• The loop area between the wires (which determines the magnetic coupling into the signal) is reduced as much as physically possible.
• The directions of current generated by a uniform coupled magnetic field is reversed for every twist, canceling each other out.

RJ-45 (Registered Jack 45) is a physical interface often used for terminating twisted pair type cables. "RJ" stands for Registered Jack which is part of the United States Code of Federal Regulations. It has eight "pins" or electrical connections per connector.

It is usually used with standards like TIA-568B, which define the wiring pinout:

RJ-11 (or RJ11) is a physical interface often used for terminating telephone wires. RJ stands for registered jack, which is part of the United States Code of Federal Regulations. It has six positions with two pins (electrical connections) installed at positions 3 and 4. RJ-14 (or RJ14) indicates that there is a second pair for an additional line on pins 2 and 5. RJ-12 (RJ12) or RJ-25 (RJ25) indicate that there is a third pair on pins 1 and 6. The connectors are commonly (but unofficially) designated as 6P2C, 6P4C, and 6P6C (where 'P' stands for 'positions' and 'C' stands for 'conductors'), respectively.

This type of plug has a hinged locking tab that must be depressed to remove the plug from the wall jack. The disadvantage lies in the lightweight construction of the plug. If the plug were unhooked from the jack, and cord pulled free, the locking tab is subject to catching on the cord, desk, carpet, etc. and breaking it off. Some higher quality cables incorporate a plastic sleeve over the tab to prevent this.