This message will be variable in length, based on the amount of binary data. The length should vary between 1 and 5 slots.
|Parameter||Number of bits||Description|
|Message ID||6||Identifier for Message 8; always 8|
|Repeat indicator||2||Used by the repeater to indicate how many times a message has been repeated. See § 4.6.1, Annex 2; 0-3; default = 0; 3 = do not repeat any more|
|Source ID||30||MMSI number of source station|
|Spare||2||Not used. Should be set to zero. Reserved for future use|
|Binary data||Maximum 968||Application identifier||16 bits||Should be as described in § 2.1, Annex 5|
|Application data||Maximum 952 bits||Application specific data|
|Maximum number of bits||Maximum 1 008||Occupies up to 3 slots, or up to 5 slots when able to use FATDMA reservations.
For Class B “SO” mobile AIS stations the length of the message should not exceed 3 slots
For Class B “CS” mobile AIS stations should not transmit
Table 58 gives the number of binary data bytes (including application ID and application data), so that the whole message fits into a given number of slots. It is recommended that any application minimizes the use of slots by limiting the number of binary data bytes to the numbers given, if possible:
|Number of slots||Maximum binary data bytes|
These numbers also take into account bit stuffing.
Additional bit stuffing will be required for this message type. For details refer to transport layer, § 5.2.1, Annex 2.