Talk:Ethernet crossover cable

10GBase-T
Does anyone know about 10GBase-T? I can't find any references about making a cross-over cable for 10GBase-T or discussions about whether this work. If anyone can assist I think this is important to complete this article. —Preceding unsigned comment added by Paulsheer (talk • contribs) 12:26, 2 March 2010 (UTC)
 * No special cross-over cable is required for 1GBase-T or 10GBase-T. — Preceding unsigned comment added by 173.71.30.196 (talk) 01:02, 4 November 2013 (UTC)
 * I recall from my networking days that 10GBase-T was required to automatically do crossover where needed. So yes, it should definitely be added to this article. (The article already correctly notes that most but not all 1000Base-T implementations automatically do crossover where needed.) Greg (talk) 21:59, 23 October 2016 (UTC)


 * I've added the faster standards to the article. Note that from 1000BASE-T onwards, the pair matching in the PMA sublayer makes a crossover completely unnecessary. For these interfaces, the crossover function is still optional to 100BASE-TX and 10BASE-T modes but since there are both transmitters and receivers present on each pair anyway, there's just very few logic required. --Zac67 (talk) 06:35, 24 October 2016 (UTC)

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)

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)


 * While I have never seen a Gigabit crossover either, it makes sense why it would have a different pinout from the non-gigabit crossover. The non-gigabit cables use only four of the eight wires for transmitting data (one in each direction X 2 for full duplex) and those four wires are the ones that are crossed over. Since Gigabit uses all the wires inside the cable, then all wires must be crossed over. Jk20077 (talk) 20:34, 23 December 2008 (UTC)

Isn't this just complete crap, in gigabit crossover cable: "..and also requires the solid/striped within each of those two pairs to be swapped." No way! Is this a joke? Do not switch the polarity! Hyvatti (talk) 12:17, 17 April 2009 (UTC)


 * The polarity switching recommendation in the 1000BASE-T crossover pinouts was uncited and very suspect. Wrong information is much worse than no information. I have deleted it. Please provide a specific citation to a cabling standard if you want to bring it back --Kvng (talk) 13:24, 30 May 2009 (UTC)


 * Then you should also delete the top right Image (Vergleich 2von2 Crossoverkabel.gif) noted as Crossover cable suitable for use with 100BASE-T4, because it has the same pinout! [Will look into a specific citation to a cabling standard] 15:50, 31 May 2009 (UTC)  —Preceding unsigned comment added by 85.75.90.94 (talk)


 * You can always Google it before deleting! I think this "IEEE Standards Association" link proves me right, but it is not the best citation, since it references to the pinout but for other purposes...
 * http://grouper.ieee.org/groups/1394/c/200303/S800BT-03042003.pdf
 * More google results...
 * http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/css11500series/v8.20_v8.10/installation/guide/Pinouts.pdf
 * http://support.apple.com/kb/TA26096?viewlocale=en_US
 * http://www.allpinouts.org/index.php/Ethernet_1000Base-T_Gigabit
 * http://pinouts.ru/Net/ethernet1000baset_pinout.shtml
 * http://www.cabling-design.com/references/pinouts/1000base-t-crossover.shtml —Preceding unsigned comment added by 85.75.90.94 (talk) 15:43, 31 May 2009 (UTC)


 * I've edited the photo caption as per your suggestion. How about if we go directly to the source? IEEE 802 standards may be downloaded at no charge from http://standards.ieee.org/getieee802/802.3.html.
 * The 10/100BASE-T crossover is described in clause 14.5.2 (section one) of IEEE 802.3-2005. The 1000BASE-T crossover is described in clause 40.8.2 (section three). By my reading of this, the 1000BASE-T crossover description that I deleted was, as Hyvatti pointed out, incorrect. Feel free to restore a corrected version. I'll be happy to proof it. --Kvng (talk) 18:14, 31 May 2009 (UTC)


 * But there was NO polarity switching recommendation at all from the first place! The section you deleted was exactly consistent with the information provided in the page you mentioned above (40.8.2 page 226). You can find there the "Table 40–12—Assignment of PMA signal to MDI and MDI-X pin-outs" where the Contact MDI MDI-X are exactly as I had mentioned! I cannot understand where is the problem with that?!? Please explain... —Preceding unsigned comment added by 85.75.98.249 (talk) 20:06, 31 May 2009 (UTC)


