Text description

Introduction/Additional information: 

14.1 This message provides a text description in combination with other AIS Application-Specific Message.

14.2 This message can be broadcast or addressed, but must be the same as the main message that it is linked to.

14.3 The Message Linkage ID is used to link the Text Description message to another AIS Application-Specific Message (e.g., Area Notice or Route Information). The same source MMSI must be used to send both the main message and Text Description message.

14.4 Up to 5-slot messages can be created, however messages greater than 3 slots should be avoided.

Registrant: 
IMO Circ. 289
Message number: 
6
DAC: 
1
FI: 
30
State: 
in force
Number of slots (max): 
5
Permitted as from: 
01/06/2010
Details: 

Table 14.3

Text description - (addressed)

 

Parameter

No 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.

0 - 3

0 = default

3 = do not repeat anymore

Source ID

30

MMSI number of source station.

Sequence Number

2

0 - 3; refer to § 5.3.1, Annex 2 of ITU-R M.1371-3.

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. Set to zero.

IAI

16

DAC = 001; FI = 30

(See Rec. ITU-R M.1371-3, Annex 5, § 2.1.

Message Linkage ID

10

Used to link the Text Description message with a main message. The Connection ID and source MMSI MID uniquely identifies the main message.

1 - 1,023

0 = not available = default

Text String

6 - 930

Free text 1 - 155 characters 6-bits ASCII). If applicable, recommended to use IMO Standard Marine Communication Phrase (SMCP) (see IMO A.918(22)).  Number of slots used should be minimized, refer to Table 14.4.

Spare

0

Not used. Set to zero.

Total

104 - 1028

Occupies 1 - 5 slots (see Table 14.4).

 

Table 14.4

Number of slots if sent as an addressed message

 

Number of characters in the message

1-6

7-43

44-81

82-118

119-155

Number of slots used

1

2

3

4

5