Identify one key component of a One-Way Voice Communication System.

One of the key components of a One-Way Voice Communication System is the speakers installed throughout the building. These speakers play a crucial role in the system as they are responsible for disseminating emergency announcements and instructions from the control panel to occupants in various areas of the building. This allows for efficient communication during emergencies, ensuring that everyone receives timely and clear information to promote safety and facilitate an organized response.

The other options, while they may be part of a broader safety and security system in a building, do not constitute the primary mechanism for one-way voice communication. The main control panel serves as the command center for operating the system, but it does not directly communicate with occupants. Door alarms and smoke detectors assist in alerting to security breaches or fire conditions, respectively, but neither serves the function of delivering voice communications to individuals in the way that speakers do.