Log In

Come Join Us!

Are you a
Computer / IT professional?
Join Tek-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Tek-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Cabling FAQ

Cat 5 Cable Standards

Straight-through and crossover cables revisited by phuzzy42
Posted: 28 Dec 05

Getting the right color wire to the right pin in a connector can be confusing.  Hold the connector with its clip facing down and with the cable opening facing you.  The leftmost pin is pin #1, then pin #2, and so on.

Most CAT5 and CAT6 is wired using the EIA/TIA 568B standard.  Regardless of whether you use 568A or 568B,  straight-through cables connect the same pin numbers together on each end of the cable - pin #1 on one end goes to pin #1 on the other, pin #2 to pin #2, etc.  Crossover cables swap the positions of the orange and green pairs on one connector so the transmit on one end goes to the receive on the other and vice versa - one connector is wired using 568A and the other uses 568B.

The chart below shows which color wire goes to which connector pin on each end of a cable.


   EIA/TIA 568B           STRAIGHT-THROUGH           EIA/TIA 568B

1  Orange/White ------------------------------------ Orange/White  1

2  Orange ------------------------------------------------ Orange  2

3  Green/White -------------------------------------- Green/White  3

4  Blue ---------------------------------------------------- Blue  4

5  Blue/White ---------------------------------------- Blue/White  5

6  Green -------------------------------------------------- Green  6

7  Brown/White -------------------------------------- Brown/White  7

8  Brown -------------------------------------------------- Brown  8

   EIA/TIA 568B               CROSSOVER              EIA/TIA 568A

1  Orange/White ----------------+   +---------------- Green/White  1
                                 \ /
2  Orange ------------------+     \  +--------------------- Green  2
                             \   / \/
3  Green/White ---------------\-+  /+--------------- Orange/White  3
                               \  /
4  Blue ------------------------\/-------------------------- Blue  4
5  Blue/White -----------------/--\------------------- Blue/White  5
                              /    \
6  Green --------------------+      +--------------------- Orange  6

7  Brown/White -------------------------------------- Brown/White  7

8  Brown -------------------------------------------------- Brown  8

Keep these things in mind to make your cabling more reliable:

*  Keep the twists in the wires as close to the pins as possible to reduce noise and crosstalk.
*  Be careful how tight a turn around corners the cable takes - no sharp bends and no kinks.
*  Don't let people walk on the cable or put anything heavy on it. No pinching!
*  Keep cable at least 3' away from electrical wires if they run parallel to each other.
*  When bundling several cables together, it's better to use velcro instead of wire ties.

Back to Cabling FAQ Index
Back to Cabling Forum

My Archive

Close Box

Join Tek-Tips® Today!

Join your peers on the Internet's largest technical computer professional community.
It's easy to join and it's free.

Here's Why Members Love Tek-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close