DSC radio, when combined with the Coast Guard’s Rescue 21 initiative, can be a great advantage for boaters. For starters, it can greatly reduce the time it will take the Coast Guard to find you in case of an emergency. In other words, it can take the search out of search and rescue! Secondly, in case of emergency, your radio will tell the Coast Guard vital information about you: information like the name and description of your boat, exactly where you are located, even who to contact in case of emergency.  The system is automatic; it will continue to transmit information even if you can’t man your radio.  Finally, it’s simple to use. Even guests on your boat can make this easy call for help in a crisis.

 Here’s how Digital Selective Calling works. You’re out on the water. Blue sky, slight breeze, a perfect boating day.   Then all of a sudden something goes wrong. Very wrong. It could be a fire, an accident or a medical emergency of some kind.   You need help, and you need it fast!   Don’t panic.  Help is as close as your DSC/VHF radio. 

 On the front of the radio you’ll see a red Distress button. Just press that button. This is where DSC and Rescue 21 take over. Once you press the distress button, your radio sends a digital signal over Channel 70.  That signal goes to the Coast Guard, but it also goes out to all boats within range that have DSC/VHF radios. The radio will continue to send the message until someone acknowledges it.  This message is fast (only 1/3 of a second), accurate, complete and automatic.  It will continue to broadcast even if the skipper is incapacitated.

 Your distress signal alerts the Coast Guard Watchstander that you’re in trouble.  The digital information tells the Coast Guard the exact location of your boat (latitude and longitude) as well personal information and a description of your boat. The Watchstander will acknowledge your message, and your radio will automatically switch to Channel 16 so you can talk directly to the Coast Guard. In addition, other nearby vessels will be notified where you are and that you are in a crisis.  You can rest assured that help is on the way, thanks to Digital Selective Calling and Rescue 21.

 In order for this system to function correctly, though, it is crucial that it be properly configured, so now we’re going to take a look at the basics of setting up and using a DSC/ VHF radio. For specific information, please always refer to your radio and or GPS user’s manual.

 Radio Options Rundown 
There are all kinds of radios on the market today for the recreational boater. In order to make sure that you get the type of radio that best fits your needs, it is important to understand the 3 classes of radios.

 The most expensive is Class A. This type of DSC/VHF radio has 2 receivers and can receive DSC signals while transmitting and receiving. This type of radio is the most expensive and required on ships.

 International Class D radios also have 2 receivers.  One channel is always tuned to channel 70, the DSC distress channel, so that you can receive DSC signals even if you’re also receiving signals on another channel. They start around $200 and have full DSC options.

 The third option, Class 1SC101 & US Class D, has only one receiver.  That means if you’re receiving signals on another channel, you could miss DSC signals coming in on channel 70.   As the least expensive option, this class of radios also has fewer features and limited DSC capabilities.

 The Coast Guard recommends recreational boaters use the International Class D radio.

 Putting It All Together

             In order to take advantage of your DSC/VHF radio, you will need 5 things.

1.      A DSC/VHF radio

2.      An MMSI (Maritime Mobile Service Identity) Number

3.      A GPS or Loran C Receiver

4.      A Two wire connection to your GPS (NMEA In and Out)

5.      A knowledge of your DSC Radio

 The GPS receiver

            To ensure a GPS is compatible with the DSC/VHF radio you’ll need to verify that the GPS supports NMEA. If you don’t see this information on the packaging, you can look in the user manual under specifications. The specifications should say NMEA 0183 Input and NMEA output or they may say “supports DSC.”  This means it displays position data from a DSC-capable VHF radio.

The MMSI Number

            The MMSI number is the most important step in making sure your radio and GPS will work with the Rescue 21 program. Please note that your DSC radio will not work correctly without an MMSI number. You can get an MMSI number by going to http://www.boatus.com/mmsi/. This service is free and it only takes a few minutes. Your MMSI number will be a nine digit number that contains your boat and emergency contact information.  You can also use your MMSI number to hail other vessels, and other vessels can use it to contact you.  Think of it as a phone number for your DSC/VHF radio.   But its most important feature is to send information about your boat to the Coast Guard when someone activates the Distress button. Once you get an MMSI number, you’ll need to program it into your DSC/VHF radio.

Connecting the Pieces

Now that you’ve got all the right equipment, it’s time to hook it all up and test it out.

Once you’ve properly installed your DSC/VHF radio and your GPS, you’ll need to connect a wire from the radio to the GPS. These wires will be labeled “NMEA Device In” and “NMEA Device Out.”  Connect the “NMEA in” on the radio to the “NMEA out” on the GPS.  Then connect the “NMEA out” from the radio to the “NMEA in” on the GPS.  Some systems may also require you to connect a ground wire between the two systems.  In addition, you may need to configure your GPS to communicate with your DSC/VHF radio.  You can do this by changing the communication settings in the GPS.  Refer to your manual for details.

That should be it. Once your equipment is correctly hooked up, the final step will be testing the system to make sure everything’s working properly.

Testing the system.

Once your MMSI number is programmed into the radio and the radio and the GPS are linked, you will be able to see the MMSI number displayed on the radio display and you will be able to see your Lat/Long position displayed on your radio as well.

 Here it gets a little bit tricky.  You can’t just press the distress button to test it. You’ll need to get the MMSI number for either a friend’s radio or a shore station.  Enter that number into your radio. Choose a working channel, but NOT channel 16. Select Routine Call from your radio. Now press either enter or send.  Your radio should indicate the call was sent and indicate that whomever you called received your call. Finally, it will switch to the working channel you chose. You can now communicate with the other station to ensure that everything is working properly.

 Dos and Don’ts, Wills and Won’ts – Wrapping it Up

 We know all these letters and numbers may have been a bit confusing, so let’s go through the key points one more time – exactly what your DSC/VHF radio will and won’t do for you.

 Remember -- to take advantage of the Global Distress and Safety System your vessel must be equipped with a radio that has DSC.

DSC/VHF radios WILL:

·        Have a One-Button Distress signal that sends out the vessel's unique MMSI number and, if properly connected to a GPS or Loran, the vessel's latitude and longitude position.

·        Continue sending the distress signal even if the captain is incapacitated.

·        Allow a non-experienced VHF user to send, with the press of one button, a goof-proof continuous distress message.

·        Privately hail another DSC equipped vessel or shore station, with a known MMSI number.   Consider your MMSI your “VHF phone number."  This means you won’t have to monitor high traffic channels just for a hail from your boating buddy. It even "rings" your radio like to a telephone, notifying you that you have a call -- then switches you automatically to the channel where your buddy is waiting.

·        If your radio is properly connected to a Loran or GPS, a "Polling" feature transmits your vessel's position, in a digital display that can be monitored by a DSC-equipped home station, fleet station or boat.

·        Function exactly like all other regular VHF radios.

 On the other hand, DSC/VHF radios WILL NOT:

·    Be monitored by the U.S. Coast Guard in all areas until that area's Rescue 21 system is operational.   However, other DSC equipped vessels in the area may still receive your distress call.

·    Provide private radio-to-radio voice communication. After the "private" digital hail, DSC radios automatically switch to an open VHF channel for voice communications. You’ll then talk using the active working channel.

 Now you can rest assured that in case of an emergency you have the equipment and knowledge to know help is on the way.  For more information on this subject and other DSC features, please visit http://www.boatus.com/MMSI.

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