This is important for sending and receiving information on patch cables. Once you have completed two ends on a cable you can test it with the LAN tester. You hook up each end tot he LAN tester and push the button. You will see eight lights that should al light up if all wires are connected. You should also see that the wires are parallel.
Parallel means that each wire is connected to the right wire.
If you do not see all wires light up or you see that it is not parallel, you must cut off an end and try again.