Kongsberg Seatex AIS 100 Instruction Manual page 68

Seatex AIS 100 Instruction Manual, rev. 5
NOTE 1
NOTE 2
NOTE 3
NOTE 4
This is used to bind the contents of the LRI and LRF sentences
together. The LRF sentence shall immediately follow the LRI
sentence and use the same sequence number. The requestor process
shall increment the sequence number each time a LRI/LRF pair is
created. The sequencing process shall continuously increment. After
"9" is used, the process shall begin again at "0". If the LRI and LRF
sequence numbers are different, the Long-range interrogation is not
valid.
The control flag is a single character that qualifies the request for
information. The control flag affects the AIS unit's reply logic. The
control flag cannot be a null field. When the Control Flag is "0", the
AIS responds if either:
The AIS is within the geographic rectangle provided, and
The AIS has not responded to the requesting MMSI in the last
24 hours, and
The MMSI "destination" field is null.
or
The AIS unit's MMSI appears in the MMSI "destination" field
in the LRI sentence.
When the Control Flag is "1", the AIS responds if:
The AIS is within the geographic rectangle provided.
This is the nine-digit number that uniquely identifies the specific AIS
that should respond. This field is null when the interrogation is for a
geographic region. When addressing a specific AIS, it is not necessary
to provide the geographic co-ordinates of the region.
The geographic region being interrogated is a "rectangular" area
defined by the latitude and longitude of the north-east and south-west
corners. These fields should be null when interrogating a specific AIS.
(See note 2.)
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