Answer:
(1) Digital Selective calling
(2) Mayday
(3) Emergency
(4) GPS
(5) Position
(6) MMSI (Maritime Mobile Service Identity)
Step-by-step explanation:
VHF stands for "Very High Frequency". VHF radio is a vital means of communication for ships and provides many benefits.
VHF radio also has a feature of digital selective calling (DSC) where a simple one-button distress call can be sent in case of any emergency just like mayday call is used in airplanes.
Moreover, if the VHF radio is interfaced with the GPS of the vessel then the distress call will automatically send the current position of the vessel.
Just like you have to buy a sim card for mobile communication, in the same way, you are required to get an MMSI (Maritime Mobile Service Identity) number to properly use DSC radio.