🔍 Key Concepts
• MMSI (Maritime Mobile Service Identity) structure for different types of stations
• How MID (Maritime Identification Digits) is used in ship, coast, and group MMSIs
• Differences between ship station, coast station, and group station MMSI formats
💭 Think About
• For each answer choice, picture what a valid MMSI for that station type would look like and where the MID appears, if at all.
• Ask yourself: which station type normally starts with one or more zeros before the MID, and which station type starts directly with the MID?
• Consider whether group MMSIs are structured the same way as individual ship or coast station MMSIs, or if they have a distinctive pattern.
✅ Before You Answer
• Verify in ITU/USCG guidance how a ship station MMSI is formatted, including whether it starts with a zero and how the MID is placed.
• Check the required pattern for a coast station MMSI: 9 digits, and where the zeros and MID must appear.
• Confirm whether group MMSI numbers begin with a leading zero, with the MID, or follow another distinct pattern before selecting your choice.