VHF 300 Series Owner’s Manual 15
Digital Selective Calling
IMPORTANT: Use caution when entering your MMSI number, because you can only enter
it once. If you need to change your MMSI number after entering it, you must take the radio
to your Garmin dealer for reprogramming.
To enter your MMSI number:
1. Press the MENU key.
2. Select DSC > MY MMSI.
3. For each number in the sequence, turn the Channel knob clockwise to increase the
number, and counterclockwise to decrease the number. Press the Channel knob to
move to the next number in the sequence. Select ab to return to a previous character.
4. Select ACCEPT when you have entered your MMSI number. The radio prompts you
conrm your entry.
5. Enter your MMSI number again, and select ACCEPT. If the MMSI numbers you entered
do not match, the screen displays “MMSI NUMBERS DO NOT MATCH”. Select RETRY
and repeat the process. If you do not want to enter your MMSI number at this time,
select CANCEL.
Viewing Your MMSI Number
1. Press the MENU key.
2. Select DSC > MY MMSI.
3. Select OK to return to the previous screen, or press the MENU key to return to the Home
screen.
DSC Distress Calls
When you make a DSC 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 have manually entered your position information with the time, that
data is transmitted with the call. For information on manually updating your position
information, see page 26.
NOTE: Familiarize yourself with the standard distress-call format and protocol to ensure
that your calls are clear and effective.

Sending an Undesignated Distress Call

When you send an undesignated distress call, the nature of your emergency is not
transmitted to the receiving stations. Sending an undesignated distress call is a shorter and
quicker procedure that can save you time during an emergency.
1. Lift the spring-loaded door, and press and hold the DISTRESS key for at least three
seconds. The transceiver beeps, and the screen displays “DISTRESS CALL COUNTING
DOWN”. The channel pane counts down the seconds from 3 to 1.