Which type of condition is indicated within 200 seconds as part of signaling line circuit integrity monitoring?

Which type of condition is indicated within 200 seconds as part of signaling line circuit integrity monitoring?

• A. Short
• B. Supervisory
• C. Close
• D. Open

Answer: (D)

In signaling line circuit integrity monitoring, the system constantly checks that the two-wire line remains continuous and responsive. If the circuit is interrupted—such as a wire break or a disconnected device—the line becomes open. The monitor uses a timer, and if no valid response is received within about 200 seconds, it flags an open condition. This is why the indicated condition within 200 seconds is Open: the open state reflects a loss of continuity on the signaling line, which is what the integrity monitor is designed to detect over that time window. Short would indicate a different fault (a low-impedance fault on the line) and is detected by different criteria, while Close is not a standard signaling line fault state.

In signaling line circuit integrity monitoring, the system constantly checks that the two-wire line remains continuous and responsive. If the circuit is interrupted—such as a wire break or a disconnected device—the line becomes open. The monitor uses a timer, and if no valid response is received within about 200 seconds, it flags an open condition. This is why the indicated condition within 200 seconds is Open: the open state reflects a loss of continuity on the signaling line, which is what the integrity monitor is designed to detect over that time window. Short would indicate a different fault (a low-impedance fault on the line) and is detected by different criteria, while Close is not a standard signaling line fault state.