 * Please take another look at the material in question http://en.wikipedia.org/w/index.php?title=Ethernet_crossover_cable&oldid=293301394. The polarity on pairs 1 and 4 are reversed. I'm not comfortable reverting the deletions. Feel free to take a crack at it yourself. I'll come back proof it. --Kvng (talk) 21:51, 31 May 2009 (UTC)


 * The polarity is NOT reversed. In 1000BASE-T, positive (+) wires ARE NOT THE STRIPED ONES, but "white/green stripe", "white/orange stripe", "blue solid" and "white/brown stripe" as you can see in the IEEE standards (Pins 1,3,4 and 7). The negative (-) ones are "green solid", "white/blue stripe", "orange solid" and "brown solid" (Pins 2,5,6 and 8). So, by connecting "blue solid" pin 4 (BI_DC+) to "white/brown stripe" pin 7 (BI_DD+) you DO NOT REVERSE polarity. I guess all of you thought that striped colors are always positive, so that is why you could not see the obvious. SO, do you agree on reverting the deletions? —Preceding unsigned comment added by 85.75.98.249 (talk) 22:17, 31 May 2009 (UTC)


 * Yes, assuming that there was a constant mapping of +/- to striped/sold is how I was led astray on this. These wiring "standards" have been around since the invention of the telephone so it is no wonder things are a bit strange. I see your point now. On careful inspection, I am not able to find any error in the original article. I agree the deletions should be reverted and have done so. Thanks for your patience --Kvng (talk) 16:29, 1 June 2009 (UTC)


 * The moral of this story is - ALWAYS verify the details, don't assume the designers followed any standards (even if it would be insane not to). The gigabit crossover cable image still has an incorrect comment attached, saying that the pinout is incorrect. Should this be removed? — Preceding unsigned comment added by Jjakob (talk • contribs) 16:19, 30 March 2013 (UTC)

I've removed the 1000BASE-T crossover sections and clarified with a source why this is not required. I understand gigabit crossover may defined in some places, but its use always seem to cause more harm than good. Catphish (talk) 09:41, 1 June 2015 (UTC)

So on this page it has an item about crossover cables and one about MDI-X for 1000BASE-T "there are no dedicated transmit and receive pairs, and consequently, crossover cables are never required for 1000BASE-T communication" Then we have "Although Auto MDI-X was specified as an optional feature in the 1000BASE-T standard,[5] in practice it is implemented widely on most interfaces." ie This seems to say cross over is never required but that you can have Auto MDI-X. Whilst not contradictory it does seem to imply that to implement MDI-X is possible but when implemented then its not needed anyway as straight through or cross over cables will work any way ? 05:01, 29 October 2015 (UTC) I think the relation between these two statements should be clarified Ross (talk) 08:41, 29 October 2015 (UTC)


 * Valid point, there is much confusion. The "Auto MDI-X" function is only ever required for 10 or 100 Mbit links. GbE and 10GE have the PMA sublayer sort out the pairs. I've tried to change the description more in this way. --Zac67 (talk) 22:22, 29 October 2015 (UTC)


 * Thank you for your changes. I think your description even better clarifies what I was trying to explain with my original edit. I have also removed the terms "Gigabit" and "T568B" from the image description at the top of the page as 1) This configuration isn't specific to Gigabit (or even ideal for Gigabit) and 2) Both ends are not T568B I don't believe. Catphish (talk) 13:06, 1 November 2015 (UTC)


 * Good job. Note that a crossover cable is T568A on one side and T568B on the other. Both sides by the same variant is a straight cable. In the photo, the left connector is -B, the right one -A, check TIA/EIA-568. --Zac67 (talk) 15:00, 1 November 2015 (UTC)


 * You seem to forget that 1000BASE-T still uses the 10Mbit link pulses for auto-negotiation. If both PHY's transmit their link pulses on only one pair, and listen only on the other pair, auto-negotiation will never even start so you won't be able to get a link. If you inspect the datasheet of some random PHY's, you will see that it is still possible to disable auto-MDI-X (actually it is disabled by default), and it just can't connect if you use two endpoints if you don't use a cross-cable. 80.157.5.35 (talk) 06:24, 11 August 2016 (UTC)


