Termination scheme for twisted-wire pairs

摘要

A termination scheme for twisted-wire pairs for network communication systems, such as Fast Ethernet 100BaseTX, where the wires are electrically connected together and a single resistor is coupled in series between the junction of the wires and ground. A capacitor may also be coupled between the resistor and ground for DC isolation purposes. The single resistor preferably has a resistance equivalent to half of the common mode impedance between the unused pairs. The two wires of each pair are shorted together since there is no differential signal between the two wires. In this manner, two differential impedance resistors are eliminated, thereby reducing size and cost of the system without degrading performance.