🔍 Key Concepts

• Inmarsat Fleet 77 system components – what roles do RX2 and the Antenna Control Unit (ACU) play? • How system faults are indicated – typical wording used on GMDSS/Inmarsat terminals for hardware communication failures vs. normal operation indications. • Difference between signal/lock indications and error/fault messages on satellite terminals.

💭 Think About

• Which of these options clearly describes a fault condition between two pieces of equipment, rather than normal successful operation? • Look at each choice and ask: does this describe something working correctly (receiving/locking onto a channel) or something going wrong (a communication failure)? • For Inmarsat/GMDSS equipment, what type of on‑screen message would you expect when there is a problem with internal communication between units such as a receiver and ACU?

✅ Before You Answer

• Identify which options describe normal reception/lock on the NCSC (Network Co‑ordination Station Channel) – those are less likely to be a failure indication. • Check which option explicitly mentions a communication error between RX2 and the ACU (look for the word "Comm" or "error" in the wording). • Verify that configuration problems between DCE/DTE (data circuit‑terminating equipment / data terminal equipment) are a different interface than the internal link between RX2 and the ACU.