Apparatuses and methods for coupling a signal to and from a twisted pair cable by non-contact coupling with twisted pairs in the twisted pair cable, such that the signal propagates along the cable between at least two of the twisted pairs. In particular, a coupling unit for coupling a voltage signal to and/or from such a cable, the coupling unit having a first electrode and a second electrode. The electrodes may be electrically isolated from a voltage signal generator and/or a voltage signal processor.