In a fire alarm system using signaling line circuits, the fire alarm control panel may which of the following to determine device status?

In a fire alarm system using signaling line circuits, the fire alarm control panel may which of the following to determine device status?

• A. Periodically poll each device to determine its status
• B. Receive regular updates from each device about its status
• C. Both A and B
• D. Neither

Answer: (A)

In signaling line circuits, the fire alarm control panel determines each device’s status by interrogating the devices on the loop. The panel periodically sends a poll to every device, and each device responds with its current state (normal, alarm, trouble, supervisory) and any relevant data. This polling approach gives the panel a reliable, up-to-date snapshot of the entire circuit and keeps communication orderly on the two-wire loop. Status updates aren’t spontaneously pushed by devices on SLCs; they reply only when asked. So while there is two-way communication, the flow is initiated by the panel’s polls, not by devices sending regular unsolicited updates. That’s why the best choice is that the panel polls each device to determine its status. The option implying devices regularly push updates would not reflect how signaling line circuits are designed to operate.

In signaling line circuits, the fire alarm control panel determines each device’s status by interrogating the devices on the loop. The panel periodically sends a poll to every device, and each device responds with its current state (normal, alarm, trouble, supervisory) and any relevant data. This polling approach gives the panel a reliable, up-to-date snapshot of the entire circuit and keeps communication orderly on the two-wire loop.

Status updates aren’t spontaneously pushed by devices on SLCs; they reply only when asked. So while there is two-way communication, the flow is initiated by the panel’s polls, not by devices sending regular unsolicited updates. That’s why the best choice is that the panel polls each device to determine its status. The option implying devices regularly push updates would not reflect how signaling line circuits are designed to operate.