DSC

DSC - Digital Selective Calling - is basically a calling system under GMDSS.

Each call consists of a packet of digitized information with one of four priorities:

• Distress

• Urgency

• Safety or

• Routine

The messages can be sent to 'All stations', to a single station, or to a group of stations using the special MMSI number (Maritime Mobile Selective Identity). Emergency messages are sent automatically to all stations.

In addition to MMSI at the source and destination stations, different information can be attached to the call. For example, a message regarding Distress will contain the following information:

• Ship Identity (MMSI)

• Time of transmission

• What is the reason for the message

• The position of the ship

When the ship is equipped with DSC equipment, the ship's radio operator must ensure that it is correctly setup. Ships regularly test their DSC equipment on the 2187.5 kHz frequency with the nearest coastal radio station. The call is made as an 'Individual' call with the priority 'Safety'.

Aasiaat Radio's MMSI number is 00 331 1000

Note that ships that have not connected GPS to the DSC equipment should update the position at least on each watch.