Of all the characteristics of LAN cable operation, crosstalk has the greatest effect on cable performance.
Crosstalk is undesirable signal transmission from one cable pair to another nearby pair.
Like electrical noise from outside sources, crosstalk can cause communication problems in networks. Of all the characteristics of LAN cable operation, crosstalk has the greatest effect on network performance. The Fluke DSP-100 test tool used by SMSU measures crosstalk by applying a test signal to one cable pair and measuring the amplitude of the crosstalk signals received by the other cable pairs. The crosstalk value is computed as the difference in amplitude between the test signal and the crosstalk signal when measured from the same end of the cable. Higher NEXT values correspond to less crosstalk and better cable performance.