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RE: [KAT5] Off-the-Wall Question...

Hi Tom,

Tim got in before me LOL

The 2 unused pairs in an Ethernet cable are NOT grounded

Ideally although CAT5 can be used for mulitple types of service is should
considered a single service cable at all times to prevent possible problems
from mispatching.

Having said that, the adapters that Tim mentioned are specifically intended
overcome lack of infrastructure. The difference between the various types
to present the unused pairs on the correct pins of the sockets.

Ethernet uses the green and orange pairs, a dual ethernet version takes the
blue and brown pairs and on the second socket presents them on the pins for
the orange and blue.

BTW. Just to keep on topic... KAT5 uses all 4 pairs so no sharing possible



> I have a wierd Ethernet/telephony wiring question, and don't
> know who else to ask, so thought there might be enough
> expertise on this mailing list to get a basic sense of an answer.
>  From what I've been able to read, the expectation is that
> the 4 unused leads in a standard Ethernet cable are supposed
> to be grounded, so it wouldn't surprise me if I get some
> cross-talk or loss of signal strength, but I wanted to know
> if anyone on this e-mail alias could either tell me that my
> risks are low so go ahead, or that I'm a complete idiot and
> trying to run the two different signal types through one
> cable is a fool's errand.
> I would even be interested to hear that, since pairs in an
> Ethernet cable are twisted, if I run the Ethernet signal
> through two twisted pairs, and the phone signal through one
> or two of the other two twisted pairs (admitting that, for
> the length of the run between the two cabinets, my cabling is
> completely non-standard), I reduce the chances of cross-talk
> and/or signal loss.
> I'll also be interested in hearing that I could get away with
> this if I stick to 10/100, but all bets are off for 1G.
> Thanks,
> Tom


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