A terahertz communications experiment involving the vertical coupling junction that is the main subject of this article, to complement the information that is given in Fig. 7 of the main text. A 4K video data signal is transmitted across the junction using a 300-GHz band carrier, and following demodulation, it is displayed on a 4K monitor in real-time. During the video, the link is interrupted by disconnecting the receiver, and it is subsequently replaced, restoring the signal.