Straight-Through, Crossover, or Rollover?

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G2startracker

I built my home from the ground up and ran Cat-5, but haven't come up with a plan for the patch panel at all. I would like to hook up the kid's computer for the moment. I installed the two RJ-45 terminators in each room bothwith Orange on the left and Brown on the right. If I plug one into the modem and the other into the 2nd computer how should the wires be connected inthe attic? Plus, will it hurt anything to just start trying blindly? I've been reading and thinking and just seem to get more and more confused.

It looks like I should mirror the wires as in Rollover and leave the terminators the way they are.
 
G2startracker said:
I built my home from the ground up and ran Cat-5, but haven't come up with a plan for the patch panel at all. I would like to hook up the kid's computer for the moment. I installed the two RJ-45 terminators in each room both with Orange on the left and Brown on the right. If I plug one into the modem and the other into the 2nd computer how should the wires be connected in the attic? Plus, will it hurt anything to just start trying blindly? I've been reading and thinking and just seem to get more and more confused.

It looks like I should mirror the wires as in Rollover and leave the terminators the way they are.
Click to expand...

I'm not sure I've interpreted your question correctly,
so it's likely this is entirely the wrong answer. Anyway,
here goes...

*******

See the "Auto-MDIX" section at the end of this article.

http://en.wikipedia.org/wiki/Mdix

I use a Netgear switch, as a "patch panel" for my
computers. The nice thing about GbE equipment, is it
is highly likely to work right out of the box. Only
botching the wiring of the pairs, could screw it up.
And some NICs even have diagnostic capability - my Marvell
NIC chip, can detect shorts or opens, and can tell you
which pair isn't working. (It's like it uses TDR to
do that, and can tell what the impedance of the cable
is, as well as the time-of-flight length.)

http://www.downloads.netgear.com/files/GDC/GS608/GS605_608_datasheet_13May2004.pdf

"Every port automatically senses the right speed and full/half duplex mode,
and Auto Uplink technology automatically adjusts for straight-through or
crossover cables"

If you wish to connect two computers directly to one another,
and the computers have GbE ports on them, then the same "auto"
function exists. You can use straight or crossover, and the
PHY on the NIC figures it out. As far as I know, it's all done
in hardware (typically). At work, the PHY we used would negotiate
the network rate properly, even when the CPU was crashed :-)

I only have one crossover cable in the house, and I think
I lost it :-) That's how unimportant stocking both cable
types has become.

I still need to use that crossover (and go find it), if I
need to connect two ten year old computers directly
to one another, the ones that don't do "auto anything".
Then the crossover pattern is needed. But since most
of my wiring will be using my switch and router (ports
on both, depending on need), I can usually wiggle out
of needing special cables.

Paul
 
Paul said:
I still need to use that crossover (and go find it), if I
need to connect two ten year old computers directly
to one another, the ones that don't do "auto anything".
Then the crossover pattern is needed. But since most
of my wiring will be using my switch and router (ports
on both, depending on need), I can usually wiggle out
of needing special cables.
Click to expand...

I find that it's easier to find a spare switch kicking around than a
crossover cable.
 
I built my home from the ground up and ran Cat-5, but haven't come up with a plan for the patch panel at all. I would like to hook up the kid's computer for the moment. I installed the two RJ-45 terminators in each room both with Orange on the left and Brown on the right. If I plug one into the modem and the other into the 2nd computer how should the wires be connected in the attic? Plus, will it hurt anything to just start trying blindly? I've been reading and thinking and just seem to get more and more confused.

It looks like I should mirror the wires as in Rollover and leave the terminators the way they are.
Click to expand...

If you get it wrong it just doesn't work, nothing is harmed.

With modern gear it probably works even if you do get it backwards
anyway.
 
I admit I clicked to see what this thread was about for all the wrong
reasons. I have a dirty mind.
 
In the last episode of <[email protected]>,
Timothy Daniels said:
I believe the concept of "patch panel" went out with analog telephones/66-blocks and coaxial TV
cables/splitters.
These days you'd be using routers/switches, either wired or wireless.
Click to expand...

If you're doing a professionally wired system, you'll still use a patch
panel, and then connect those ports to the switch as needed.
As for the CAT-5 cables, I
assume you ran
solid wire cable to the RJ45 wall terminals for reliable punch-down connection, but for the jumper
cables (which
may get moved around a lot) professional cablers recommend industrially manufactured jumpers with
stranded wire.
Stranded wire is harder to connect properly to the plugs and with uniformity from cable to cable, so
for big jobs,
even they just go out and buy them pre-cut.
Click to expand...

This is a big part of why you use a patch panel; You run solid cable
from a wall jacks around the house to one central patch panel, and wire
the patch panel to the switch port with pre-cut stranded.
 
G2startracker said:
I built my home from the ground up and ran Cat-5, but haven't come up with
a plan for the patch panel at all. I would like to hook up the kid's
computer for the moment. I installed the two RJ-45 terminators in each
room both with Orange on the left and Brown on the right. If I plug one
into the modem and the other into the 2nd computer how should the wires be
connected in the attic? Plus, will it hurt anything to just start trying
blindly? I've been reading and thinking and just seem to get more and more
confused.

It looks like I should mirror the wires as in Rollover and leave the
terminators the way they are.
Click to expand...

Along with what everyone else has already posted, I'd like to add that if
you're using gigabyte NIC's, you may not get full speed with them because of
the CAT5. Gigabyte requires CAT5e or CAT6 for full speed. If the NIC's are
set to "auto-negotiate", then you'll most likely get a 100MB throughput. I
have seen more than one GB adapter that would not connect at all or would
connect intermittently with CAT5 cabling.
 
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