Shielding against crosscoupled signals from other wires in acable.By keeping the two wires as close to each other as possible itensures both wires pick up nearly the same amount of crosscoupledsignals from other wires in the cable, making it easy to remove ina differential amplifier with high common mode rejection at thereceiving end. In other words the crosscoupled signals from otherwires cancel out each other in twisted pair cables.