Coupling a signal to and/or from a twisted pair cable

摘要

A coupling unit for coupling a voltage signal to and/or from a twisted pair cable by non-contact coupling with twisted pairs in the twisted pair cable comprises at least a first electrode 120a and a second electrode 120b. The electrodes provide a capacitive coupling between a first twisted pair 1,2 and a second twisted pair 5,6 such that the signal propagates along the cable between the two twisted pairs. The electrodes may be electrically isolated from the voltage signal generator by use of a balun (122, fig.6) and the voltage signal may be converted into a differential voltage signal for coupling to the electrodes. The signal may be used to determine patch cable interconnections in a communications network such as a LAN or may be used to perform reflectometry tests on the cable.