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Looking at taking over management of an old network that was done in 2004. Surprisingly, for the time, it is category 6 cable. About 200 ports in each of 5 IDFs, all running PoE.

But I'm worried the cross-connects are unusable for a modern network. The switches are connected to standard patch panels. The cable from there is terminated into a punch down block (BIX.) The cabling coming in from the edge is also terminated into punch down blocks. The connection between the two punch down blocks is made with UTP cables of up to a metre long that have had the jacket removed.

So, can that setup handle gigabit speeds? I'm inclined to say no, but maybe I am just being overly cautious.

Photo of the cross-connects in question

A bigger version of the photo.

  • Can you post a bigger picture? – Ward Mar 18 '16 at 17:06
  • I'm on the app, all it will let me do is upload, doesn't ask for a size. It's just UTP without the jacket. – miken32 Mar 18 '16 at 17:12
  • Without the jacket it sure seems like the the pairs would do a good job of maintaining the appropriate twists. Each pair is twisted, at a different frequency, and all 4 pairs are twisted around each other all to minimize cross-talk between the pairs. So, can that setup handle gigabit speeds? - This is one of those things where I would want to rent/borrow/buy a cable-tester (w/TDR) and run some tests and see if it tests out to spec. – Zoredache Mar 18 '16 at 17:37
  • BTW I can find lots of articles on the internet suggesting a suggested jacket removal length of 2-3", but there don't seem to be hard rules. siemon.com/us/white_papers/99-07-05-twistpairprep.asp Though the official TIA specs are behind paywalls. global.ihs.com/doc_detail.cfm?item_s_key=00378460 – Zoredache Mar 18 '16 at 17:42
  • @miken32: I've deleted my answer. I had always assumed that the jacket was there simply to act as a protective cover and to maintain the cable pair twists, but after doing some more research it appears that it can in fact have a bearing on impedance, attenuation and far-end crosstalk. – joeqwerty Mar 18 '16 at 17:50
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It's not possible to tell for certain from a picture. Obviously the best thing to do would be to get or borrow (since they're expensive) a tester and do some end-to-end testing to find out for certain if the whole thing is up to Cat6 spec.

There are Cat6 spec punch-down blocks available, so the first thing to check is to see if that's what you've got.

I asked in a comment for a bigger picture so that it would be possible to see the condition of the unjacketed cables that connect the punch-down blocks - how much is untwisted at each end, how do the pairs look, etc. I'd be looking for:

  • whether the individual pairs of the patch cables are still properly twisted
  • if each cable is still "together" (i.e. all 4 pairs are close together)
  • no sharp kinks in the cables

If the patch connections are Cat6 or 5e cable that's been unjacketed and if the cables are in good shape and if the punch-down connections are good (not too mangled in the untwisting) and if it's Cat6 blocks... then you might get gigabit out of it.

  • I'd be concerned about relying on a cable test versus actual use with dozens of cables interacting. The punch downs are all cat 6 certified. The pairs all have their twist to within a centimetre or so of the block. – miken32 Mar 18 '16 at 17:58
  • I've edited to include a link to a bigger photo. – miken32 Mar 18 '16 at 18:46
  • Cool! It's interesting to see the details... Almost all of the patches look to me like the pairs and the "cables" are in good shape (the cables still look like cables even though they don't have jackets. If it were me, and I did some simple tests and found I could get end-to-end 1Gig connections, I'd probably trust it. It looks like there are a few loose pairs on the right-hand side, just above the gap in the middle. – Ward Mar 18 '16 at 19:03

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