Proggieus, I can't agree more. It has never ceased to amaze me how many people in this industry never dig past the surface of what they are doing. Sometimes "why?" is a very important question.

Back on topic, this would be what introduces the concept of skew when using standard CAT5, CAT6, etc. in AV applications and why there is UTP that is specifically designed for AV use, such AV UTP by Extron, and Nano-skew by Belden. It is basically CAT5e, but with a standardization of the twist rate between pairs.

It also says right on it, "not recommended for data applications."

I've also kind of thought that that defeated the purpose of AV UTP distribution in the first place, beyond distance issues. The "promise" when the stuff first came out was that you could use one cable for everything or just spec a bunch of CAT5e runs to the tel/data contractor on a union job and just come in and put the widgets on each end, or as much as the AV manufacturers say (to quote George Feldstein at his last major speaking engagement) "I would prefer that AV dealers become IT dealers rather than the other way around." and to some extent believe it, they don't love the idea of lowering the barrier to entry by making all the cable types and terminations the same and using a standard that is the basis of a similar and much larger industry. The more UTP based products become available, the more IT, tel/data companies start entering the AV world, the more UTP based products get sold and so on and so on.

Maybe this is good for the industry, maybe it isn't, but knowing that there is still a difference between what you want in an AV UTP Cable and what you want in a data UTP cable is a great example of the nuances we deal with on a daily basis.

To answer the question more specifically, to the best of my knowledge there is a standard for minimum twist rate, but none for the differences in twist rates between pairs or which pairs where more tightly twisted than other. In the early days of AV UTP transmission, you'd buy a preterminated cable of a certain length and it would come with 5 coax cables, the length of which varied to compensate for the skew in the UTP cable, or you could deal with it in the field. Not exactly the cleanest solution. Today there are active devices that can provide the necessary delay compensation in a box, either standalone or integrated with the receiver. If it was a standard, then the skew would be consistent and predictable by length of cable and you would have to adjust each video component individually, you'd just set it by length.