DSC Diagrams
DSC Calls
Make digital calls so more people hear you.
World Wide Group Numbers by Country
This system was developed by several cruiser around the world and later sanctioned by at least the US GMDSS task force as a good way for cruisers to contact each other when they do not know other boat names.
Programming your area's group number in your HF and VHF radios is all you have to do. When you make a call to that group, all radios with that number are called within your transmission area.