By using（）system a ship can send a distress message and know with certainty it will be received.

Stations in the United States of America are grouped by states arranged in the alphabetical order of their（）.

Every lifeboat which is fitted with a fixed two-way（）radiotelephone apparatus with an antenna which is separately mounted shall be provided with arrangements for sitting and securing the antenna effectively in its operating position.

Before GMDSS, if the radio officer on board is serious ill,（）.

Distress traffic is the communication（）between the station in distress and the ships, aircraft, coast radio stations, coast earth stations and rescue centers participating in the rescue work.