Collision alarm

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.