Ethernet Loopback connector

Occasionally I need for a network card to operate as a live network connection, without it actually being connected to a network. Typically for testing purposes, I need a quick and easy way to make a loopback connector. Small enough to keep in my Pocket. The following is a quick "how to" for making an Ethernet loopback connector.

To create a loopback plug, cross pin 1 (TX+) and pin 3 (RX+) together, and cross pin 2 (TX-) and pin 6 (RX-) together. You need the following equipment to create the loopback:

• A 6-inch long CAT5 cable
• An RJ-45 connector
• A crimping tool

When you create and then test a physical loopback, you are testing the RJ-45 interface of the NIC.