Question 18C4

Digital Selective Calling (DSC) Distress calls are part of the Global Maritime Distress and Safety System (GMDSS) protocol, designed for efficient and reliable distress alerting. The automatic repetition of an unacknowledged DSC Distress call is regulated to ensure that a distress alert is eventually received and acknowledged without unduly saturating the airwaves. A delay of **3.5 to 4.5 minutes** allows sufficient time for a coast station or another vessel to receive, process, and acknowledge the initial distress alert. If no acknowledgement is received within this specific window, the system is designed to automatically re-transmit the call. This delay is a careful balance: it's long enough to prevent immediate, unnecessary re-transmissions but short enough to ensure critical distress information is re-broadcast promptly if not acknowledged, significantly increasing the chances of a successful alert and subsequent rescue. Options A, B, and D do not represent the precise, standardized GMDSS timing for DSC Distress call repetition.