Chapter 5: Digital Selective Calling (DSC) 31
Chapter 5: Digital Selective Calling (DSC)
The Ray54 includes equipment for Class “D” Digital Selective Calling
(DSC). DSC protocol is a globally applied system used to send and receive
digital calls. DSC uses a unique Maritime Mobile Service Identity (MMSI)
number to direct DSC calls directly to your radio, much like a telephone
number. When the DSC signal is received, the radio quickly switches over to
channel 70 and performs the corresponding operation.
Note: An MMSI number is required to operate the DSC equipment in this ra-
dio. You can obtain an MMSI from BoatUS (www.boatus.com). Once ob-
tained, you can program the MMSI number yourself one time only using the
operation described in My MMSI ID on page 72. Otherwise, your Rayma-
rine dealer can program or change the number for you.
The Ray54 includes a separate dedicated receiver just for DSC
communications on channel 70. When a DSC call is received, the Ray54
automatically responds based on the type of call. When receiving a DSC call
from another vessel or a coast station, an alert sounds and DSC data appears
in the LCD–such as time of a call, the caller and the type and priority of a call.
The Ray54 can make the following type of DSC calls:
• INDIVIDUAL (routine) Calls are made to a specific station identified by
its MMSI number. See page 34.
• GROUP (routine) Calls send transmissions that are only received by
radios that share a common Group MMSI number. See page 38.
• ALL SHIPS Calls send out a message to all vessels within range. See
page 42. The Ray54 can make two different types of All Ships calls:
1. SAFETY Calls for advisory alerts
—or—
2. URGENCY when the assistance is required but the situation is not
serious enough for a Distress Call
• DISTRESS Calls send your vessel’s position and time information to
other ships and shore stations, along with (optionally) the nature of your
Distress situation. See page 45.
• POSITION REQUEST calls enable you to request GPS position infor-
mation from any station for which an MMSI number is known. You can
also send out your position to others.
