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Division 3.5.2 Application identifier for Inland AIS Application Specific Messages

United Kingdom

Original text. Later amendments are not shown.

The application specific messages consist of the AIS Class A mobile stations framework according Recommendation ITU-R M.1371 (message ID, repeat indicator, source ID, destination ID), the Application Identifier (AI = DAC + FI) and the data content (variable length up to a given maximum).

The 16-bit application identifier (AI = DAC + FI) consists of the following elements:

  1. (a)

    10-bit designated area code (DAC): international (DAC = 1) or regional (DAC > 1);

  2. (b)

    6-bit function identifier (FI) — allows for 64 unique application specific messages.

For the European harmonized Inland AIS Application Specific Messages the DAC ‘200’ is used.

In addition national (regional) DAC may be used in local ASM e.g. test pilots. Nevertheless it is strongly recommended to avoid the usage of regional ASM.