🔍 Key Concepts

• MF-HF NBDP (Narrow-Band Direct-Printing) purpose and how it differs from radiotelephone voice tests • Difference between ARQ (Automatic Repeat reQuest) and FEC (Forward Error Correction) modes in NBDP • What is needed to fully confirm both transmitter/antenna and link integrity with a coast station

💭 Think About

• Which choice actually uses the NBDP telex/data function, not just voice communication? • In real GMDSS practice, how do operators confirm that both their NBDP equipment and the coast station circuits are functioning correctly, including answerback codes? • Between ARQ and FEC, which mode provides a positive, automatic confirmation that messages are being received and acknowledged?

✅ Before You Answer

• Verify which options specifically mention NBDP data modes (ARQ/FEC) rather than just voice radiotelephone use • Check which option includes communication with a coast station and an automatic confirmation (e.g., answerback exchange) • Confirm which method would be consistent with GMDSS test procedures for MF/HF NBDP, not just a basic transmitter check