Re: Speedo question...
OK... I'll bite........ what's this about GPS and radios and DSC (what's DSC anyway?)
It is "Digital Selective Calling"
A marine safety radio system for all mariners
Marine communications changed for ever on February 1, 1999, with the introduction of the Global Maritime Distress and Safety System or GMDSS.
The GMDSS has automated many marine radio functions and processes, particularly those related to distress and safety.
The GMDSS is an amalgam of a number of individual radio systems. Whilst satellite-based systems do play a part in the GMDSS, ?normal? terrestrial radio continues as the primary system for ship-ship and ship-shore communications.
The GMDSS has automated marine radio distress alerting by the use of a technology known as Digital Selective Calling (DSC).
This web site has been established to provide a single point resource on DSC, with a particular focus on VHF DSC and its use by recreational boaters.
We explain how DSC works, what you can use it for, and why you should seriously consider fitting it to your boat and/or limited coast station.
What does VHF DSC do?
DSC is a paging system that uses data signals to automate the transmission and reception of calls on VHF marine radio channel 70.
A DSC message is a brief burst of digitised information transmitted from one station to alert another station or stations. The DSC message automatically indicates the identity of the calling station and the priority/purpose of the call.
Every DSC radio has a unique number, which you use to call other radios, just like a mobile phone. However, unlike mobile phones, DSC allows you to call every other radio in range at the same time if you are in trouble.
Following an alert by DSC message, communications are established between the transmitting station and the receiving station(s) by radiotelephone on a different channel to that used for the DSC call.
DSC is used by ship and coast stations for sending and relaying distress alerts and for other urgency and safety traffic. It can also be used for routine calls.
DSC also offers the ability to send and receive GPS positions - all DSC radios can be connected to a GPS receiver.