A coded supervisory signal must consist of not less than how many rounds of the transmitted number to indicate fault, and how many rounds to notify restoration to normal?

A coded supervisory signal must consist of not less than how many rounds of the transmitted number to indicate fault, and how many rounds to notify restoration to normal?

• A. 2 rounds for fault and 1 round for restoration
• B. 3 rounds for fault and 2 rounds for restoration
• C. 1 round for fault and 2 rounds for restoration
• D. 2 rounds for fault and 2 rounds for restoration

Answer: (A)

In a coded supervisory signal, the number of repetitions of the same transmitted number shows the state of the monitored condition. A fault is indicated by sending the code in two or more rounds, which helps confirm the condition isn’t just a brief glitch. When the condition returns to normal, the system sends the same code only once, signaling restoration to normal. So the standard is two rounds for fault and one round for restoration. Using three rounds for fault isn’t required and wastes signaling time, while one round for fault wouldn’t reliably indicate a fault. Two rounds for restoration would blur the distinction between a fault and its recovery, and keeping it to a single round keeps the meaning clear.

In a coded supervisory signal, the number of repetitions of the same transmitted number shows the state of the monitored condition. A fault is indicated by sending the code in two or more rounds, which helps confirm the condition isn’t just a brief glitch. When the condition returns to normal, the system sends the same code only once, signaling restoration to normal. So the standard is two rounds for fault and one round for restoration. Using three rounds for fault isn’t required and wastes signaling time, while one round for fault wouldn’t reliably indicate a fault. Two rounds for restoration would blur the distinction between a fault and its recovery, and keeping it to a single round keeps the meaning clear.