GX2355S
Owner’s Manual
page 55
9.7
DIGITAL SELECTIVE CALLING (DSC)
Digital Selective Calling is a semi-automated method of establishing a radio call, it
has been designated by the International Maritime Organization (IMO) as an
international standard for establishing VHF, MF and HF radio calls. It has also been
designated part of the Global Maritime Distress and Safety System (GMDSS) and it
is planned that DSC will eventually replace aural watches on distress frequencies
and will be used to announce routine and urgent maritime safety information
broadcasts.
This new service will allow mariners to instantly send a distress call with GPS position
(when connected to the transceiver) to the US Coast Guard and other vessels within
range of the transmission. DSC will also allow mariners to initiate or receive distress,
urgency, safety and routine calls to or from another vessel equipped with a DSC
transceiver.
9.7.1
USCG DSC Watch
The USCG has plans to upgrade its VHF National Distress System (expected by
2005), so at the time of printing only larger vessels that are required to carry VHF
DSC radios will be able to hear your distress transmission
9.8
MARITIME MOBILE SERVICE IDENTITY (MMSI)
9.8.1
What is a MMSI?
A MMSI is a nine digit number used on Marine Transceivers capable of using Digital
Selective Calling (DSC). This number is used like a telephone number to selectively
call other vessels.
9.9
USING DIGITAL SELECTIVE CALLING FEATURES
9.9.1
Distress Call
Transmits a DSC Distress message to all radios equipped to receive a DSC Distress
call. Some Standard Horizon radios may be connected to a GPS to also transmit the
Latitude, Longitude of the vessel.
9.9.2
Individual Call
This feature allows the user to contact another vessel capable of using DSC and
automatically switch the radio to a desired working channel. This feature is similar to
calling a desired vessel on CH16 and requesting them to go to another channel.
