Digital Selective Calling
Digital Selective Calling
NOTE: Before you can use DSC capabilities, you must enter a Mobile Marine Safety Identity (MMSI) number
(
Entering Your MMSI Number, page 10
). An MMSI number identifies each DSC radio, like a telephone number.
Digital Selective Calling (DSC) is a key component of the Global Maritime Distress and Safety System (GMDSS).
DSC enables VHF radios 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, longitude, and the current time are
transmitted when you send a distress call or other type of DSC call. If you enter your position information
manually, your latitude, longitude, and time of entry are transmitted with the call. Transmitting your location
automatically speeds help in an emergency situation.
Channel 70 is reserved exclusively for DSC calls, and your device 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. Your device
changes to Channel 70 automatically to transmit a DSC call. Your radio sends the DSC data over Channel 70 in
less than one second, and then tunes to an appropriate channel for voice communications.
appears on the device screen when you have an incoming or missed DSC call.
NOTE: The device disables DSC automatically when you turn on ATIS (
Automatic Transmitter Identification
).
Entering Your MMSI Number
NOTICE
You can enter your MMSI number only once. If you must change your MMSI number after entering it, you must
take your radio to your Garmin
®
dealer for reprogramming.
The Mobile Marine Safety Identity (MMSI) number is a nine-digit code that acts as a DSC self-identification
number, and it is required 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 these sources:
• Federal Communications Commission (FCC): assignments are recognized internationally
• BoatU.S.
®
, Sea Tow
®
, or United States Power Squadrons
®
: assignments are for USA waters only.
1 Select MENU > DSC > MY MMSI.
2 Enter your MMSI number (
).
3 Select ACCEPT.
The radio prompts you to confirm your identity.
4 Enter your MMSI number again, and select ACCEPT.
If the MMSI numbers you entered do not match, a message appears.
5 If necessary, select RETRY, and enter the number again.
Viewing Your MMSI Number
Select MENU > DSC > MY MMSI.
Distress Calls
When you make a distress call, your call is transmitted to all DSC-capable radios within receiving range. Your
current GPS position (latitude and longitude) and the current time are included in the transmission if you have a
GPS device connected to your transceiver. If you manually entered your position information with the time, that
data is transmitted with the call.
NOTE: You should familiarize yourself with the standard distress-call format and protocol to ensure your calls
are clear and effective.
10
Digital Selective Calling
