Dsc Procedures; Introduction To Dsc - Simrad RS90 Operating Manual

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DSC Procedures

Introduction to DSC

DSC (Digital Selective Calling) is part of the Global Maritime Distress
and Safety System. It allows radio stations to contact each other on
a dedicated digital channel (channel 70). The radios automatically
exchange the digital contact and acknowledgement messages
on channel 70, freeing up the other VHF channels for voice
communications.
Once they have established contact, both radios automatically
switch to a VHF working channel for the operators to carry out
normal voice communication.
Each DSC radio has a unique 9-digit number, known as a Maritime
Mobile Service Identity (MMSI), which is used to contact that
individual radio.
DSC radios continuously monitor channel 70 irrespective of what
other channels they are working on. If someone calls your vessel via
DSC, your radio will sound an alert tone for you to respond to the
call.
If the RS90 radio is connected to a GPS system, it will automatically
send your location when calling other stations. This is especially
useful for distress calls.
DSC process
The calling and acknowledging process on channel 70 operates as
follows:
1.
The calling radio transmits a DSC signal on channel 70.
2.
Receiving radio(s) sound alert tones for their operators.
3.
For individual, LL request and DSC test calls, the receiving radio
sends a DSC acknowledge signal on channel 70.
4.
Both the calling and receiving radios switch to a working VHF
channel (except for LL request and DSC test calls).
5.
Calling and receiving operators commence normal VHF voice
communications on the working channel.
6.
Press [X] to return to standby mode.
DSC Procedures | RS90 Operating Manual
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