The Marine Radiotelephone Service or HF ship-to-shore operates on shortwave radio frequencies, using single-sideband modulation. The usual method is that a ship calls a shore station, and the shore station's marine operator connects the caller to the public switched telephone network. This service is retained for safety reasons, but in practice has been made obsolete by satellite telephones, particularly INMARSAT.
See more at Wikipedia.org...
Free Download Now!
