By using the high resolution observation of Nan¿ay observatory, we have been able to identify the S burst emission on the planetary radio astronomy (PRA) records of Voyager. It is shown that the S bursts occur in two regions of the &PHgr;10-CML plane (S-IoB and S-IoA'C regions). In these regions the S burst emission is arranged into a pattern of repetitive features, drifting negatively. These features could be incomplete vertex late arcs. We show that the S burst pattern is distinct from the pattern of the Io-controlled emission. These results are discussed in the frame of Goldstein and Thieman's arc model.