How to Make Ethernet Loopback Cable
An Ethernet loopback cable is a portion of Ethernet cable where wires loop back around to the same plug that they originated from. This can be very useful when testing computer networking equipment, because it does not require a network to actually be in place for the tests to occur. Because the cable loops back on itself, information that is sent through the cable will return as though it was being sent from another computer. Creating an Ethernet loopback cable is relatively easy, requiring only a few minutes and basic Ethernet cable tools.
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Things You'll Need
- Knife or wire cutter
- Wire stripper
- RJ45 Ethernet connector
- RJ45 Ethernet crimping tool
- Ruler or tape measure
- Electrical tape (optional)
Instructions
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1
Measure a 6-inch portion of an Ethernet cable and cut both ends of it off. Carefully slice the cable's insulation down the length of the portion you have created, exposing the wires inside.
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2
Remove a single braided pair of wires from the insulation. Unbraid the wires to a length of approximately 2 inches on each end, then use your wire stripper to strip half an inch of the insulation from each end of the two wires.
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3
Line the wires up with the uncrimped RJ45 connector while looking at the connector from the top. Let one wire connect the first and third pins from the left--the one and three positions--while the other connects the second and sixth pins--the two and six positions.
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4
Use your crimping tool to crimp the connector closed on the wires. Twist the wires together if you wish, or use electrical tape to bind them and keep them manageable.
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Tips & Warnings
It doesn't matter which pair of wires you use to create your Ethernet loopback cable, so long as you connect the proper pins. when aligning the wires, make sure that you look at the connector from the flat side, not the side that has the retaining clip attached to it.
References
Resources
- Photo Credit ethernet image by Jaume Felipe from Fotolia.com
