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June 19, 2006

New VHF Radio Technology Will Add Measure of Safety

Digital Selective Calling Radios Add New Safety Dimension To Recreational Boating...

A new technology in marine (VHF) radio technology now gives recreational boaters with one of the new marine radios, a connected GPS and a Maritime Mobile Service Identity (MMSI) number (which is free) programmed into the radio a way to identify the vessel in cases of emergency.
The MMSI is a unique nine (9) digit number that is assigned to a DSC radio station.  If the boater has a valid Federal Communications Commission (FCC) station license or plans to operate in international waters they need to contact the FCC to get an MMSI.  Otherwise, they can register with BoatU.S. by obtaining an MMSI Assignment form.  Forms are available on the BoatU.S. Web site  or by calling 1-800-563-1536.  Registration is also available from Seatow ( 

Some important points to consider are:

  • Each vessel you own needs to have a discrete MMSI to be properly identified.
  • The boater needs to keep their MMSI Assignment data current.

DSC technology makes a VHF radio function more like a telephone.  It allows boaters to send a digital call directly to another DSC equipped vessel or shore station. 

In an emergency, one push of a button and the DSC radio will send an automated digital distress alert consisting of your identification (MMSI), and position (if the radio is connected to a GPS or Loran unit) to other DSC equipped vessels and rescue facilities. 

As an additional benefit to boaters, makes it so you can also privately hail another DSC equipped vessel, or shore station, if you know their MMSI.  It is similar to having a VHF phone number which "rings" the radio called and then automatically switches you to a pre-determined working channel.

Rescue 21 is the Coast Guard system that will provide the May Day response capability described above.  For more details on the Rescue 21 System and its availability in your area visit .

The Global Maritime distress and Safety System (GMDSS) is the international system governing safety radio equipment on commercial ships. For more information on GMDSS visit