A system is provided for radio transmission between a central control and recording laboratory and spaced apart acquisition boxes in which relay transmission units are used for communicating with boxes which are directly inaccessible. It includes a centralization unit adapted for managing the exchanges of orders or data from the central laboratory with directly accessible boxes by means of a radio link in a first frequency band (f2), on the one hand and with the relay units by means of a radio link in another frequency band (f1). These latter manage the radio links with the inaccessible boxes by means of radio links at a frequency (f3) distinct from (f2). The relay units and the centralization unit are programmed for automatically managing the links between the central laboratory and any one of the boxes, whether they are direct or indirect, and, on the other hand, for reserving a part of the interrogation time of each box for the transmission of service data indicative of their correct operation.