Parameter

Number of bits

Description

Message ID

6

Identifier for this message 6; always 6.

Repeat Indicator

2

Used by the repeater to indicate how many times a message has been repeated.
0 - 3; default = 0; 3 = do not repeat any more.

Source ID

30

MMSI number of source station

Sequence Number

2

0 - 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. Should be zero

DAC

10

Destination Area Code.
Default: 421

FI

6

Function Identifier
Default: 16

Sub Function Identifier

16

Default: 0

Direction

12

0 -359 (deg)

Direction to the ship which sent warning.

Distance

10

0 - 127 (1/10 nm)

Distance to the ship which sent warning.

Warning Level

2

0 - 3

0:Release from caution
1: Caution
2: Warning

Arrival Time

8

0 - 256 (1/10 minutes)

Estimated arrival time to the future position a collision.

Spare

4

For future use. Should be zero.

TOTAL OF BITS.

136

Occupies 1 slot.