Capability reply

Introduction/Additional information:

IFM 4 should be used by an application to reply (using Message 6) to a capability interrogation (IFM 3) function message. The reply contains the availability status of the application for each function identifier for the specified DAC.

The application should use an addressed binary message to reply to the interrogating application.

Permitted as from:

16/06/2007

Registrant:

ITU-R.M.1371-3

Physical link:

AIS

Message number (0=VDES-VDE):

DAC or VPFI:

FI / Message ID:

State:

in force

State link:

Capability reply [1]

Number of slots (max):

Last modified:

08/06/2021 - 12:01

Details:

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	10	International DAC = 1₁₀ = 0000000001₂
FI	6	Function identifier = 4₁₀ = 000100₂
DAC code	10	IAI, RAI or test
FI availability	128	FI capability table, pair of two consecutive bits should be used for every FI, in the order FI 0, FI 1, …..FI 63. First bit of pair: 0 = FI not available (default) 1 = FI available. Second bit of the pair: reserved for future use; should be set to zero
Spare	126	Not used, should be set to zero, reserved for future use
Total number of bits	352	The resulting Message 6 occupies 2 slots

FI capability table, pair of two consecutive bits should be used for every FI, in the order FI 0, FI 1, …..FI 63.
First bit of pair:
0 = FI not available (default)
1 = FI available.
Second bit of the pair: reserved for future use; should be set to zero