A channel plan and a corresponding test plan are implemented in connection with a plurality of nodes that communicate signals. An input signal can be divided into equal parts going around a ring clockwise and counterclockwise. The body of the plug is receivable by the receiving portion in at least two orientations such that in each of the at least two orientations, the electrical prongs extend outward from the housing, and one or more of the electrical contacts of the plug engage at least one of the first electrical contacts or at least one of the second electrical contacts.