______ belong(s) to the land or terrestrial systems.

Traditional terrestrial techniques work on ______.

Sea area A2 is an area, excluding sea area A1, within the coverage of at least one ______.

Which equipment is required to be carried in all sea areas? ①VHF equipment; ②SART; ③SES; ④MF/HF equipment; ⑤EPIRB

Terrestrial traffic system has the following equipment ______。

What shall be transmitted to avoid all ships in a large sea area being alerted?

INMARSAT priority levels have ______.

The ARQ mode should be applied ______.

The FEC mode is used for ______ from ______ station to two or more other stations when available.

Which transmissions are permitted on the frequency 2,174.5 kHz in NBDP service?

Which one of the following keystrokes or characters is sent as part of ARQ communications to switch information transmission control from one station to the other?

In which mode should urgency communication "to all stations" by direct printing telegraphy normally be established?

At mid-day, what would be the best choice in attempting to communicate, using NBDP with a shore station some 800 nm (1,482 km) distant?

Which of the following description of usage is suitable for 2,174.5 kHz frequency?

The conversation mode between two stations in NBDP service is ______.