 * 10BASE-T link pulses have been obsoleted by Auto-Negotiation, the newer link codes build on top of that. Of course the sent pulses must be received on the other end in both directions, so when you deactivate Auto MDI-X the pulses are expected on a specific pair. Your point being? I guess just about any network device you can buy today has Auto MDI-X by default, even if the PHYs themselves don't; our switches show pretty much random MDI and MDI-X mode ports for FE. --Zac67 (talk) 17:41, 11 August 2016 (UTC)

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)

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  &#9998; 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)

I have read here in this Talk page that the cable is a valid 1000-BaseT crossover cable... But I have found this hard to verify anywhere on the internet, much less through any cited sources on Wikipedia. There are some low-quality sources out there (low authority) that back up this photo, so I'm starting to believe it's "legit". Still, a better source is needed.

We should add a high-quality source to the article explaining why this mythical "brown in the middle" wiring is actually correct -- only for gigabit -- or else we should get a picture of a typical T568A - T568B crossover cable to replace this confusing picture. Anything else is troublesome and misleading.

My two cents.

2601:4B:300:5D46:456B:114F:C8D5:F188 (talk) 16:05, 10 December 2017 (UTC)


 * A 1000BASE-T crossover cable is described in IEEE 802.3 Clause 40.8. The crossed pairs in the photo match this description: 1-2 with 3-6 and 4-5 with 7-8. However, the very same clause states that the crossover is only required for autonegotiation to work which has been obsoleted by Auto MDI-X. --Zac67 (talk) 17:34, 10 December 2017 (UTC)


 * Great. I trust that that is true. Can we get that as a cited source in the article? I propose it should be right after the text in the picture's caption. We still need an inline citation per Verifiability.


 * -- 2601:4B:300:5D46:AD64:FA1B:CF75:5F10 (talk) 04:42, 14 December 2017 (UTC)


 * I'm not sure the caption is the right place for this. We do already have a reference to IEEE 802.3 Clause 40.8 in . Adding another instance of this in the wiring chart may be warranted. ~Kvng (talk) 15:40, 16 December 2017 (UTC)

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. &mdash;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).


 * Quite true, there is something like a Rollover cable! Wiki link here in my Comment. That Wikipedia article however,  really ought to have a diagram, drawing, photograph,  showing the eight (8) wires (4 pairs total) "rolling-over," i.e. how it is different from a Straight through vs a Crossover Cable. Good question! From Peter a.k.a. Vid2vid (talk) 23:29, 9 January 2020 (UTC).

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). + m t  16:57, 9 July 2007 (UTC)

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. --[Unsigned topic, unknown author]


 * I reworked the pictures a bit and added a wiring diagram. Not sure if this is better but web are all "amateur" here. W Nowicki (talk) 00:09, 19 June 2011 (UTC)


 * I'd say it's an improvement. The previous gallery section was a confusing mess. + m t  00:30, 19 June 2011 (UTC)


 * - - I say in the Networking world, the more pictures the better, but they could be smaller, lower-resolution, simply drawings rather than photographs (bandwidth and page loading speed concerns ✅ on). From Peter, a.k.a. Vid2vid (talk) 23:18, 9 January 2020 (UTC).

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.

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)

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)

"Networks created..." redux
[I am bringing this up here because I took the time to find out that it has been in the article over two years (minus this) and I see it was discussed above]

Can we please get rid of this section? My problem isn't that it is possibly manual-ish, but that it is not related to crossover cables. The two computers might not be using Internet Protocol, and if they are, networks not connected (or even just not visible) to the Internet/outside world can use any addresses they want, since there couldn't be any address conflicts or things. As someone who has been through the Cisco Networking Academy, I should know what I'm talking about. Thanks. Jason McHuff (talk) 08:06, 21 September 2008 (UTC)


 * Your point regarding the complexities in setting up a network is taken. This article should really be about the cable configuration and related hardware. I've moved the section to the best available Wikibook (there may be a better one). I put a reference to it in the "See also" here, since it is useful for anyone who hasn't been through the Cisco Networking Academy and needs to set-up a simple two-computer network. + m t  08:34, 22 September 2008 (UTC)


