Message 13 should be used as an acknowledgement of up to four Message 12 messages received (see § 5.3.1, Annex 2) and should be transmitted on the channel, where the addressed message to be acknowledged was received. These acknowledgements should be applicable only to the VHF data link (see § 5.3.1, Annex 2). Other means must be employed for acknowledging applications. 56 Parameter Number of bits Description 6 Message ID Identifier for Messages 7 or 13 7 = binary acknowledge 13 = safety related acknowledge 2 Repeat indicator Used by the repeater to indicate how many times a message has been repeated. See § 4.6.1, Annex 2; 0-3; 0 = default; 3 = do not repeat any more 30 Source ID MMSI number of source of this acknowledge (ACK) 2 Spare Not used. Should be set to zero. Reserved for future use 30 Destination ID1 MMSI number of first destination of this ACK 2 Sequence number Sequence number of message to be acknowledged; 0-3 for ID1 30 Destination ID2 MMSI number of second destination of this ACK; should be omitted if no destination ID2 2 Sequence number Sequence number of message to be acknowledged; 0-3; should be omitted if for ID2 no destination ID2 56 (end) Parameter Number of bits Description 30 Destination ID3 MMSI number of destination of this ACK; should be omitted if no destination ID3 2 Sequence number Sequence number of message to be acknowledged; 0-3; should be omitted if for ID3 no destination ID3 30 Destination ID4 MMSI number of fourth destination of this ACK; should be omitted if no destination ID4 2 Sequence number Sequence number of message to be acknowledged; 0-3. Should be omitted if for ID4 there is no destination ID4 72-168 Number of bits 3.6 Message 8: Binary broadcast message This message will be variable in length, based on the amount of binary data. The length should vary between 1 and 5 slots. TABLE 57 Parameter Number of bits Description Message ID 6 Identifier for Message 8; always 8 2 Repeat indicator 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 30 Source ID MMSI number of source station
Message 13 should be used as an acknowledgement of up to four Message 12 messages received (see § 5.3.1, Annex 2) and should be transmitted on the channel, where the addressed message to be acknowledged was received. These acknowledgements should be applicable only to the VHF data link (see § 5.3.1, Annex 2). Other means must be employed for acknowledging applications. 56 Parameter Number of bits Description Message ID 6 Identifier for Messages 7 or 13 7 = binary acknowledge 13 = safety related acknowledge 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; 0 = default; 3 = do not repeat any more Source ID 30 MMSI number of source of this acknowledge (ACK) Spare 2 Not used. Should be set to zero. Reserved for future use Destination ID1 30 MMSI number of first destination of this ACK Sequence number for ID1 2 Sequence number of message to be acknowledged; 0-3 Destination ID2 30 MMSI number of second destination of this ACK; should be omitted if no destination ID2 Sequence number for ID2 2 Sequence number of message to be acknowledged; 0-3; should be omitted if no destination ID2 56 (end) Parameter Number of bits Description Destination ID3 30 MMSI number of destination of this ACK; should be omitted if no destination ID3 Sequence number for ID3 2 Sequence number of message to be acknowledged; 0-3; should be omitted if no destination ID3 Destination ID4 30 MMSI number of fourth destination of this ACK; should be omitted if no destination ID4 Sequence number for ID4 2 Sequence number of message to be acknowledged; 0-3. Should be omitted if there is no destination ID4 Number of bits 72-168 3.6 Message 8: Binary broadcast message This message will be variable in length, based on the amount of binary data. The length should vary between 1 and 5 slots. TABLE 57 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
R-REC-M.1371-5-201402-I!!MSW-E.docx