I get the very rare opportunity to quasi-correct Steve Terry on something
E1.11 actually says nothing about cabling. All cabling requirements were moved to seperate documents. Those are E1.27-1 for
Portable Cables and E1.27-2 for Permanently Installed Cables. Available for
purchase from:
ESTA Foundation - Publications - About Publications, Browse & Purchase
What E1.11 does specify are
connector types that are allowed. The use of the 3-pin
XLR is specifically DISALLOWED. End of discussion.
Here is what E1.27-1 says on the cable construction:
ANSI E1.27-1 - 2006 (R2011) also states that it is allowed to
build portable cables that contain only the primary data pair provided they are marked with "Single pair" or "1-pair" and also marked with a violet band at least 1/2" wide within 2 inches of this marking. Of course, you still can NOT use the 3-pin
XLR. You MUST use the 5-pin
XLR (for what I hope are obvious reasons!)
So, that's the end of what the standards say. In Europe it is very common to
build single pair
portable cables which is why this is included in the standard. In the US most
portable cables are wired for all 5 pins. Many(most?) permanent installs do not have all 5 pins wired. Back in my day at
ETC, standard procedure was NOT to connect pins 4/5 in the wall plates in installs. I do not know what
current practice on their installs is.
In reality, aside from a few legacy proprietary uses pins 4/5 are not being used for anything. They are generally a landmine of incompatabilities for the few that tried using them.
In regards to shielding, I believe
portable cables should all be shielded, but according to Steve Lampen from Belden at the speeds we are running for
DMX512, the shielding provides relatively little noise immunity compared to the pair twisting, which is what provides the most immunity. This is another reason it is important to use proper data cables and not audio cables. Audio cables may be well shielded, but they don't have the proper twisting to provide good noise immunity for
DMX512 (not to mention the high
capacitance issue!).