Installation Manual

32 Issue 1 AIS Installation Manual
7.4 Message structures
Message structures are shown in the format used in IEC 61162-1
7.4.1 ABK - AIS addressed and binary broadcast acknowledgement
The ABK sentence is output by the transponder on the presentation ports in response to the
receipt of an ABM, AIR or BBM sentence. Its purpose is to inform the requesting device about
the success or failure of its request.
$--ABK,xxxxxxxxx,x,x.x,x,x*hh<CR><LF>
Type of acknowledgement
Message sequence number
M.1371 Message ID
AIS channel of reception
MMSI of the addressed AIS unit
7.4.2 ABM – AIS addressed binary and safety related message
This sentence is used to transmit M.1371 messages 6 (binary addressed) or 12 (addressed
safety related) via the AIS system by encapsulating the M.1371 message within one or more
AIS sentences.
$--ABM,x,x,x,xxxxxxxxx,x,xx,s—s,x*hh<CR><LF>
number of fill-bits
encapsulated data
M.1371 Message ID (6 or 12)
AIS channel
MMSI of the destination AIS unit
sequential message identifier
sentence number
total number of sentences
When the transponder receives an ABM sentence from an external device, it will return an ABK
sentence to indicate the success or failure of the transmission attempt.
7.4.3 ACA – AIS channel assignment message
$--ACA,x,llll.ll,a,yyyyy.yy,a,llll.ll,a,yyyyy.yy,a,x,xxxx,x,xxxx,x,x,x,a,x,hhmmss.ss*hh<CR><LF>
time of “in use” change
in-use Flag
information source
power level control
Tx/Rx mode control
channel B bandwidth
channel B
channel A bandwidth
channel A
transition zone size
region southwest corner longitude, E/W
region southwest corner latitude, N/S
region northeast corner longitude, E/W
region northeast corner latitude, N/S
sequence number
The ACA sentence is used both to send channel management information to the transponder
and to obtain channel management information from it.
7.4.4 ACK – Acknowledge alarm
This sentence is used to acknowledge an alarm condition.
$--ACK,xxx*hh<CR><LF>
alarm ID