A.receiving messages/one station B.transmission/ one coast station or ship C.communicating /one ship D.contacting/other
A.120/20 B.56/18 C.100/16 D.96/8
A.VHF channel16 and 13 B.appropriate DSC distress and safety frequency C.INMARSAT TDM message channel D.VHF channel 70 and channel 8