🔍 Key Concepts

• SITOR modes: ARQ vs FEC and which one is used for one-way broadcasts like weather and safety information • How error correction is achieved in ARQ compared to FEC (who talks to whom, and how many times characters are sent) • Whether two‑way contact with a coast station is required just to receive certain types of broadcasts

💭 Think About

• For ARQ, ask yourself: does the receiving station have to send acknowledgments back, and how does that affect how many times each character is sent? • For FEC, think about: is it designed mainly for one-way broadcasts or two-way traffic, and does the receiver need to establish a link before copying the traffic? • For weather or MSI (Maritime Safety Information) broadcasts, would it be practical to require every ship to set up a two-way circuit, or is there a simpler way?

✅ Before You Answer

• Verify which mode (ARQ or FEC) actually sends each character twice for redundancy. • Confirm whether FEC broadcasts (like weather or safety messages) require any kind of two-way handshake or answerback before you can receive them. • Check which statement, if any, confuses the roles of ARQ and FEC in terms of two-way vs one-way operation.