Which types of automated radio broadcasts have MMSI numbers embedded?

• A. AIS (Automated Identification System)
• B. DSC (Digital Selective Calling)
• C. 406 EPIRB (Emergency Positioning Indicating Radio Beacon)
• D. All of the above

Answer: (D)

MMSI numbers serve as the vessel’s unique identity across automated radio broadcasts. In AIS, every message carries the vessel’s MMSI, making the identity explicit in the data being transmitted. In DSC, calls are addressed by MMSI, so the message payload inherently includes the MMSI of either the caller or the target, embedding the identity within the digital communication. For 406 EPIRB beacons, the beacon broadcasts a unique beacon ID, and responders can link that ID to the vessel’s MMSI through the registry, allowing the vessel’s identity to be identified and correlated with the distress signal. Because each of these systems ties communications to a vessel identity via an MMSI, all of them involve MMSI numbers embedded or associated with the automated broadcasts.