VHF 300 Series Owner’s Manual
Digital Selective Calling
Digital Selective Calling
Digital Selective Calling (DSC) is a key component of the Global Maritime Distress and
Safety System (GMDSS). DSC provides VHF radios with the ability to place and receive
digital calls directly with other vessels and shore stations, including the USA and Canadian
Coast Guards. Your radio includes full Class D DSC capabilities.
If you have a GPS device connected to the transceiver, your latitude and longitude and the
current time are transmitted when you send a distress call or other type of DSC call. If you
have manually entered your position information, your latitude, longitude, and time of entry
are transmitted with the call. Having your location automatically transmitted prevents you
from needing to identify your location in an emergency situation.
Channel 70 is reserved exclusively for DSC calls, and your radio uses a dedicated receiver
to maintain a constant watch on Channel 70. You do not need to change the channel to make
a DSC call, since your radio automatically changes to Channel 70 to transmit a DSC call.
Your radio sends the DSC data over Channel 70 in less than one second, and then tunes to
the appropriate channel for voice communications. The icon is displayed when you
have an incoming or missed DSC call.
IMPORTANT:
To use the DSC capabilities of your radio, you must first enter a Mobile
Maritime Safety Identity (MMSI) number. An MMSI number identifies each DSC radio,
like a telephone number.
IMPORTANT:
The radio disables DSC if you turn on ATIS. See
Entering Your MMSI Number
The Mobile Maritime Safety Identity (MMSI) number is a nine-digit code that acts as a
DSC self-identification number, and is required in order to use the DSC capabilities of your
radio. You can obtain an MMSI number from the telecommunications authority or ship
registry for your country. In the USA, you can obtain an MMSI number from the following
sources:
Federal Communications Commission (FCC)—assignments are recognized
internationally
BoatU.S., Sea Tow, or United States Power Squadrons
®
—assignments are for USA
waters only
After obtaining your MMSI number, you must program the number into your radio to
enable DSC.
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