International Navtex service means the coordinated broadcast and automatic reception on（）khz of maritime safety information by narrow-band direct-printing telegraphy using English language.

What following is not among the function of SOLAS ships?（）

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.

（）will form the basis for distress alerting and safety calling.

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

The frequency（）the safety message will be transmitted shall be included in DSC safety call.

Radio communication（）for many years and helps to save tens of thousands of lives.

On-scene communications will normally take place between（）.

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

The vessel has stayed in port for seven days because she needs（）.