Explanation: Radio silence is a critical measure imposed to ensure that only essential communications related to a distress situation are transmitted, preventing interference with rescue efforts. The authority responsible for coordinating the distress, which is typically a Rescue Coordination Center (RCC) or the on-scene commander, is the only entity with the authority to impose and subsequently lift radio silence. Therefore, for normal working conditions to be restored, the RCC that initiated the radio silence must transmit a voice message, such as "SILENCE FINI" (or "SEELENCE FINI" phonetically), on the distress frequency. This signals that the distress situation has concluded or no longer requires restricted communications. Land Earth Stations (LES) are primarily gateways for satellite communications and do not have the authority to impose or lift general radio silence. Similarly, Public Correspondence Stations (PCS) are for routine public communication and have no role in distress coordination or the management of radio silence.