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January 27th, 2008 • Related • Filed Under

There are generally three main types of networking cables: straight-through, crossover, and rollover cables. Each cable type has a distinct use, and should not be used in place of another. So how do you know which cable to use for what you need?

The Purpose of Straight-Through Cables

Straight-through cables get their name from how they are made. Out of the 8 pins that exist on both ends of an Ethernet cable, each pin connects to the same pin on the opposite side. Review the diagram below for a visual example:

http://learn -networking.com/network -design/the -difference -between -straight -through -cross ... 2/24/2011 The Difference Between Straight Through, Crossover, And Rollover Cables : Learn -Netw ... Page 2 of 10

Notice how each wire corresponds to the same pin. This kind of wiring diagram is part of the 568A standard. The 568B standard achieves the same thing, but through different wiring. It is generally accepted to use the 568A standard as pictured, since it allows compatibility with certain telephone hardware- while 568B doesn’t.

Straight-through cables are primarily used for connecting unlike devices. A straight-through cable is typically used in the following situations:

Use a straight-through cable when:

• 1. Connecting a router to a hub

• 2. Connecting a computer to a swtich

• 3. Connecting a LAN port to a switch, hub, or computer

Note that some devices such as routers will have advanced circuitry, which enables them to use both crossover and straight-through cables. In general, however, straight-through cables will not connect a computer and router because they are not “unlike devices.”

The Purpose of Crossover Cables

Crossover cables are very similar to straight-through cables, except that they have pairs of wires that crisscross. This allows for two devices to communicate at the same time. Unlike straight-through cables, we use crossover cables to connect like devices. A visual example can be seen below:

Notice how all we did was switch the orange-white and green-white wires, and then the orange and green wires. This will enable like devices to communicate. Crossover cables are typically used in the following situations:

Use a crossover cable when:

• 1. Connecting a computer to a router

• 2. Connecting a computer to a computer

• 3. Connecting a router to a router

• 4. Connecting a switch to a switch

• 5. Connecting a hub to a hub

While the rule of thumb is to use crossover cables with like devices, some devices do not follow standards. Others provide support for both types of cables. However, there is still something that both crossover and straight-through cables can’t do.

The Purpose of Rollover Cables

Rollover cables, like other cabling types, got their name from how they are wired. Rollover cables essentially have one end of the cable wired exactly opposite from the other. This essentially “rolls over” the wires- but why would we need to do such a thing? Rollover cables, also called Yost cables, usually connect a device to a router or switch’s console port. This allows a programmer to make a connection to the router or switch, and program it as needed. A visual example can be seen below:

Notice that each wire is simply “rolled over.” These types of cables are generally not used very much, so are usually colored differently from other types of cables.

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There Are 22 Responses So Far. »

1. Pingback by CCNA 1 Module 3 Exam Solutions : Learn-Networking.com on 28 January 2008 :

[...] More Info: The Difference Between Straight Through, Crossover, And Rollover Cables [...]

2. Pingback by CCNA 1 Module 5 Exam Solutions : Learn-Networking.com on 28 January 2008 :

[...] More Info: The Difference Between Straight Through, Crossover, And Rollover Cables [...]

Comment by kiran on 28 July 2008 :

thank to u. i am searching for theis. i got it after long time

Comment by jdac on 18 December 2008 :

A definition of what “like” and “unlike” devices would be helpful. Is it a matter of what OSI stack level they operate on, or something else?

Comment by eyzA on 24 January 2009 :

Good information. I really need all this for my assignment, which I supposed to submit tomorrow! Thanks.

Comment by Usman on 2 February 2009 :

Thanks bro its great stuff

Comment by okoro_kono on 4 February 2009 :

Beautiful solution to a nagging question. Will be an assignment to my ccna class

Comment by Raja Ayaz Khaliqdad on 23 April 2009 :

The main point in these definitions is this computer and router are not unlike devices so you can use crossover as well as straight cable to connect them is brilliant it help me a lot.

Comment by Denrele on 22 June 2009 :

this is very nice…my boss would have made me look like a fool

10.

Comment by joe on 20 July 2009 :

thank you so much! loveet!

11.

Comment by MARTINS TUNDE on 29 July 2009 :

i can now say i am convinced with the differentiation.

12.

Comment by mohammed sayeed on 24 August 2009 :

hi how to connect a 24 port d link switch to 15 computer and one server and router modem dsl

then how to pair cables

13.

Comment by imaobong ezekiel on 2 October 2009 :

this is one of the best materials i’ve seen on cabling.i recommend it for beginners in networking.

14.

Comment by anonymous on 20 October 2009 :

Very nice, just read it a day before interviews and it helped big time!!!

15.

Comment by Ali on 6 November 2009 :

Note: If there is auto MDI/MDI-X feature support on the switch, hub, network card or other network devices, you don’t have to use crossover cable in the situation which I mentioned above. This is because crossover function would be enabled automatically when it’s needed.

16.

Comment by juruga on 16 December 2009 :

Hi, Its nice I read through the differences of the three and where to use each but please there is still need to have more clear illustrations of the cables. thanks

17.

Comment by Lawrence on 18 January 2010 :

Thank you very much for this wonderful piece of art!

18.

Comment by Brea on 22 June 2010 :

hello. this is brea uhmm can i ask whats the definition of STRAIGHT ETHERNET CABLE? is this the meaning? >Connecting a computer to a swtich . thanks ^^

19. Comment by Macki on 14 September 2010 :

Hey. It’s kinda confusing. From the CCNA’s diagram, it shows two T658B for straight through, while yours are two T658A.

20.

Comment by shan on 12 October 2010 :

Simple approach to explain the type of cabling. good work, thanks!

21.

Comment by Rabiya on 15 October 2010 :

Good stuff for my assigment

22.

Comment by Faisal on 15 February 2011 :

T568A and T568B is the standard of assignment of eight colored twisted pair cable. Both have different sequence of eight colored wires.

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