Which of the following statements concerning MMSI is true?

The statement that all MMSI (Maritime Mobile Service Identity) numbers are 9 digits and contain an MID (Maritime Identification Digits) is accurate. MMSI numbers are essential for identifying ships, coast stations, and group calls in maritime communication. They consist of nine digits, where the first three digits represent the MID, indicating the country or mobile maritime service provider the vessel is affiliated with.

This structure is standardized to ensure consistency across international maritime communication systems and enhance identification processes. Each MMSI number uniquely identifies a station, which is crucial for safety and regulatory compliance in maritime operations. It is also important for automated distress messaging and vessel tracking systems.

The other statements do not conform to the established guidelines regarding MMSI numbers. For example, coast station MMSI numbers specifically follow different protocols and do not necessarily begin with the digit 4, and while ship station MMSI numbers are always 9 digits, group MMSI numbers can also start with digits other than just two zeros.