Digital selective calling (dsc) – Garmin GPSMAP 376C User Manual

Page 135

Digital Selective Calling (DSC)

DSC uses marine VHF radio GPS technologies to transmit and

receive location information. DSC is used by mariners to assist them

in two major areas: Distress Calls and Position Reporting.
A non-emergency DSC Position Report allows mariners to exchange

and show their positions. When you receive a DSC position, you can

create a waypoint or to show the received position on an electronic

map.
An emergency DSC Distress Call allows a vessel in trouble

to transmit a substantial amount of information in a single

transmission, or “call,” without the need for voice communication.

When any nearby rescuer receives the DSC signal, an alarm sounds,

and they immediately receive the position of the caller.
The rescuer can then navigate (Go To) the caller’s position to

assist or forward the call on to the Coast Guard. When the Coast

Guard receives the call, they can immediately access the caller’s

information in their database while in transit to the caller’s location.
Any time a vessel receives a DSC call, the vessel can store that

location and quickly navigate to that position using a Go To. This

makes DSC a time-saver, especially in an emergency situation. To

use DSC, users must first register their VHF radio with the FCC and

receive a Maritime Mobile Service Identity (MMSI) number.

What is a Maritime Mobile Service Identity (MMSI)

Number?

MMSI allows a VHF radio to act like a phone. The 9-digit MMSI

number acts like a phone number when used in a position report and

as a unique identifier to the Coast Guard when used in an emergency

distress call. To obtain a MMSI number, users must register their

VHF radio with the FCC (Form 605). Garmin does not supply this

number.
For more information regarding MMSI numbers, visit

How Are MMSI Assignments Obtained?

Non-commercial users, such as recreational users, who remain

in United States waters and only carry VHF, EPIRB (Emergency

Position Indicating Radio Beacons), and Radar are not required to

have a FCC ship station license. The FCC and Coast Guard have

authorized some second and third-party vendors to assign MMSI

numbers. This service is limited to registering recreational vessels

only. To receive information on how to obtain a recreational MMSI

GPSMAP 376C Owner’s Manual

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