In a supervised circuit, which device terminates the circuit?

In a supervised circuit, which device terminates the circuit?

• A. Junction box
• B. Inline repeater
• C. End of line device
• D. Power supply

Answer: (C)

In supervised circuits, the circuit is terminated by the end-of-line device so the panel has a defined impedance to continuously monitor. This device provides a known resistance at the far end of the loop, allowing the fire alarm control panel to detect opens, shorts, or tampering. When the circuit is intact, the panel reads the expected value; if the line is broken or shorted, the impedance changes and a fault or alarm is generated, ensuring reliable supervision. A junction box is just a wiring connection point, not a termination that supports supervision. An inline repeater extends or conditions the signal, not terminate the circuit for supervision. A power supply only provides power to devices on the loop and does not serve as the terminating supervision element.

In supervised circuits, the circuit is terminated by the end-of-line device so the panel has a defined impedance to continuously monitor. This device provides a known resistance at the far end of the loop, allowing the fire alarm control panel to detect opens, shorts, or tampering. When the circuit is intact, the panel reads the expected value; if the line is broken or shorted, the impedance changes and a fault or alarm is generated, ensuring reliable supervision. A junction box is just a wiring connection point, not a termination that supports supervision. An inline repeater extends or conditions the signal, not terminate the circuit for supervision. A power supply only provides power to devices on the loop and does not serve as the terminating supervision element.