Talk:Ethernet crossover cable

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[edit] Redirected from "Ethernet Cable?"

What on earth? Of all articles on ethernet, why has this one(on just one type of cable) been nominated to receive all traffic from the aforementioned query? 24.166.7.167 00:31, 29 January 2007 (UTC)sudo


[edit] Crossover for 1000Base-T

What is the right crossover for 1000Base-T? Cisco says (Figures B-2 and B-3) that crossover is same as for 100Base-T.. `a5b 16:05, 17 January 2007 (UTC)

It should be the same, since the cabling for 1000Base-T is compatible with Fast Ethernet devices. But since most devices that are 1000Base-t have automatic MDI/MDIX detection, this doesn't usually matter. --Leonardo Horovitz 20:03, 17 January 2007 (UTC)

[edit] Needs a lot of work

This is mostly yanked from the old TIA-568A/B article, although it didn't fit very well there. This could use some cleanup as it now lives alone. The first sentence could make a good introduction if it were simplified (without specific references to standards) and expanded to mention what a crossover cable is used for.

I've tried to do so. Other than that, article looks good from a wikification standpoint. Wikified as part of the Wikification wikiproject! JubalHarshaw 19:20, 2 October 2006 (UTC)

[edit] Picture with wrong cabling

The first picture "A Crossover Cable suitable for use with 100baseT4." seems to be in error with its cabling.

The connector on the right shows:

GreenWhite - Green - OrangeWhite - BrownWhite - Brown - Orange - Blue - BlueWhite

The correct order would be:

GreenWhite - Green - OrangeWhie - Brown - BrownWhite - Orange - BlueWhite - Blue

So the creator of this cable switched the right pairs, but also the polarity of the first and fourth pair, which he should not.

-- (Unsigned comment by User:Treczoks)

As mentioned in the article, Gigabit Ethernet requires those pairs to be swapped as well. So, for 1000BASE-T the picture is indeed correct.
-- Tjohns ✎ 01:27, 2 May 2006 (UTC)
I have been preparing a quick reference card to attach to my tools. All the references that swap all 4 pairs, that I have found, show the first sequence to be the norm (Brown - Orange - Blue). HTH. —The preceding unsigned comment was added by 189.165.26.128 (talk) 17:26, 31 December 2006 (UTC).

There is something missing in the diagram labeled "Compare crossover cable pinout with standard pinout.". It just shows the T568A pinout, nothing about crossover cable.

-- Dantams 11:34, 29 December 2006 (UTC)

You are right. I complained about this some time ago, but none paid attention. A crossover cable is a cable that in one end is T568A and in the other end is T568B. A cable with any of those standards in both ends is a regular cable. --Leonardo Horovitz 18:29, 30 December 2006 (UTC)

[edit] Rollover cable?

Is there anything like a rollover cable? I stumbled across the term, and was surprised I haven't heard over it before. May be its worth an article, together with straight through cable me think. —Preceding unsigned comment added by Wk muriithi (talk • contribs) 09:50, 15 May 2006 (UTC)

indeed, such a thing exists.  It is commonly used for telephony, where the wiring order is exactly reversed at the other end of the cable.  On the other hand, Ethernet patch cables use a straight-through scheme; if you place the connectors side-by-side, you'll see that the wire color sequence is the same at both ends. —QuicksilverT @ 01:39, 14 December 2006 (UTC)
The Cisco web site has details. HTH —The preceding unsigned comment was added by 189.165.26.128 (talk) 17:26, 31 December 2006 (UTC).

[edit] Removing the "manual" part (networks created using crossover cables)

I believe the section about setting up a network connection shouldn't be here. Wikipedia is not supposed to be a user manual, only a source of information and reference.--Lenilucho 03:03, 24 September 2006 (UTC)

I don't really view it as a manual, as it lacks steps and directions. It just shows how the configuration looks for any generic crossover cable setup, and no more. Could it be re-written to be more "article-like"? I view this section as both a source of information and a reference. (Can you justify that it is not?) How else would you learn how to configure an ethernet crossover network? There is no better way to show this than to than to show an example. +mwtoews 14:54, 25 September 2006 (UTC)
P.S., I do share your opinion with some other articles, such as Screenshot, or even worse where a programming language is involved with examples etc., which are hardly encyclopedia material. They're useful, but I have no clue where else they would be appropriate. +mwtoews 14:58, 25 September 2006 (UTC)
Isn't the job of an "encyclopedia" to provide information and knowledge? If, (for example), I was writing an article on classes, class inheritance, or operator overloading in C++ or C#, it would be extremely germane to include code-based examples of what this means. Otherwise, how do you get your point across? Likewise, an article discussing painting, (as in art-painting, or even room-painting), or plastering a wall or ceiling, could effectively use pictures/photographs to make the explanation succinct and more easily understood in the context of the article. Jharris1993 04:33, 14 March 2007 (UTC)
Are you referring to section "Networks created using crossover cables"? What section are you referring to? Logictheo 16:40, 5 October 2006 (UTC)
Yes, I am referring to that part. At the time when I wrote that, it looked much more like an instructions manual.--Leonardo Horovitz 00:12, 6 October 2006 (UTC)

