In security systems, the term Transmission Line refers to which concept?

• A. A physical barrier
• B. A monitoring station
• C. A signaling path that preserves signal integrity
• D. An alarm sensor

Answer: (C)

Transmission line is the signaling path that carries the alarm signal from a device to the control panel while preserving signal integrity. It involves the physical medium and its electrical characteristics—such as impedance, attenuation, shielding, and proper termination—to prevent noise and reflections and ensure the signal arrives reliably and with correct timing. It’s not a physical barrier, a monitoring station, or the sensor itself—the focus is on how the signal travels and remains intact from device to controller.