Kongsberg Seatex AIS 100 Instruction Manual page 67

Seatex AIS 100 Instruction Manual, rev. 5
NOTE 3
NOTE 4
NOTE 5
the same Sequential Message Identification number. This number is
used to link the separate sentences containing portions of the same
encapsulated data. This allows for the possibility that other sentences
might be interleaved with the message sentences that, taken
collectively, contain a single message 8 or 14. This number also links
a future ABK-sentence acknowledgement to the appropriate BBM-
sentence. (See ABK, NOTE 4.)
The AIS channel that shall be used for the broadcast: 0 = no broadcast
channel preference, 1 = Broadcast on AIS channel A, 2 = Broadcast
on AIS channel B, 3 = Broadcast two copies of the message – one on
channel A and another sent on channel B.
This is the content of the "binary data" parameter for ITU-R M.1371
message 8 or the "Safety related Text" parameter for message 14. The
first sentence may contain up to 58 "6-bit" symbols (348 bits). The
following sentences may contain up to 60 "6-bit" symbols (360 bits),
if fields 4 and 5 are unchanged from the first sentence and set to null.
The actual number of "6-bit" symbols in a sentence must be adjusted
so that the total number of characters in a sentence does not exceed
the "82-character" limit.
To encapsulate, the number of binary bits must be a multiple of six. If
it is not, one to five "fill bits" are added. This parameter indicates the
number of bits that were added to the last 6-bit coded character. This
value shall be set to zero when no "fill bits" have been added. This
cannot be a null field.
LRI – Long-Range Interrogation
The long-range interrogation of the AIS is accomplished through the
use of two sentences. The pair of interrogation sentences, a LRI-
sentence followed by a LRF-sentence, provides the information
needed by an AIS to determine if it must construct and provide the
reply sentences (LRF, LR1, LR2, and LR3). The LRI-sentence
contains the information that the AIS needs in order to determine if
the reply sentences need to be constructed. The LRF-sentence
identifies the information that needs to be in the reply sentences.
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External interfaces