1

Position report

Scheduled position report;
(Class A shipborne mobile equipment)

1

SOTDMA, RATDMA, ITDMA⁽¹⁾

SOTDMA

M

2

Position report

Assigned scheduled position report; (Class A shipborne mobile equipment)

1

SOTDMA⁽⁹⁾

SOTDMA

M

3

Position report

Special position report, response to interrogation; (Class A shipborne mobile equipment)

1

RATDMA⁽¹⁾

ITDMA

M

4

Base station report

Position, UTC, date and current slot number of base station

1

FATDMA^{(3) (7)}, RATDMA⁽²⁾

SOTDMA

B

5

Static and voyage related data

Scheduled static and voyage related vessel data report; (Class A shipborne mobile equipment)

4⁽⁵⁾

RATDMA, ITDMA⁽²⁾

N/A

M

6

Binary addressed message

Binary data for addressed communication

4

RATDMA⁽¹⁰⁾, FATDMA, ITDMA⁽²⁾

N/A

M/B

7

Binary acknowledgement

Acknowledgement of received addressed binary data

1

RATDMA, FATDMA, ITDMA⁽²⁾

N/A

M/B

8

Binary broadcast message

Binary data for broadcast communication

4

RATDMA⁽¹⁰⁾, FATDMA, ITDMA⁽²⁾

N/A

M/B

9

Standard SAR aircraft position report

Position report for airborne stations involved in SAR operations, only

1

SOTDMA, RATDMA, ITDMA⁽¹⁾

SOTDMA ITDMA

M

10

UTC/date inquiry

Request UTC and date

3

RATDMA, FATDMA, ITDMA⁽²⁾

N/A

M/B

11

UTC/date response

Current UTC and date if available

3

RATDMA, ITDMA⁽²⁾

SOTDMA

M

12

Addressed safety related message

Safety related data for addressed communication

2

RATDMA⁽¹⁰⁾, FATDMA, ITDMA⁽²⁾

N/A

M/B

13

Safety related acknowledgement

Acknowledgement of received addressed safety related message

1

RATDMA, FATDMA, ITDMA⁽²⁾

N/A

M/B

14

Safety related broadcast message

Safety related data for broadcast communication

2

RATDMA⁽¹⁰⁾, FATDMA, ITDMA⁽²⁾

N/A

M/B

15

Interroga­tion

Request for a specific message type (can result in multiple responses from one or several stations)⁽⁴⁾

3

RATDMA, FATDMA, ITDMA⁽²⁾

N/A

M/B

16

Assign­ment mode command

Assignment of a specific report behaviour by competent authority using a Base station

1

RATDMA, FATDMA⁽²⁾

N/A

B

17

DGNSS broadcast binary message

DGNSS corrections provided by a base station

2

FATDMA⁽³⁾, RATDMA⁽²⁾

N/A

B

18

Standard Class B equipment position report

Standard position report for Class B shipborne mobile equipment to be used instead of Messages 1, 2, 3⁽⁸⁾

1

SOTDMA, ITDMA^(1),

CSTDMA

SOTDMA, ITDMA

M

19

Extended Class B equipment position report

Extended position report for class B shipborne mobile equipment; contains additional
static information⁽⁸⁾

1

ITDMA

N/A

M

20

Data link manage­ment message

Reserve slots for Base station(s)

1

FATDMA⁽³⁾, RATDMA

N/A

B

21

Aids-to-navigation report

Position and status report for aids-to-navigation

1

FATDMA⁽³⁾, RATDMA⁽²⁾

N/A

M/B

22

Channel manage­ment⁽⁶⁾

Management of channels and transceiver modes by a Base station

1

FATDMA⁽³⁾, RATDMA⁽²⁾

N/A

B

23

Group assignment command

Assignment of a specific report behaviour by competent authority using a Base station to a specific group of mobiles

1

FATDMA, RATDMA

N/A

B

24

Static data report

Additional data assigned to an MMSI

Part A: Name
Part B: Static Data

4

RATDMA, ITDMA,

CSTDMA,

FATDMA

N/A

M/B

25

Single slot binary message

Short unscheduled binary data transmission (Broadcast or addressed)

4

RATDMA, ITDMA,

CSTDMA,

FATDMA

N/A

M/B

26

Multiple slot binary message with Communi­cations State

Scheduled binary data transmission (Broadcast or addressed)

4

SOTDMA, RATDMA, ITDMA

SOTDMA,
ITDMA

M/B