How to make a loopback adapter without crimping tools.

October 19th, 2012 by Andrea Matesi 3572 Views

Suppose you were going for a 26+ hours flight, and suppose you had limited luggage allowance...what would you do with your fantastic (but nonetheless heavy...) crimping tool? But who cares!

You just need a physical loopback adapter :D

Here I'll show you how to make one without using a crimping tool:

  1. Buy a short standard cat.5e ethernet patch cable.
  2. Cut one of its ends (scissors, knife or strip it badly by rubbing it on the edge of a walkway).
  3. Once you have your short piece of cable, you need to remove the plastic from the pairs protecting the copper: this can be done with your teeth (!).
  4. Connect the pairs between them, such as to close the circuit, basically, as you'd do while connecting the pairs of a crossover cable to the other end.

Here's the right scheme:

OrangeWhite joined to GreenWhite.


Orange joined to Green.


Blue joined to BrownWhite.


BlueWhite joined to Brown.


Andrea's Physical Loopback Adapter

Once your pairs are joined, isolate them one-another (i.e.: with some scotch or duct tape).

Well done! Now you have a new physical gigabit loopback adapter like the one shown in the picture!

Posted in Tips and Tricks. | 1 Comment »