FCC Exam Question: 21B2
The sequence ARQ, FEC, SFEC best corresponds to which of the following sequences?
Explanation: ARQ (Automatic Repeat reQuest) systems require a return channel for the receiving station to acknowledge reception or request retransmission of corrupted data. This inherent interactivity makes ARQ a **two-way communication** method. FEC (Forward Error Correction) involves adding redundant data to a transmission, allowing the receiver to detect and correct errors without needing to request retransmissions from the sender. As no return path is required, FEC is efficient for **one-way communications to all stations** (broadcasts). SFEC (Selective Forward Error Correction) is a more specialized form of FEC where the error correction might be applied selectively or targeted to a specific receiver or a small, defined group, rather than a universal broadcast. While still a one-way method, its "selective" nature distinguishes it, aligning with **one-way communications to a single station**. Therefore, the sequence ARQ, FEC, SFEC corresponds to Two-way communications, one-way communications to all stations, one-way communications to a single, making option B correct. Options A, C, and D are incorrect because they misalign the fundamental nature (two-way vs. one-way) or the scope (all stations vs. single station) for one or more of the protocols.
11B4
46F6
35D5
33D6
19B2
Pass Your FCC Exam!
Study offline, track your progress, and simulate real exams with the GMDSS Trainer app.
Includes Elements 1, 3, 6, 7R, 8, and 9.