ASM Message 0 may contain encapsulated AIS Messages 6, 8, 12, 14, 21, 25 or 26. Acknowledgement is not supported for addressed messages. This message type is for terrestrial use only.
The encapsulated message may or may not be transmitted on AIS1 or AIS2 channels.
If the encapsulation repeats a Message that was transmitted on AIS1 or AIS2 channel, the encapsulation and transmission of messages shall be performed as soon as possible, according to configuration, after receiving the relevant messages which are required to be retransmitted.
The communication state of the encapsulated message shall always be set to zero at encapsulation.
The receiving station shall output all received encapsulated AIS Messages at the PI immediately after reception. Scheduled broadcast message is defined in Table 26.
Table 26
Broadcast automatic identification system application specific message
|
Parameter |
Number of bits |
Description |
|---|---|---|
|
Message ID |
4 |
0 – Selected AIS messages that are output at receiving mobile station PI by using VDM sentence with no communication state. |
|
Retransmit flag |
1 |
0 (reserved for future use). |
|
Repeat indicator |
2 |
Used by the repeater to indicate how many times a message has been repeated. 0 – 3; 0 = default; 3 = do not repeat any more. |
|
Session ID |
6 |
The Session ID associates the VDL transmission with a specific PI transaction. |
|
Source ID |
32 |
The Unique Identifier of the transmitting station as described in § A1-2.4. |
|
Data count |
11 |
Size of actual data in Application Data field in bits, excluding padding bits range: from 1 to maximum data count. |
|
Application data |
1 slot: 296 / 200 |
Content is encapsulated AIS Messages that are channelled through ASM Channels. Receiver is expected to be ASM-capable mobile station where the ASM-box would relay the encapsulated AIS messages to local presentation interface. The encapsulated AIS Messages would then be output at the PI using VDM sentence. The arrangement would thus be compliant with existing nav presentations. Application data as specified by the ASM Identifier. The available length of the binary data is specified by the Link Id. |