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I'm re-wiring a building and want to get the best cable possible laid - it required re-plastering to make a change to the cables and the cables will be there for the next 10 - 20 years.

Currently there appears to be cat 7a cable available but not too much in the way of cat 7a connectors. Also - I won't be using 40Gig hardware in the near future.

So, my question: is it possible to use cat 6a connectors / patch panels with cat 7a cable and get the same performance as I would had I used cat 6a cable? Are there any gotchas in trying to do this?

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2 Answers 2

up vote 5 down vote accepted

Generally speaking, if you mix "better" equipment with "lesser" one, your performance will be somewhere in between them, possibly even better than when using only lesser equipment: CAT6 cabling will not bump your speed up if you have 100 Mbit switches, but CAT7a cable could give you better EM shielding than CAT6a and thus reduce spurious network errors.

So, yes: there is no incompatibility between CAT7a cable and CAT6a connectors, and although you will not achieve CAT7a certification without using both of them (and connecting them accordingly to standards and best practices), you can safely mix them, it could even benefit your overall networking experience, and you'll be able to simply replace the connectors later without having to re-cable everything (assuming it won't be already time to jump to CAT9g cabling, of course).

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That was what I was hoping to hear. I'll push the installer to use 7a cable with a signoff on 6a performance. – Mr. Flibble Sep 12 '12 at 15:46

Ultimately the 'Cat-level' is something that your cablers test and sign off against, I'd leave it to them to do using whatever parts and testing method they like, they're the ones that's sign and support it so just let them do their job knowing you'll kick them hard if things fail. If you were planning on doing it yourselves/internally I think you've either got a long job ahead of you or you're not going really get to a position of knowing it's Cat6/7 compliant sorry.

That said I wouldn't realistically expect the cabling to last to that level for more than 10 years, there's inherent longterm degradation of both connectors and cables that will increase attenuation over that period - even with most fibres. I'd bank on no more than 10 years to be honest.

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OK - I'm getting it professionally installed. I could leave them to it and have them use Cat 6a cable, but given that most of the expense is in the installation it seems wasteful to me to put in Cat 6a cable when Cat 7a is available. I do not expect any better performance by using 7a cable -- the plan is that down the road I can replace the connectors with 7a when they are available and I have the need for such speed. – Mr. Flibble Sep 12 '12 at 15:44
I see, thanks for the clarification, in that case obviously 7a has 4 pairs that could be wired to a Cat 6a connectors, though it depends if you're using the duplex cable type or not, in which case it's just two of the simplex cables bound together, so you could the same. Basically yes, do that, though I'd be more tempted to run OM4 fibre myself. – Chopper3 Sep 12 '12 at 15:52
Thank you Chopper3! Both you and Massimo have perfectly acceptable answers - Massimo needs the points more tho :} – Mr. Flibble Sep 12 '12 at 15:59

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