What are the differences between straight cable and crossover cable?

[oyster163]

Hi all,
I am just wondering what the actual differences a between straight cable and a crossover cable are? Speed, connection, struture, etc. ?
Theoretically, a straight cable is used to connect a computer to a hub whereas a crossover cable is used to connect 2 computers directly. But what I have noticed so far is that a crossover cable can be used to connect the computer to the hub too. I'm not sure abt whether straight cable can be connected 2 computers directly?
Are there any ways to recognise 2 different kinds of cables physically (without connecting to the computer)?
If anyone knows abt it, pls feel free to share with others.

Thanks,
Oyster

[jkrohn]

Look at the pinout of the cables. Here you can see them diagramed.
http://www.winnpsb.org/Tutorials/RJ45/default.htm

And a straight cable will not work to connect two computer together.

Jkrohn

[BeatYouWithShoe]

http://www.makeitsimple.com/how-to/dyi_crossover.htm

like jkrohn said, crossover used to connect to PCs directly together, also used for connecting networking devices together like Switch to Switch etc.

[oyster163]

Thanks a lot for this info, jkrohn and BeatYouWithShoe. It explains to me a lot about problems I met. Thanks again

[John Prophet]

there is no difference as far as speed etc

the crossover crosses the send and rx wire...otherwise if there are 2 nics they will both be trying to send on the same send wire etc...that is a real non technical way to look at it.

the way I think of it is that straight cables connect two DIFFERENT types of devices..whereas crossover cables connect two of the SAME type

so a nic to a nic needs a crossover cuz they are the same

a nic to a hub uses a straight

a hub to a hub uses a crossover


now..to make it more confusing they often have ports on hubs and routers called "uplink" ports....these uplink ports do the job of the crossover cable...so if you come from the uplink port of a switch to another switch you dont need a crossover cuz the uplink did the "crossing" for you

now if you come from an uplink port you are supposed to just go to a regular port on the next hub...if you go from uplink port to uplink port you have "crossed" it twice so in effect it is now 'uncrossed' again so you STILL need a crossover cable, lol

and to FURTHER complicate it...now they have a feature on lots of switches and hubs etc called "auto-mdix" or "auto mdi/mdix"....that is the new thing where it doesnt matter what kind of cable you use, lol..cuz it will just auto detect the proper connection type no matter which cable you use.

JP

[billi9709]

there is no difference as far as speed etc

the crossover crosses the send and rx wire...otherwise if there are 2 nics they will both be trying to send on the same send wire etc...that is a real non technical way to look at it.

the way I think of it is that straight cables connect two DIFFERENT types of devices..whereas crossover cables connect two of the SAME type

so a nic to a nic needs a crossover cuz they are the same

a nic to a hub uses a straight

a hub to a hub uses a crossover


now..to make it more confusing they often have ports on hubs and routers called "uplink" ports....these uplink ports do the job of the crossover cable...so if you come from the uplink port of a switch to another switch you dont need a crossover cuz the uplink did the "crossing" for you

now if you come from an uplink port you are supposed to just go to a regular port on the next hub...if you go from uplink port to uplink port you have "crossed" it twice so in effect it is now 'uncrossed' again so you STILL need a crossover cable, lol

and to FURTHER complicate it...now they have a feature on lots of switches and hubs etc called "auto-mdix" or "auto mdi/mdix"....that is the new thing where it doesnt matter what kind of cable you use, lol..cuz it will just auto detect the proper connection type no matter which cable you use.

JP

[azher91]

Simple
Straight - Used for everyday daily use, connecting from your hub to your computer
Cross-over - Used for connecting two PC's/Laptop or Switch to Switch - basicially you can create a mini local network and share file's, Ive had it setup at my home. basically a small file server.