Division 5.3 Extension of Message 21 with inland-specific type of AtoN

The parameter field ‘AtoN status’ is used for the extension of Message 21 with inland-specific type of AtoN.

The parameter field ‘AtoN status’ is organised in eight pages, of which page ID 0 is 0 = default, page ID 1 to 3 is for regional use and page ID 4 to 7 is for international use. The first three bits of the AtoN status filed defines the page ID, the remaining 5 bits contains the information of the page.

The region, in which page ID 1 to 3 is applicable is defined by the Maritime Identification Digits within the MMSI of the transmitting AIS AtoN station. Thus the bit coding of the 5 information bits in the AtoN status field is only applicable in this specific region.

As regards Union inland waterways page ID 1 of the AtoN status field contains the list of inland-specific type of AtoN used.

To set an inland-specific type of AtoN in Message 21 two steps have to be made. First the parameter ‘Type of aids-to-navigation’ in Message 21 needs to be set to ‘0 = Default, type of AtoN not specified’. Second, the parameter ‘AIS status’ needs to be set to page ID 1 and the appropriate code of the Inland-specific type of AtoN, as follows:

Msg 21 — AtoN status: