Icom M604A User manual

commercial ships and leisure craft visiting countries
outside of the US (includes Canada, the Bahamas,
and Mexico). You cannot go into another country
without FCC documentation.
If you’re staying within US waters, you can get an
MMSI from:
• Boat US: http://www.boatus.com/mmsi/
• U.S. Power Squadron:
http://www.usps.org/php/mmsi/home.php
• NOTE that the MMSI number is assigned to the vessel,
not the radio. The contact information must be up to
date and accurate.
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• Learn more about the wonderful safety advantages
of an Icom Class D VHF DSC radio by looking at the
following: www.boatus.com/foundation/dsc/player.html.
• Icom sets the standards for Class D DSC VHF radios.
Check out their complete line of marine radios at:
www.icomamerica.com/en/marine/
OPERATION GUIDE
CLASS D DSC
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DSC stands for “Digital Selective Calling” and
is a semi-automated method of establishing a
radio call; it has been designated by the In-
ternational Maritime Organization (IMO) as
an international standard for maritime MF, HF,
and VHF radio distress calls. It is part of the
Global Maritime Distress and Safety System
(GMDSS). DSC may eventually replace aural
watches on distress frequencies and will be
used to announce routine and urgent calls,
and distress alerts. DSC callouts may precede
maritime safety information broadcasts.
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DSC uses a digital signal to send a specic
set of information. To have it work, you need
the following:
• The vessel must be equipped with DSC
capable radio. It is best to have a Class D
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41078
‘voice chatter’ that would normally be heard on
VHF-FM voice hailing Channel 16.
Once the vessel has been registered for an MMSI
number, the information you provided will help in
the event that you’re sending a distress alert.
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The Coast Guard will use DSC to listen for
distress calls, initiate communications, and
announce urgent maritime information.
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All vessels operating on the high seas require a
MMSI number to participate in the Global Maritime
Distress and Safety System. There are four types
of MMSI numbers, each intended for a certain
purpose. The types are assigned to one of the
following:
• An individual vessel (ship station identity)
• Groups of vessels (group ship station identity)
• A shore-side facility (coast station identity)
• A group of shore-side facilities (group coast
station identities)
The FCC has jurisdiction over US agged ves-
sels. The FCC has a radio station license require-
ment and is the issuing authority for MMSIs for
all vessels subject to international law including
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Phone: [phone], www.icomamerica.com
M604A M504A M412

Once a DSC call is received, the receiving station
will use DSC protocol to acknowledge the call.
At this point, the parties will move to a working
frequency or channel.
Do not acknowledge distress calls. Doing so will
turn off the distress alert information from the
other vessel. Allow a shore station to respond. If
the shore station does not respond within FIVE
minutes, use the “relay” function of the radio
to forward the distress call to the USCG MMSI
003669999.
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DSC gives priority to Distress Alerts and can
send your position     

      

In non-emergency situations, boaters with DSC
radios can hail one another directly by punch-
ing in the unique, nine-digit MMSI number of the
vessel they wish to hail and make the call on
DSC Channel 70.
DSC minimizes the time necessary to establish
communications, and because the initial call
is made on Channel 70, this clears a lot of the
DSC radio as the new USCG regulations require.
• You must obtain a MMSI # (Maritime Mobile
Service Identity #) for your DSC radio from
Boatus.com. This is how others can identify it
is you making the DSC call.
• You must connect the DSC radio to a Global
Positioning System (GPS) in order for your
position to be sent with the DSC distress call.
Interconnect your radio to a GPS receiver
using a two-wire NMEA 0183 interface that is on
all DSC-equipped marine radios and on most
GPS receivers. Refer to your GPS manual for
instructions and the USCG web site for updates:
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• The system should be tested. To test the
system, do  press the distress button! You
will need to determine the MMSI number of a
friend or local shore station or use the USCG
test MMSI # when making a test call. To make
a test call enter the MMSI #. Use the DSC
calling Channel 70. Select a working channel
(NOT Channel 16), use a routine priority call
(see manual) and then make a call.
The USCG test MMSI # is: 
 
 
 
 
The information that can be passed by a DSC
call on VHF Channel 70 includes the following:
• The caller’s unique MMSI number
• The MMSI number of the unit being called
• The caller’s location and time of location in
a distress by using the distress button when
appropriate
• The requested working frequency and mode
• The priority of call (Distress, Urgent, Safety,
Routine)
• DSC calls can indicate the type of emergency
if selected
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
• DSC calls can be addressed to a certain user,
often referred to as individual calls
• DSC calls can be addressed to a set of users,
often referred to as group calls
• DSC calls can be addressed to a specic
geographic area
• DSC calls can be addressed to all ships and
shore stations, often referred to as Distress
Alerts