Which statement about the end-of-line resistor in a protected circuit is most accurate?

Which statement about the end-of-line resistor in a protected circuit is most accurate?

• A. It monitors the continuity and health of the circuit
• B. It powers the circuit during outages
• C. It acts as a signal amplifier
• D. It is used to indicate door status

Answer: (A)

The end-of-line resistor is used to supervise the protected circuit by creating a defined reference resistance at the far end of the loop. The panel continuously monitors this resistance to confirm the circuit remains intact. If the wiring is opened, shorted, or a device near the end fails, the resistance changes outside the expected range and the panel triggers a fault or alarm. It does not serve as a power source during outages, nor does it amplify the signal, and it isn’t used to indicate door status. Door status is determined by the door contact devices and the panel’s input logic, not by the end-of-line resistor.

The end-of-line resistor is used to supervise the protected circuit by creating a defined reference resistance at the far end of the loop. The panel continuously monitors this resistance to confirm the circuit remains intact. If the wiring is opened, shorted, or a device near the end fails, the resistance changes outside the expected range and the panel triggers a fault or alarm. It does not serve as a power source during outages, nor does it amplify the signal, and it isn’t used to indicate door status. Door status is determined by the door contact devices and the panel’s input logic, not by the end-of-line resistor.