AIS transponders must be programmed with the MMSI number, among other data. MMSI is the unique identifier for each ship.
This number will be used for all communications equipment such as radio beacon and DSC radio.
For Spanish vessels, the procedure to obtain the MMSI is done through Dirección General de Marina Mercante.
In the case of the class B transponder AIS CTRX by Trueheading, the certification number is 57.0003