ITU-R Recommendation M.1371-1 describes the following types of AIS:

Class A
Shipborne mobile equipment intended for vessels meeting the requirements of IMO AIS carriage requirement.

Class B
Shipborne mobile equipment provides facilities not necessarily in full accord with IMO AIS carriage requirements. The Class B is nearly identical to the Class A, except the Class B:

  • Has a reporting rate less than a Class A (e.g. every 30 sec. when under 14 knots, as opposed to every 10 sec. for Class A)
  • Does not transmit the vessel's IMO number
  • Does not transmit ETA or destination
  • Does not transmit navigational status
  • Is only required to receive, not transmit, text safety messages
  • Is only required to receive, not transmit, application identifiers (binary messages)
  • Does not transmit rate of turn information
  • Does not transmit maximum present static draught
The AIS function is included as standard in MaxSea Time Zero. Any AIS receiver or transmitter can be connected to MaxSea Time Zero, allowing you to display AIS targets around your boat directly on the charts.