Originally Posted by Freesail99
All dsc radios have a number, a phone number if you will. That number can be generated by the dsc radio and used to call or set off an alarm in the ship. Changes are, there would not be many ships in the same area. I did not say a all ships call. You may find the dsc to be a much better tool at sea then a radar reflector. Also, the radios dsc number could also be used to "call or ring" a friends boat.
Ok - so this ship is coming at you at night, so its difficult to read his name and even if you can, do you know his MMSI? You try him on channel 16, no answer, then on channel 13, no answer, etc.. Or you can hit the all-ships call, maybe that will wake him up.
Now add AIS, and the picture looks a lot better, because the AIS should give you his MMSI.