Which component is NOT an input device?

The siren is a component that functions as an output device rather than an input device. Output devices are designed to send information or alerts based on data received from other systems, while input devices gather information from the environment to be processed by a control system.

In the context of security systems, a card reader, glass break detector, and motion detector all serve as input devices. The card reader inputs user access data, the glass break detector senses unauthorized entry through the sound of breaking glass, and the motion detector registers movement within a designated area. Conversely, the siren emits an audible alert when a security breach is detected, thus acting on the information provided by these input devices. This distinction between input and output is crucial in understanding how security systems operate and respond to perceived threats.