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I recently started a new position and upon investigation it appears all data drops from the floor first gets punched down on a 110 block, cross connected to another 110 block and then connects to a patch panel. I was horrified and surprised that this setup was even working. They are using un-shielded cross connect cables between the two 110 blocks.

I started searching the web and it appears that some shops consider this acceptable. I would think there would be cross talk issues up the wazoo. Am I wrong? Is this type of setup acceptable?

Frank Owen
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  • IANANE, but at $oldjob we had all the datacenter jacks going to one set of 110-blocks, another set of 110-blocks for the switch-ports (~240 of 'em), and patch-cables linking the two. We had GigE speeds throughout and worked really well. No idea if that is best-practice, though. – sysadmin1138 May 25 '11 at 00:25

2 Answers2

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UTP cable is the most common cabling used in computer networking.

When you say they're using unshielded cable I assume you mean that they're using twisted pair cable enclosed in an unshielded sheath. Is that the case? If so, then I think you'll be fine and you'll find the same implementation with most patch panels.

In addition, crosstalk is usually a factor related to the twist, not the shielding, unless you have many unshielded pairs running parallel to each other in very close proximity. The twist that's manufactured into network cabling is designed to minimize crosstalk.

joeqwerty
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  • Joe: Thank you for the information. What you posted makes perfect sense and I am not sure why I thought a magic plastic jacket would stop interference. The cable we are using is not shielded or in a sheath, it is just plain ole Cat5 cross connected cable (I looked at the label). I was looking around the web when I found this: http://www.siemon.com/e-catalog/ECAT_GI_page.aspx?GI_ID=mpc_category-6-cross-connect-wire . Shouldn't this cable allow for longer runs then 5 meters? – Frank Owen May 28 '11 at 05:47
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What you are describing is actually an extremely common way of terminating locations on the floor to a central point. You will find that many datacenters and organizations that tend to adhere to cleaner and flexible structured cabling models will do exactly this. When I worked for a major Electrical Contractor, most of our structured cabling installations were exactly as you describe. In fact, while you probably do not want to take this approach with 10GbE, this will work just fine with 1GbE over CAT5e and runs shorter than about 400 feet. I think the term acceptable implies that this model is in some ways sub-par, which could not be further from the truth. The art of structured cabling is rooted with this design, and while it could be done poorly, no doubt, when done right, it is an extremely flexible, robust and datacenter proven model. I have seen some really poorly done 110 panels, but when done right, it will last for many, many years, and is easy to maintain.

slashdot
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  • Thank you for the insight. I had no idea this was used but it makes perfect sense now. The room this is used in is about 10x15 but I can see the benefits if done properly. When you setup something like this in the past, what cable did you use? In your opinion, would I be better off with this, http://www.siemon.com/e-catalog/ECAT_GI_page.aspx?GI_ID=mpc_category-6-cross-connect-wire or this http://www.siemon.com/e-catalog/ECAT_GI_page.aspx?GI_ID=mpc_category-5e-cross-connect-wire ? – Frank Owen May 28 '11 at 05:48