Isn't the setup mentioned in that section a bit weird, why should each of the two machines treat the other as the default gateway? Wouldn't that cause packets to other (non-existent) hosts to bounce back and forth between the machines until TTL runs out? At the most, one could have a default gateway, but even that is not necessary or useful if you have a proper routing table. 85.0.184.164 13:07, 11 March 2007 (UTC)

Yea, maybe it could be improved, but (as noted), this is not a text on networking. As I saw it, this was a very simplified overview on how to make two computers talk and that it was succinct, relevant, and germane as applied. At the very least, some newbie looking to tie two computers together and coming to this page to find out about crossover cables is put on notice that simply plugging in the cable is not enough. IMHO, a more fully developed explanation on how to do this, default gateways, possible modifications to the HOST/HOSTS file(s) and/or routing tables is way beyond the scope of this article. Jharris1993 04:13, 14 March 2007 (UTC)
Why is any of that needed? A default gateway (or anything beyond a basic routing table) is only for getting outside the local subnet. For the 2 machines to communicate with each other, they just send packets to the IP address of the other (with correct MAC addresses etc. and send the packets down the cable). The only OS i know of which is affected by lack of default gateways is Linux, but that's a problem with linux. — Lee Carré 16:04, 9 July 2007 (UTC)
That's a fair case (I think, but I don't have the expertise to verify it), and I'll suggest that you may either reword it or remove it (although I'm sure some readers might struggle what to use as a default gateway, since I think you need it for any TCP/IP network setup). +mt 16:57, 9 July 2007 (UTC)

[edit] Too many pictures

One amature picture of cable ends is enough. Users find it a lot more useful to have a detailed pinout for their reference.

[edit] Refresh / Update

I have made some edits that are (hopefully) viewed as an improvement on the original.

  1. I added references to both the T568-A and T568-B "standards" to the pinout tables.
  2. I copied (and modified) the original table, showing it as a four-pair crossover, since the newer network types need all four pairs crossed.
  3. I added explanatory comments about the T568-A/B wiring formats, since in my experience this has been a source of confusion. (They really are interchangeable, you just need to use the same format at each end.)
  4. I also inserted comments between the two pinout tables explaning that there may be situations where the "older" style may be preferable - and that some equipment can be fussy about which pairs are crossed, and which are not.
  5. I broke out the "Cable Pinouts" and "Other Technologies into separate sections to make things clearer.

Comments:

Thanks to whomever added the pictures and the original table. They really help liven up the page and make the information much more easily grasped.

Regarding the comment about "Wikipedia not being a 'user manual' but merely a 'source of information'..." Where do you/we draw the line? I came to Wikipedia, as a source of information, and in this case the "how-to" kind of information is often what the visitor wants.

In my own case, I came here looking for information about how to make the cable and found the tabular form for the pinout (now pinouts) most instructive.

Constructive criticism is welcomed. Flame-mail to /dev/null. ( :-) )

Jharris1993 04:13, 14 March 2007 (UTC)

Edited by Jharris1993 17:08, 15 March 2007 (UTC) to clarify and remove redundant content.

[edit] MDI

Can we please add a reference to MDI (medium dependent interface, if I'm correct), to explain this abbreviation, and to provide more information? —Preceding unsigned comment added by 82.171.28.115 (talk) 10:23, 17 February 2008 (UTC)

[edit] Okay, a little re-wording/explanation might help.

For the computer newbie's here, this article is like trying to read the Rosetta Stone while being illiterate of ANY language. The section entitled "Overview" is complete gibberish. Example: "The 10BASE-T and 100BASE-TX Ethernet standards use one wire pair for transmission in each direction. The Tx+ line from each device connects to the tip conductor and the Tx- line is connected to the ring. This requires that the transmit pair of each device be connected to the receive pair of the device on the other end. When a terminal device is connected to a switch or hub, this crossover is done internally in the switch or hub. A standard straight through cable is used for this purpose where each pin of the connector on one end is connected to the corresponding pin on the other connector."

What I got from that is this: "Stick one end in the ethernet plug on computer A and then stick the other end into Computer B's ethernet plug". However, I'm probably wrong. Why? Because I have no idea what a "10BASE-T and 100BASE-TX" is/are, or what a "Tx+" or "Tx-" are. Hell, looking at this, for all I know I need a special Ethernet Cable, not like the one I'm using to connect my PC into the wall in my room. Anyone care to make this article a little more reader-friendly? Please? Paladin Hammer (talk) 02:34, 20 March 2008 (UTC)

[edit] Gigabit Crossover

I've never heard of Gigabit crossover, and I've been networking for quite some time, now. Has anyone else heard of this? It seems unusual to try to push a different pinout for this.--68.146.138.239 (talk) 15:05, 30 March 2008 (UTC)