Digital Selective Calling (DSC) is primarily used to initiate distress calls to shore stations and other vessels via your DSC radio. All DSC-equipped shore stations and vessels will hear your distress signal as an alarm. It will be repeated every 4 minutes until acknowledged. A DSC alert signal has a 15% greater range than a voice transmission and therefore is more likely to reach a vessel or rescue center. The DSC radio provides recipients of your emergency call with:
Your Unique MMSI Number
Your Precise Position
The Nature of your Distress
In a potentially dangerous situation, a DSC alert signal is the quickest way to initiate emergency communications with ships and rescue coordination centers. DSC saves vital time by allowing you to speak to the emergency authorities and plan your next move.
It is critical that your DSC radio is properly installed and that you are licensed to use it. Without these two things, you will not benefit from DSC. MMSI’s are important in the UK as they are assigned as part of the ship's radio licensing procedure. Without an MMSI programmed radio, you cannot access full DSC functions. With the wrong MMSI number entered, you will be using the radio illegally and putting your life at risk.
If integrated with GPS navigational equipment (highly recommended), a vessel's position and time of transmission are automatically included in the DSC distress and urgency alerts, an important point when you find yourself in trouble. If your DSC is not linked to a GPS, the manual input of your coordinates is required. When linked to a GPS, it is simply a case of pressing the red DSC button to summon help.
All large vessels and almost all Coastguards over Europe are fully-equipped for DSC and will respond instantly. GMDSS is an automatic, worldwide system and can be used anywhere, avoiding possible language barriers. If you are in trouble, DSC allows you to call every other radio in range, simultaneously.