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This topic comprises 2 pages: 1 2
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Topic: "series 1" vs. "series 2"
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Stephen Furley
Film God
Posts: 3059
From: Coulsdon, Croydon, England
Registered: May 2002
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posted 07-27-2010 11:47 AM
quote: Steve Guttag
Not really...with 3G-SDI...there is sufficient bandwidth to run just 4 cables and get 4:4:4 4K...I trust coax cables MUCH more than UTP (Cat 5/6). I even trust it more than Fiber...which is where we will be going...also a means of moving high bandwidth content.
Are the newer digital projectors using 3G-SDI, or are they still using two links like the older ones. I was looking on the Kramer site for something unrelated, and they have several products for 3G-SDI now.
They're putting Cat 6 in the fefurbished area and the new build here at the moment and I don't like it. It's much stiffer than Cat 5e, and the fact that it's LSZH makes it even worse. The Cat 5e LSZO which we've been using for some years now isn't too bad. Cat 6 has larger minimum bend radius requirements than Cat 5e; they're having to use larger trunking, and special corner pieces to meet these requirements.
Cat 6a is even worse; I hope we never see the unshielded version, it's huge, about 9 mm in diameter, and strangely shaped to prevent cables laying neatly next to each other - necessary to reduce crosstalk. The shielded stuff is actually smaller than the unshielded. Most of it has a shield around each pair, and then another overall shield. I'd rather have fibre if we need that sort of bandwidth.
Most of our fibre is now OM-3 laser optimised stuff, that will handle 10G Base-SR if we need it to in future. Have very few problems with fibre, as long as it doesn't use MTRJ connectors, and we've just retired the only switch which did use those.
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Scott Norwood
Film God
Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99
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posted 07-27-2010 11:50 AM
What are people doing that requires cat 6 utp that won't work equally well with cat 5e utp?
And what are the reliability issues with utp cabling? For in-wall and server room installations, it's fine, as long as the 100-metre run-length limit is observed. As long as the cable is made properly and tested before installation, the only real weakness should be the RJ45 connector, but that is only really an issue if the connector is repeatedly inserted and removed. For a permanent install, I don't see this being a real problem. Yes, there is some really cheap cable out there that can be brittle or which has fewer twists for some pairs, but I am referring to quality cable from Belden or similar.
The only real win for fiber should be with long runs or in electrically noisy environments. The fiber "cable" itself is actually quite fragile.
(Note that my experience with this stuff is in IT/data center use, not cinema. Your mileage may vary, etc., etc.)
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Stephen Furley
Film God
Posts: 3059
From: Coulsdon, Croydon, England
Registered: May 2002
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posted 07-27-2010 01:41 PM
quote: Scott Norwood
What are people doing that requires cat 6 utp that won't work equally well with cat 5e utp?
Nothing that I'm aware of. Cat 5e is good for 100 m of 1000 Base-T, and anything else you're likely to put through it, analogue telephones, ISDN, Token Ring, RS-42, RS-485 etc., is less demanding. If you're wanting to use 10G Base-T then you need Cat. 6a, unless you're only running a short distance. Cat. 6 seems almost pointless, but many organisations insist on using it now. It's quite a bit more expensive than Cat. 5e, and they're installing tens of kilometres of the stuff in our building at the moment. I suppose that if you had a situation which was just marginal for Cat. 5e, overlength or in a very noisy environment, you might do better with Cat. 6.
quote: Scott Norwood
And what are the reliability issues with utp cabling? For in-wall and server room installations, it's fine, as long as the 100-metre run-length limit is observed. As long as the cable is made properly and tested before installation, the only real weakness should be the RJ45 connector, but that is only really an issue if the connector is repeatedly inserted and removed. For a permanent install, I don't see this being a real problem. Yes, there is some really cheap cable out there that can be brittle or which has fewer twists for some pairs, but I am referring to quality cable from Belden or similar.
Some pairs should have more twists than others; the cable's designed that way to reduce crosstalk between pairs.
quote: Scott Norwood
The only real win for fiber should be with long runs or in electrically noisy environments. The fiber "cable" itself is actually quite
Our LAN is copper from core switch to severs, fibre from core switches to edge switches and copper onwards from edge switch onwards. Our SAN is all copper, because it's all in one room, except for a couple of links to another building for backup purposes.
Our main building is a strange shape, and 100 m doesn't go far; many of our fibre runs are more than that. Some runs through an underground car park to another building, that was just within range for the OM-1 multimode that was installed there. We were using FSSI in those days. The other building has a totally different supply, not only does it have a separate substation to the main one, but the 33 kV substations feeding these substations are different. One building is well overvoltage, and the other, until a couple of weeks ago when a new HV feed was installed was well undervoltage. Goodness knows what the ground potential situation would be between these buildings.
Copper takes much more space than fibre; the 16 core fibre cables which we run to our comms rooms are not much larger than a single Cat. 6, and smaller than Cat.6a. There are about 20 of those fibre cables, and if we were to use copper then it would tak eight cat. 6 to replace each one. We have one 24 core fibre cable which is even thinner, it's almost exactly the same size as a Cat. 6. Many of our older switches only support Gigabit uplinks on fibre; the newer ones will take copper as well. No risk of mains Voltage finding it's way onto data cabling if cable are damaged by workmen etc. With multimode fibre it's easier to fault-find; shine a white test light down the fibre, and see if it comes out of the other end. (Usual warning about not looking into a fibre, or a fibre connector, unless you're sure what is on the other end).
Most cabling is pretty reliable if it's locked in a comms room away from users, but I would say that the fibre is more reliable than the copper, at least now that we've got rid of the few MTRJ connectors. Fibre is not that fragile, but I wouldn't want it to the desktop.
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