Network crossover cable markings

Hi,

I got bit, today, by an "unmarked", store-bought patch cord that was, in fact, a crossover cable. After a fair bit of time wondering why "nothing works", I went back to basics and found the problem with a cable tester.

And, immediately informed the lady from whom I'd received the cable that it was a "special" cable and hacked together a (paper) label to try to help others avoid getting bit by the same unexpected problem!

So, the question is, how do you mark cables like these so folks can quickly recognize that they are dealing with something "special"? (my cables are all labeled with *lengths* as I only keep "straight through" cables and rely on a little inline adapter to "fabricate" xover cables -- out of regular cables -- when needed)

Thx,

--don

Reply to
Don Y
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most modern NICs, HUBs, switches etc. don't care if the cable is crossed

-Lasse

Reply to
Lasse Langwadt Christensen

Don Y prodded the keyboard

You don't bother ! Just put the ends together and compare them !

--
Best Regards: 
                       Baron.
Reply to
Baron

Must be a old piece of equipment. All the new stuff I've seen will auto mdi-x. What I have seen is usually cross over cables have a green jacket but it is not a standard. At a ppoe we used green - x over red - wan to fw yellow - 10/100/1000 blue - phones other - 10/100

Use a label maker and put a big X on each end of the cable.

--
Chisolm 
Republic of Texas
Reply to
Joe Chisolm

Yup. IIRC, Auto MDX wasn't "mandated" until Gb. I still see a few hundred

10/100 switches coming out of businesses every week ("discards") so assume there is still a fair bit of old kit "in use". Either having a crosswired "uplink" port, one port present in normal and crossed configurations ("use only one"), a crossover "pushbutton", etc.

I've got all sorts of different colored cables so really only use color to help differentiate among N cables *at* the switch. The cable that tripped me up was orange.

I labeled each end "CROSSOVER" out of fear someone would think 'X' meant something else ("bad/broken", "X" of "Z", etc.). No guarantee they'll *read* it but at least *I* won't get tripped up by it!

(That's actually the second oddball cable that I've encountered, there. I think they just figure any 8P8C connector is "computer" and never consider that the wires *might* be arranged differently "inside"!)

Reply to
Don Y

Three approaches:

(1) only make/buy crossover cables in a hideous color (violet, or maybe red or orange) and pepper your logbooks/instructions/checksheets with references to the color and 'crossover' type. This never works.

(2) heat-shrink a contrasting color band near each connector, preferably with 'crossover' hot-stamped into it. Has to be done before crimping the connectors on, generally.

(3) get some of those flag-equipped wireties, and affix a label near each end (this also helps figuring out which DC adapter goes to which VeryImportantItem).

But, I generally fall back on the memorized "orange/white, orange, green/white, blue, blue/white, green, brown/white, brown" sequence and if this isn't seen on both ends, it's a crossover cable. This requires, mainly, good light, a lens, and some memory or a cheatsheet, so ALWAYS have those available when wiring.

Reply to
whit3rd

Agreed. What happens when you're given a nice 100 ft length of CAT6 that just happens to bear the "wrong color jacket"? "No thanks! I'm partial to yellow..."

I use labeling tape (e.g., the cheap "Brother" labelers) placing the *length* of the label along the cable which has the short height just enough to wrap most of the way around a ~1/4" dia cable. Then, some heavy duty cellophane "packing tape" to cover it and prevent the edges from lifting up during use.

(Unfortunately, this makes that section of the cable pretty rigid)

Ick! They make it damn near impossible to *pull* cable!

As for wall warts, I use the same labeling tape and affix an appropriate label to the side of each wall wart/brick. Much easier for my aging eyes to read

18 point type than 6 pt! :>

Yeah, those things are rarely all available. I have a small pocket magnifier (about the size of a loupe but a complex lens for greater magnification) but it still relies on having enough ambient light available. If you're under someone's desk, that's not always the case! A lot of the 8P8C connector shells are semi-opaque or *dark* and recognizing colors (on very small conductors) through them is tedious at best. That's why I carry a cable tester when doing this sort of work (I don't have to wonder if that's a green tracer or a blue tracer on that white wire...)

I was hoping there was some universal convention that was followed that I could simply adopt.

Of course, the mistake was making the cables straight through in the first place! ALL should have been crossover cables! Connect PC to PC? use crossover cable Connect PC to (my version of) switch? use crossover cable Connect switch to switch? use crossover cable Then, the only problem you would have is F-F adapters that "splice" (lengthen) cables -- but, even those could "crossover" to ensure that the resulting M-M cable is *still* a crossover cable!

Reply to
Don Y

That means crossed two times? ;-)

--
Reinhardt
Reply to
rbehm

Agreed. There was a kinda-sorta standard for a while, at least at retail, that crossovers were yellow, but it's not reliable.

If you look around a little you can find 3:1 heatshrink, which is just about enough to fit over an RJ45/8P8C connector and still shrink down well on the cable.

In huge quantities, you can get "xover" molded into or stamped on the boots.

As has been mentioned, OK if you never need to snake/pull the cable anywhere. (Which, for shorter cables in a lab environment, is actually true in a lot of cases.)

Or maybe one of those cable continuity testers with a SP8T switch on one end and 8 LEDs on the other. Or, build yourself a box with two jacks and your favorite microcontroller in it, with "regular", "crossover", and "oddball" LEDs.

Matt Roberds

Reply to
mroberds

Over here manufactured crossovers are always purple, but that may be because most of NZ gets its cables from dynAmix.

--
umop apisdn
Reply to
Jasen Betts

I use an old Navitek cable tester:

It's pretty clever. It will check continuity on pairs, identify which of 8 "cables under test" you are currently probing, ping a host, guesstimate cable length, etc. Tough on batteries (older technology). But, handy when setting up a site!

I think newer versions will actually tell if you've swapped color pairs (yet still have the "right" overall continuity).

Reply to
Don Y

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