单选题 Which frequency in the medium frequency band is used for distress and safety traffic by radiotelephony?
相关试题
单选题 What is the primary purpose of the GMDSS?
单选题 The communication system used by the GMDSS includes ______.
单选题 The GMDSS is composed of ______.
单选题 The GMDSS is composed of ______.
单选题 Which statement is false regarding a GMDSS-equipped ship?
单选题 The GMDSS defines four sea areas based on the ______.
单选题 The GMDSSis a world-wide communication network combining ______ with ______.
单选题 GMDSS is the abbreviation of ______.