Abstract: In a telephone communication system employing a lower spectral band and a higher spectral band for communication of voice and video, wherein the system includes a first line for carrying signals at both the first and the second spectral bands and a second line for carrying signals at only the second spectral band, and wherein capacitors are employed for connection of the second line to the first line for exclusion of DC at a signal splitter of the communication system, the system has a bypass DC signal path for an alternative connection of the second line to the first line in substitution for the connection of the capacitors. The bypass can be activated electronically and remotely to establish conditions for the conduction of test of the signal carrying lines.