Specifications

66
8.2.1 Transition Zone
A Region must be between 20 and 200 Nautical miles and within this region there will be a “Transition
zone” between 1 and 8 Nautical miles:
This zone is used for frequency transition so only one
frequency is changed at a time. There are defined
rules for how the AIS will behave through this zone.
The AIS will continuously monitor for its own position
and range to the regional areas defined. By entering
transition Zone of Region 1, frequency is changed on
the primary channel. The AIS is now sending the
primary frequency defined for each of the regions.
When the boundary for the Region 1 is crossed, the second frequency shall be changed. Then the primary
frequency for the old region (or default setting) is switched with the secondary frequency for the new
region. Then both frequencies have changed.
When entering another region, frequency transition is performed as described above with the frequencies
(settings) of the new region. When leaving a region, frequency transition is reset to perform the default
values.