This can cause noise at both ends of a terminated cable. There are actually many forms of cross-talk which must be considered when building networks. NEXT can be addressed by termination technology, strict adherence to standard termination procedures, and use of quality twisted pair cables. NEXT-B is Near End Crosstalk at computer B. Thermal Noise Thermal noise, due to the random motion of electrons, is unavoidable but usually relatively small compared to our signals. AC line noise creates problems in our homes, schools, and offices.
Electricity is carried to appliances and machines by wires concealed in walls, floors, and ceilings.
Consequently, inside these buildings AC power line noise is all around us. If not properly prevented, power line noise can cause problems for a network. Ideally the signal reference ground should be completely isolated from the electrical ground. Isolation would keep AC power leakage and voltage spikes off the signal reference ground. But the chassis of a computing device serves as the signal reference ground, and as the AC power line ground.