04.09.15

HD and Beyond: The Cable is King, Long Live the Cable

We live in an increasingly wireless world.

Wireless telephone, wireless internet and now wireless power; to the point where the UK Government are about to embark on a scheme to trial motorways that charge your Plug-in-Hybrid-Electric-Vehicle as you drive along them.

HDMI-Black-Platinum-299x400For me though, nothing beats “plugging in”. Plugging a cable, a physical item, for a physical connection; cannot be beaten for reliability and stability. The near on assurance of function, in the very least, a better chance of function at the first attempt. I plug my car in at the charge point, it works. Am I comfortable with the idea that the required current and/or voltages are instead flowing across the air up through the tarmac to my batteries like an electric toothbrush? No, not really. When I’m at the office, I plug into the hard-wired computer network. The wireless is sometimes temperamental and I know the cable is quicker at moving data around in practice. In amongst all this is wireless video and wireless HDMI transmission devices.

In years gone by, these things made me cringe at their very mention. Where did the Sony TV models with the wireless input boxes go? Even with the improvements they’ve gone through, it still strikes fear into my heart each time someone suggests we stock such an item on the shelves of HDanywhere. If wireless HDMI transmission had been great, maybe even brilliant and something that the consumer could see work reliably over time, we’d all be selling wireless HDMI distribution systems within the CI community.

As it is, the industry uses internationally recognised category network cable and hardware. Relatively cheap, readily available and widely used enough that the basic skills to install it are not hard to find or learn. The cabled install is still king when it comes to HDMI. But there’s a problem out there…and it’s going to get worse.

When it comes to HDMI, the technology is very forgiving. Bit Error Correction (BER in most sinks, i.e., AVRs and TVs) is amazingly good at recovering your ones and zeros should they be horribly mis-shaped by a poorly made HDMI lead. I’ve seen some truly terrible waveforms on HDMI leads, unrecognisable to the eye, that still give an image on the TV. Those white pixels in an image (sparkling) is the first sign that your signal is finally too poor for the TV to “guess” or correct where a one or a zero should be when it’s not there in the waveform. When it comes to HDMI transmission over category cable (in a matrix or extenders, for example), the technology that has become most widely used is HDBaseT from Valens.

Again, by its very nature, HDBaseT is extremely forgiving. Massively forgiving. What this means is that a poorly installed category network cable, with poor HDMI cables can still give you a working result. It’s possible to install category network cable well enough for a bandwidth of signal like 1080p, but will fall down with the arrival of higher bandwidth signals from HDMI 2.x and the 4K / HDR it brings with it. Similarly, all those badly made HDMI cables (not necessarily those 99p specials) that worked for 1080p, are now about to fall over for 4K and HDMI 2.x. Despite the HDMI lead specification not changing since day dot, not all HDMI leads were manufactured equal.

The tech team at HDanywhere, myself included, have made an increasing number of site visits recently to places where the installed category network cable or poor HDMI leads have been the reason for the onsite woes. We’ve seen twisted pairs stripped before going into the back of a socket. Installed by a UK-wide, well known, electrical contractors. We’ve seen twisted pairs hanging out of the back of RJ45 plugs and cables crushed into back boxes so hard the cores have snapped. We’ve removed HDMI leads so thin they can’t carry 720p and leads found in the bottom of a box employed (regardless of why they might have ended up there in the first place).

During troubleshooting, we’ll ask if the cable has been tested. A continuity test is not enough. The amount of times I’ve been told this qualifies as “tested” cable is becoming too scary to count. When our basic fluke tester is more than most CIs carry in their tool kit, that’s frightening. Without a specific tester, you can’t easily check a HDMI cable, but you can make informed choices when buying the leads in the first instance. Look out for new THX-certified cables appearing on the market, these cables have been through enough for you to know they’ll work for all HDMI 2.x brings. Infrastructure is the backbone of any project. The cabling infrastructure of a custom installation project is the very arteries, veins and nerves that carry all the information around and about to make things work. If this infrastructure is poorly conceived or poorly executed, then the overall system can be stunted.

With HDMI, this is the delivery mechanism for the images and audio the end user sees. The most visible part of any CI system. Everything else can work, but if the rugby isn’t there on a Sunday afternoon, the support call will be made. Anyone who tells you it’s ok to just “chuck in” some Cat-6 and terminate it is sending out the wrong message and is, bluntly, not helping those they advise or themselves in the long run.

Whilst we have a technology and product that will fix most of the ills in a poorly installed infrastructure, it doesn’t make sense to rely on that. The bad practice in the installation of category network cable is something we all need to address. I have no formal training in the installation of network cable. When I found an infrastructure specialist who really knows how it should be done, it went to show just how little I knew and how wide the field really is. Custom integrators either need to educate and embrace, or understand the value of having a specialist install it right for them. Having a certified infrastructure on which to connect any system should mean an easier time of commissioning and the real chance of some (of that most dirty of words) future-proofing.

Daniel Adams is the Director of Technical at HDanywhere.