When you call another DSC set using the MMSI number, you set the desired working channel before you transmit the call, usually 6,8,72 or 77. When the called person presses the acknowledge button on their set, both sets switch to that working channel automatically, you can be overheard by anyone listening to that working channel. It is only the initial call which is specific to the MMSI.aquaplane wrote:Don't get me wrong, I'm proud to be a Luddite.
Sometimes I can see the advantage in addopting these new fangled ideas though.
DaveS, with an MMSI number you can call someone on VHF and the message only goes to them from you. When they answer you can chat without anyone else listening in. The set will even beep to tell you there is a message for you much like a moby phone call.
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You can also request a position from another DSC equipped vessel automatically if you know the MMSI, if you have your sets set to auto acknowledge, you can easily keep track of any vessel you are sailing in company without any voice coms.
To use all the functions available easily, a set with a key pad is much easier than those without. Some sets I have come across are not intuitive and have the menus hidden away in the most obscure fashion.
It is worth noting that since the advent of DSC most big ships no longer listen on 16, they do however listen for other ships on 13 which is for bridge to bridge coms. If you are calling a ship on 16 who doesn't respond, try 13.