 * Thank you. And I do understand that many, if not most, people in the would don't know about networking or the details of directly connecting two computers.  I've actually had problems myself, but they've been hardware issues.  Jason McHuff (talk) 04:55, 23 September 2008 (UTC)

This seems to have been the "how to" info, so can that complaint be removed now? Actually I had never heard the expression "crossover Ethernet network" but its seems to be used in a few cases; I usually heard it called something like a "back to back" connection. And of course not to be confused with an audio crossover network which is the much more common term. I propose we add one sentence that has the "what" instead of "how to" instead of censoring it totally (although link is there). e.g. "A simple networking using this kind of cable was sometimes called a "crossover Ethernet network" which required some manual configuration." W Nowicki (talk) 19:31, 17 June 2011 (UTC)
 * It was actually added here but that tag should still be removed. I removed the same tag by the same editor on other articles already. He tagged all the articles which had pinouts or colour codes in tables, including non-Ethernet articles such as Modular connector and I think Registered jack. --Tothwolf (talk) 20:12, 17 June 2011 (UTC)

Tip and Ring
"The Tx+ line from each device connects to the tip conductor, and the Tx- line is connected to the ring."

These terms are, to me, totally inappropriate when discussing modular connectors - I assume they come from TRS jack technology but I've never seen ethernet over TRS connectors.

If someone doesn't educate me shortly, I'll rewrite this paragraph.

62.49.27.35 (talk) 13:22, 27 April 2009 (UTC)

POE concerns
''I removed this section from the Crossover cable article. If it belongs anywhere, it belongs in this article. I suggest it needs some attention first, however --Kvng (talk) 12:36, 30 May 2009 (UTC)''

POE however may not necessarily work when the normal 10/100 wires that are used for POE are used with crossover specification T568B for 1000T.

It seems that the T568B specification is being used to refer to 1000T crossover also. Which does not seem fair or make sense to reuse a standard and then change it to suit another need. There is one T568B specification for 10/100 and another for 1000T. This is because 10/100 uses only two pair for data and has two unused pair that are now also being used for POE. 1000T uses all four pair (8 wires) for data and has different requirements for crossover because it requires four pairs (8 wires) to be crossed. According to the original T568B specification the location of the blue wires were not supposed to change.

There needs to be another specification for 1000T crossover. It would make sense if there were three specifications to keep the first specifications intact. Example T568A,T568B,T568GB. This could eliminate problems when you expect T568B 10/100 version and actually get the 1000T version T568GB instead.

According to the 802.11af specification: The polarity of the DC supply may be inverted by cross cables; the powered device must operate with either pair: spare pairs 4-5 and 7-8 or data pairs 1-2 and 3-6. Polarity is required on data pairs, and ambiguously implemented for spare pairs, with the use of a bridge rectifier. However some POE devices were developed before an IEEE standard was born. Cisco's original PoE equipment was manufactured many years before there was an IEEE standard for delivering PoE. A simple method of homebrew PoE involves wiring the spare pairs 4-5 (positive) and 7-8 (negative) to an appropriate DC power source.

Update
In partial response to some of the above comments: isn't this topic of historical interest now? It has been 12 years since Auto MDI/X has been introduced. Does anyone still make equipment that needs crossover cables? In particular the mention of 1000BASE-T needing special cables is quite odd, since all 1000BASE-T PHYs that I know of have auto sense so wil work with either sex cable. Is there low-end stuff that still does not implement auto sense? I do see the cables still available, but as long as one end has a modern PHY then this should all be in past tense. W Nowicki (talk) 19:31, 17 June 2011 (UTC)


 * I've evaluated a lot of gigabit Ethernet equipment over the past two years and have not come across any 1000BASE-T port that does not support auto MDI/X. On the other hand the 802.3 standard specifically does not require it so someone could build one if they were so inclined. --Kvng (talk) 01:55, 21 June 2011 (UTC)

Alas, it looks like some anonymous editors are putting more present tense back in? Along with more blank lines and redundancies. Hope to work on it. W Nowicki (talk) 18:47, 12 August 2011 (UTC) Also just realized that we need to clarify this generally applies to twisted-pair electrical wires. Most optical PHYs also use crossover cables but all the time instead of rarely. The auto sense is not done since optical splitters/switches are not so cheap, except on the single fiber PHY I think. A source would be nice though. W Nowicki (talk) 20:10, 12 August 2011 (UTC)

