When there are electromagnetic waves in the space where the twisted pair is located, due to the effect of the twisted pair, the external electromagnetic waves will form interference currents with the same size and direction on the two cores of each pair, and this current will be transmitted to the balance transformers in the network equipment at both ends together with the signal current.

First of all, the two cores of the twisted pair of Chengjia cable will be connected to the primary winding, and the interference currents on the cores will cancel each other because of the grounding device in the center tap, so that the signal current can be transmitted to the secondary winding for amplification, shaping and processing, and finally restored to the required digital signal.

The main function of twisted pair is to reduce current interference and enhance signal transmission.