🔍 Key Concepts

• Role of ARQ (Automatic Repeat reQuest) mode in SITOR/NBDP communications • Meaning of "Automatic Exchange of Answerbacks" between a ship station and a coast station • Normal sequence of actions for a GMDSS operator when establishing and setting up an NBDP link

💭 Think About

• In ARQ mode, what is handled automatically by the equipment, and what requires manual input from the operator? • What is the purpose of exchanging answerbacks at the beginning of a SITOR NBDP call with a coast station? • At what point in the link setup does the operator actually choose or send a message or command?

✅ Before You Answer

• Verify what the answerback actually is (ID of the station vs. content of the message**)** • Check whether the operator must manually trigger any answerback during ARQ or if the system handles it after link establishment • Confirm when the system or coast station prompts the operator for commands or message sending in the normal call sequence