How to tell a Ethernet cable is conventional or crossover

ethernet crossover-cable

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Solution 1

Look at the ends of the cable. If the color order is identical, then it is a patch cable (or as you said "conventional"). If the color orders are different, then it is a crossover. Also, keep in mind that USUALLY (not all the time) crossover cables are red. Obviously they can come in any color though.

Below you can see the colors of the twisted pair wires inside of the RJ-45 connector. For more information on this, or if you would like to know about the TIA/EIA-568-A or the TIA/EIA-568-B standards, please refer to this wiki page.

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Solution 2

Most modern Ethernet equipment will auto-negotiate and doesn't care whether the cable is cross-over or not.

Solution 3

Don't worry, most modern Ethernet cards support both modes and will automatically recognize type of the cable.

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baz

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Updated on September 17, 2022

Comments

baz almost 2 years

I want to use a crossover Ethernet cable to connect two computers directly for file transfer between the two. I have several Ethernet cables, but not sure if they are crossover? How to tell a Ethernet cable is conventional or crossover? Thanks and regards!
- user5249203 over 13 years
  
  I believe most UTP/RJ45 Ethernet interfaces nowadays are Auto-MDIX and therefore you may find that any Cat5/Cat6 Ethernet patch cable will work. Of course, this might apply only to switches and not to computer NICs - in which case all bets are off.
Dennis Williamson over 13 years

See Network Cable Color Conventions for a discussion of jacket color.
Zan Lynx over 13 years

This happens to be a requirement of Gigabit Ethernet. 100 Mbit will not do it though.
Dennis Williamson over 13 years

@Zan: Most modern 100BaseT equipment supports Auto-MDIX. It's specified, but optional, in GbE.
Zan Lynx over 13 years

I'll try to find a reference source, but I am almost certain auto-MDIX is a requirement of the Gigabit Ethernet specification. I've used a lot of 100 Mbit equipment that will not work without the correct cable so I don't know about "most modern 100BaseT."
Zan Lynx over 13 years

Okay. It is optional, although I've never run into a system that didn't have it. See standards.ieee.org/getieee802/download/802.3-2008_section3.p‌df section 40.4.4: "Implementation of an automatic MDI/MDI-X configuration is optional for 1000BASE-T devices." Sorry about that. My confusion.
David over 13 years

Is this the answer you were looking for @Tim? If so, you can accept it by clicking the arrow to the left of my answer.
David about 13 years

@Tim. Is this the answer you were looking for? If so, you can accept it by clicking the arrow to the left of my answer