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how to make loopback ethernet jack

Posted on 2009-06-27
Medium Priority
Last Modified: 2012-06-27
i need an ethernet loopback jack. I know I need two wires. DOes one wire connect pins 1 and 3 and one wire connects pins 2 and 6? I can't remember?

Question by:WERAracer
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Assisted Solution

Emax_Solutions earned 80 total points
ID: 24728242
What I do is crimp a an ethernet cable into an RJ45 connector using the following configuration, clip facing down, right to left:

brown | brown wh | green | blue wh | blue | green wh | orange | orange wh

The I trim the cable to required size and strip sheath of coloured wires, exposing the metal. Then, twist together the

1. green white and orange white.
2. green and orange
3. blue and brown white
4. brown and blue white.

Tape of the exposed metal and make sure theres no short.

Thats it.
LVL 25

Assisted Solution

by:Ken Boone
Ken Boone earned 400 total points
ID: 24728506
FYI.. If you are doing this to put on a cisco router to keep the interface up for testing or lab purposes, you can get away without the ethernet loopback and enter this command on the ethernet interface:

no keepalive

That will force the ethernet interface to up/up without anything plugged in.
LVL 76

Accepted Solution

Alan Hardisty earned 1520 total points
ID: 24728514
This explains it and you just need two wires 1 and 3, then 2 and 6. 
LVL 76

Assisted Solution

by:Alan Hardisty
Alan Hardisty earned 1520 total points
ID: 24728549
As you suggested in your question - you are spot on!

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