Shielded Cat5e for Gigabit Ethernet

We're bring in a machine (IBM) and they are insisting on shieleded cable for the Gig ethernet connections. Their argument is for FCC emination requirements. We will be connecting to Cisco 65xx 10/100/1000 modules.

My question:

  1. Doesn't STP have a higher impeadance (150 ohm) vs 100 for UTP. If so, does the electronics adjust to it automatically.

  1. Does STP usually come as solid core? We're going to put in massive amounts of this patch cable in and plumbing solid core into a 6509 with stiff solid core patch cables will be a pain.

We've been happily putting in gobs of Cat5e UTP for other Gig connections with no problem, IBM just loves to go "by the book".

I've scanned Cisco's site to see what they had to say, nada.

Thanks for any replies.

Rot 13 to get my email address.


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Perhaps they mean ScTP, which is Screened Twisted Pair (basically a foil or braided screen). I often see STP confused for ScTP.

150 ohm STP is token ring cabling and is not compatible with gigabit ethernet.

Just about any UTP component is available in an ScTP version, but a lot more expensive.

I kind of doubt the need for it in most cases, as 1000baseT was designed for UTP.

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They may be talking about Gigabit Token Ring. I don't really know about its media preferences as the application almost disappeared from the radars here, but I doubt it specifies a shielded cable as THE ONLY option.

In case of Ethernet you can continue happily install unshielded CAT5E as it was designed for 1000BASE-T in cooperation with IEEE. I can see someone insisting on installing CAT6 instead of CAT5E for just in case, but screened instead of UTP? It must be someone's mistake or misunderstanding. Otherwise ask whoever you are talking to at IBM to produce the document that specifically says ScTP is required (or any other type of shielded/screened cable to that matter). I don't think such document exist, and they are just adding a huge (and unjustifiable) burden on the customer's budget.

BTW, if such document does exist, and they can produce it at your request, can you post a reference here, a Web page or at least the name of the document?

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Well, if they're the standard Cisco 10/100/1000 cards for a 65xx, they're not going to be Gigabit Token Ring. So that is out. I think some one is just tring to sell you on shielded/screened cable. I've had one manufacture trying to sell me on FTP to 'truly' be able to run

10Gig, not 1gig. And of course the already pointed out that 1gig should run on any Cat5e. I've not looked at Sc/S/FTP patch cords, but I would assume that they would be stranded. JT
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