through the DVI connector is to examine the connection point and consult your manual. At right are pictures of a DVI-D plug (digital only) and a DVI-I plug (used for analogue video, with or without digital video alongside). As you can see, the difference between the two lies at the right side; the DVI-D plug has a single, wide flat pin, while the DVI-I plug has that same pin, but also four additional pins, two above and two below it. Those pins are used to carry the red, green, blue and horizontal sync (R,G,B and H) lines of an RGBHV analogue video signal (the vertical sync lies on another pin). If the receptacles on your devices don't have holes which will accept these four pins, then you have a DVI-D connection, which is all digital, no analogue. If the receptacles do have holes for these pins, then you need to know whether both the digital and the analogue modes are available on the DVI port--check your user's manual.

DVI-D Plug: DVI-I Plug:

Some devices simply use a DVI-I socket as an equivalent to a VGA socket; these devices do not send or receive digital signals, and the best way to connect them is through an adapter to a VGA cable or to a set of RGBHV cables; see our DVI Analogue Connection Options, below. Alternatively, a device with a DVI-I socket may be capable of sending or receiving digital DVI signals through that port, and if the devices on both ends of the cable are both using DVI digital signals, you'll want a DVI-D cable. If the question whether you're dealing with a digital or an analogue connection is confusing you, and you need further guidance on what sort of cable to use, see this article: What Kind of DVI Cable do I Need?

DVI-D Cables from AVLink, Inc. Our search for quality DVI-D cables that would work well in long runs led us to AVLink, Inc., a DVI cable producer offering both single and dual-link DVI-D cables in a range of lengths. DVI-D is, unfortunately, a rather badly-designed standard, and the decision of the Digital Display Working Group (designers of the DVI standard) to employ twisted-pair cable rather than coaxial cable to carry high-bitrate digital video without error correction resulted in severe problems with signal degradation over distance (a lesson which, alas, ought to have been well-learned by those who then carried the error forward in the HDMI standard). At a distance of only a few feet, any competently made DVI-D cable will do fine; but at long lengths, and high resolutions (the bitrate in DVI-D is tied to resolution) cable quality becomes a factor of critical importance; a poor cable will cause bit errors leading to "sparkles" on the display or even complete loss of signal. We've tested the AVLink DVI-D cables at 1080i and 720p resolutions, all the way out to 50 feet, and have observed no signal degradation at all.

Single Link or Dual Link?

We carry DVI-D cables both in single-link and dual-link configurations. The difference between the two is that the dual-link contains additional twisted pairs, and if both your source equipment and your display are set up to handle dual-link, the use of these additional pairs will lower the bitrate, increasing the effective bandwidth of the interface. However, as matters stand today, there are very few devices on the market which actually use the dual-link interface. Dual link won't hurt anything, but in most cases, it won't help either. Our single-link and dual-link cables also differ in external appearance; the single-link cables have a black jacket, with a gold-plated connector, while the dual-link cables have a white jacket and a nickel-plated connector. In some cases, the single-link cable will also be missing six pins from the middle of the 8x3 pin array, and this sometimes causes concern for customers; in fact, these pins are not connected to anything in a single-link DVI cable, so their presence or absence makes no difference.

DVI Analogue Connection Options:

We also carry several products designed for use with devices that use a DVI port as an input or output for a regular analogue RGBHV signal. Please be sure, before using these, that the DVI socket on your device is a DVI-I socket (that is, that it has sockets for the four analogue pins surrounding the ground pin, as shown above) and that the device is designed to accept or put out an analogue signal through its DVI port. If these conditions are not satisfied, these analogue connections will not work. If you're confused about whether you can use an analogue or a digital DVI connection, see the following article: What Kind of DVI Cable do I Need?

Our DVI analogue connection options include a small hardshell male DVI/female VGA adapter, DVI to VGA cables, DVI to Male BNC breakout cables, and short (one foot) DVI to Female BNC breakout adapters. For any length over ten feet, we recommend using the DVI to Female BNC breakout adapter, together with a full-sized set of RGBHV cables (available in our RGBHV department). Use of the breakout adapter for long runs will ensure the lowest possible signal loss by avoiding the use of miniature cable over significant distance.

As with all of our products, we offer a complete and unconditional return privilege. If for any reason you're not completely satisfied, just return the cables within 30 days and we'll refund your purchase price in full.

BJC Series-1 Belden Bonded-Pair HDMI Cables:

Our best; the only bonded-pair HDMI cable in the world.

BJC Series-F Belden Flexible HDMI Cables:

Stranded 26 AWG conductors, more flexible than Series-1

BJC Series-2 HDMI Cables:

(Chinese-made, 24 AWG)

DVI Single-Link Cables:

DVI Dual-Link Cables:

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