Text telegram using 6-bit ASCII
Introduction/Additional information:
This IFM should be used by a ship or base station to send 6-bit ASCII text telegram to other AIS stations. The text telegram can be sent with either binary message 6 or 8. The acknowledge required flag should not be set when using the broadcast message 8.Replaced by ITU-R.M.1371-3
Registrant:
ITU-R.M.1371-1
DAC:
1
FI:
0
State:
replaced
Number of slots (max):
5
Permitted as from:
01/01/1998
Not to be used after:
31/05/2007
Details:
TABLE 25
International function message 0 using Message 6, addressed binary message
International function message 0 using Message 6, addressed binary message
| Parameter | Number of bits | Description |
|---|---|---|
| Message ID | 6 | Identifier for Message 6; always 6 |
| 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 station |
| Sequence number | 2 | 0-3; see § 5.3.1, Annex 2 |
| Destination ID | 30 | MMSI number of destination station |
| Retransmit flag | 1 | Retransmit flag should be set upon retransmission: 0 = no retransmission = default; 1 = retransmitted |
| Spare | 1 | Not used. Should be zero |
| DAC | 1 | International DAC = 110 = 00000000012 |
| FI | 0 | Function identifier = 010 = 0000002 |
| Acknowledge required flag | 1 | 1 = reply is required 0 = reply is not required |
| Message sequence number | 11 | Sequence number to be incremented by the application. All zeros indicates that sequence numbers are not being used |
| Text message | 924 | 6-bit ASCII as defined in Table 14. When using this IFM, the number of slots used for transmission should be minimized taking into account the table below |
| Spare bits | N | Formula for inserting for spare bits |
| Total number of application data bits | 936 |
The following table gives the number of 6-bit-ASCII characters, 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 characters to the numbers given, if possible:
| Number of slots | Maximum number of 6-bit ASCII characters | |
| Addressed binary message, 06 | Broadcast binary message |
|
| 1 | 8 | 14 |
| 2 | 46 | 51 |
| 3 | 83 | 88 |
| 4 | 120 | 126 |
| 5 | 158 | 163 |