Two new images
I received two new images on OTRS today, but I'm not sure if they are so good to be published on the article... Hopefully someone here can make that decision for me: and. Edoderoo (talk) 14:27, 28 June 2011 (UTC)


 * Hmm, the first one is a screenshot of my diagram File:Ethernet MDI crossover.svg with a caption in some other language (Dutch?). The second is a color coded version of the same thing, plus a connector pair drawn in. I was going to add color to mine, but wanted to show the pair-twisting and make the "cross over" explicit. The first should probably be deleted; will comment on commons. The seond picture looks a bit busy to me, but would welcome other points of view, since I am an engineer not an artist. W Nowicki (talk) 15:43, 28 June 2011 (UTC)


 * Hard to offer any additional input; the pictures have disappeared. --Kvng (talk) 15:24, 4 July 2011 (UTC)


 * Oops, sorry, should have followed up. When I pointed out the obvious resemblance (a bug in mine for example showed up in the first one) the OTRS uploader immediately deleted them. I did not think they caused any harm and would have prefered to keep them around while discussion ensued, but probably OTRS needs to err on the side of being careful. I did add a touch of color to mine, although it is a bit tough since the color is actually on the wires and not the pins. But this is not a "how to" anyway just trying to give an overview of the concept. Probably more drab articles could use diagrams too, but they are tedious to make. W Nowicki (talk) 19:01, 4 July 2011 (UTC)

Incorrect information on 1000TX
The edit on 07:35, 1 August 2011 88.222.25.105 seems to have introduced incorrect information about T568B cables. I lack the time and/or experience to roll the following 10+ updates into a revert; can anyone help out? 204.57.81.7 (talk) 18:46, 19 August 2011 (UTC)


 * Generally, unexplained (no edit comments) changes done by anonymous users are more dubious. Indeed, it looks like they swapped the polarity (+/-) of the wires within the pair as well as crossed the pairs. I do not have the specific standard documents handy, but seriously doubt that is what was done. I reverted both the edits; one swapped the polarity ont he "B" gigabit crossover, and the other on the "A". Would like to have someone else verify please to make sure which is correct. This of course really needs a source we can verify against! W Nowicki (talk) 18:28, 20 August 2011 (UTC)

Incorrect information on 1000TX ???
I tested in article purpose cable (Gigabit T568A ctossover (1000BASE-T))

Testing on: Hardware 1 PC1 with Realtec PCI GBE Family controler PC2 with Intel 82566DM Gigabit controller (onboard)

Hardware 2 Four diverts IBM xSeries servers

The connector on the right shows: GreenWhite - Green - OrangeWhite - Blue - BlueWhite - Orange - BrownWhite - Brown The connector on the left shows: OrangeWhite - Orange - GreenWhite - BrownWhite - Brown - Green - Blue - BlueWhite

Hardware 1 and Hardware 2 was detected 100Mbps nework and work at that speed.

When cable was modified: The connector on the right shows: GreenWhite - Green - OrangeWhite - Blue - BlueWhite - Orange - BrownWhite - Brown The connector on the left shows: OrangeWhite - Orange - GreenWhite - Brown - BrownWhite - Green - BlueWhite - Blue

Hardware 1 and Hardware 2 was detected 1000Mbps nework and work at that speed.

Where is error?

Sory for my English — Preceding unsigned comment added by 88.222.25.105 (talk) 05:04, 27 August 2011 (UTC)


 * Not sure what you are asking. It looks like you are swapping the polarity of the pairs on pins 4-5 and pins 7-8. If it works for you, fine, I could certainly believe that some polarity swaps might work (depends on other details). But that would be what we call "original research", and we are supposed to base Wikipedia on verifiable sources. I checked a few sources and they agree polarity should not be crossed. My guess is in your first experiment one of the pins was not making contact or something else was going on. If indeed you are claiming that wiring according to the sources did not work. Unless the equipment you have is very old, it probably does Auto-MDIX anyway, so you could have used a simple straight cable probably. W Nowicki (talk) 20:05, 27 August 2011 (UTC)

Confusion between "Patch" and "Crossover"
Searching the internet, most sites agree that there are two kinds of CAT5 cables used for Ethernet networking: 1) "Patch" AKA "Straight-Through" 2) "Crossover"

