The thesis advanced in this text is that one can only understand that which are thought of and understood as « communications phenomena » if a number of analytic threads are untangled and then recontructed historically. The example of the « cable plan » allows one to see how, on the one hand, a decision whose interpretation is contingent upon the result of a process and of a logic that will be later put to work. Yet, on the other hand, in following one of these dimensions , that of symbolic politics, one can at the same time interpret this process in the long term and mark the discontinuities that lie beneath the continuities. That being the case, « communications phenomena » can be siezed as a moment in the historical evolution of symbolic politics or as the manifest cumulation of a « long 19th century ». One thus initiates a social history of communications that may also contribute to a history of the present.