Several types of calls can be made from most DSC radios:
Individual — Once you know the MMSI number of a buddy’s boat, you would enter it into your radio’s Individual Directory, along with their boat or buddy’s name. To make a DSC call, select Individual, select the entry you want to call. On most radios, you will be prompted to select a working channel number, then you must acknowledge that you want to make the call. Your buddies DSC radio will then ring, showing you as the caller and the channel number both radios will be switched to. Some radios require an acknowledgement or two, then both radios will be on the same channel and you would use the radio as usual.
Group — Once you know the Group number of the organization you want to call, you would enter it in the Group Directory. Making a call is basically the same as above, except you would use the Group Directory. All radios that are turned on, are in range and have that Group number entered would hear bells indicating they are invited to join a Group call. Most radios require an acknowledgement, then will be switched to the working channel. The next step is a little controversial as all radio operators are listening and someone should start the conversation. The recommendation is the operator that initiated the call should announce something like “this is vessel (MyBoat) to any boat that got dragged to channel xx, please come in”. The assumption is the operator initiating the call is a bit more knowledgeable with Group calls, so should make the first step. If anyone reading this has a different opinion, please send an email to firstname.lastname@example.org with your opinion.
All Ships — This basically performs the function as a distress call, but is used if a vessel is NOT in distress. The radio asks for the category of call (safety–similar to SECURITY, urgency–similar to PAN PAN) and asks for the working channel.
Position Request — You would use this type of call if you want to get another vessel’s GPS coordinates. This feature uses entries in your Individual Directory. If your radio is properly connected to a chart plotter, that plotter and your radio supports sending/receiving this information, a window should appear on your plotter with the coordinates.
Position Report — You would use this type of call if you want to send your GPS coordinates to another vessel. This feature uses entries in your Individual Directory.
Polling (may be called Auto Polling — You would use this type of call if you want to know if a (or more than one) specific vessel is in range. If you get an acknowledgement, you will get its coordinates and these may be displayed on a chart plotter.
DSC Test — You may test your radio and if in range get an acknowledgement from the Coast Guard or another vessel. Everyone should put the Test MMSI number in their Individual Directory. For the USA, the Coast Guard’s Test station’s MMSI is 003669999. If you are in range, you would get an acknowledgement from the radio similar to RX DSC TEST. If you are out of range to the Coast Guard, you can test through another DSC radio. In the Individual Directory, select the MMSI number of the radio in range, and if all is working properly, you should get RX DSC TEST on your radio.