However, several sites, especially stores selling cables, say that there are two kinds of "Patch cables": 1) "Straight-Through" (a type of Patch cable) 2) "Crossover" (a type of Patch cable) Click here for many examples

I think this Wiki page about Crossover cables and the other Wiki page about Patch cables need a section called "Terminology Confusion" which explains very clearly what the terms mean, to once and for all, clear up the confusion. — Preceding unsigned comment added by 24.73.83.122 (talk) 20:36, 15 August 2014 (UTC)


 * There's only one kind of Cat-5 cable and that's a Cat-5 cable – arbitrary length, no connectors. A patch cable is a confectioned cable of a certain length, a 8P8C connector on each end, in either straight-through or crossover pinout. Zac67 (talk) 22:33, 15 August 2014 (UTC)


 * There is special CAT5 patch cable that has stranded conductors. This opposed to CAT5 cable with solid conductors used for longer ("horizontal") runs. ~KvnG 13:56, 22 August 2014 (UTC)


 * I have changed the lead to remove "patch". "Patch" is not a synonym for "straight through". There are both straight through and crossover patch cables. If anyone thinks this needs further clarification, I suggest that be done at Patch cable. ~KvnG 13:56, 22 August 2014 (UTC)

No Early Mention of RJ45 / 8P8C? Suggestion, but might be incorrect or limited in scope
Howdy. I was going to add to the opening paragraph as follows, "Intentionally crossed wiring in the crossover cable connects the transmit signals at one end to the receive signals at the other end  (e.g. at the 8P8C a.k.a. RJ45 connector, where the 4 pairs or 8 wires total terminate) ." However, [1] Am I remiss in thinking that "Ethernet" always implies use of the RJ45 kind of connector? The Article is about what a crossover cable does, but by logic, isn't it true that *all* Crossover Cables use the T568A and T568B standards and use 4 wire pairs? Also, [2] Shouldn't SOMEWHERE in this article, perhaps in an InfoBox, shouldn't RJ45 be mentioned?? .. From Peter a.k.a. Vid2vid (talk) 23:40, 9 January 2020 (UTC).

Ethernet, 'crossover cable' article, why none for (Straight Thru) Ethernet cable?
[1] There is an article for Ethernet, another for 'Ethernet crossover cable,' ..why none for Ethernet cable? Or an article for Ethernet straight-through cable? Perhaps my searching abilities are sub-par in this (I.T.) Dept. ;-) Oh. P.s. [2] The pinout sections in this Article for half-crossed vs. fully-crossed are terrible and confusing, with unclear photos and diagrams; the paragraphs really should have very generic, straightforward, basic, layman's-terms text included saying something like PinX-to-PinY pinout is as follows: 1-to-3 and 2-to-6, then 3-to-1 and 6-to-2. My two cents. ...EDIT: From Peter a.k.a. Vid2vid (talk) 00:28, 10 January 2020 (UTC) (Was: Vid2vid (talk) 00:17, 10 January 2020 (UTC).).


 * Technically, an "Ethernet cable" doesn't even exist. Ethernet uses standard and multi-purpose twisted-pair cables. A crossover cable is different because it's only used for Ethernet (in that form). --Zac67 (talk) 07:20, 10 January 2020 (UTC)


 * We also have Networking cables. ~Kvng (talk) 14:45, 13 January 2020 (UTC)


 * Yes 1. but a WP article ought to exist solely on, Straight Through Ethernet Cable. Generically it's also known as a regular or non-crossover cable. And 2.  thanks for Networking cables article reminder but it's way too broad. From Peter a.k.a. Vid2vid (talk) 20:07, 13 January 2020 (UTC)


 * No, I don't think so. A straight-through Ethernet cable is only relevant in contrast to a crossover Ethernet cable (which is actually a thing because it's only used for Ethernet, unlike a straight TP cable). Ethernet cable is a subset of the already present Networking cables, patch cable, twisted-pair cable, and fiber-optic cable. It's also a superset of Category 5 cable, Category 6 cable, and so on. Theses are specific types of cables, unlike Ethernet cable which is very generic. Why do you think we really need a new article for something that's already better defined elsewhere? --Zac67 (talk) 21:01, 13 January 2020 (UTC)