Which of the following best defines a fire alarm system component that has discrete identification?

A fire alarm system component that has discrete identification is best defined as an addressable device. An addressable device is assigned a specific address within the fire alarm system, which allows for precise communication and identification. This means that each device can be uniquely identified by the control panel, enabling it to report its status and any alarms it may detect.

The main advantage of addressable devices is that they provide the ability to pinpoint the exact location of an issue within the system, which is crucial for rapid response during a fire event. This capability enhances the system's overall effectiveness, as it allows for quicker troubleshooting and maintenance.

In contrast, other components such as channels, detectors, and control units do not have the same level of discrete identification. While detectors can include both addressable and conventional variants, the term "detector" on its own does not specify that it has a unique address. A control unit manages the overall fire alarm system but is not itself identified as a discrete device like an addressable device is. Channels typically refer to pathways for communication within the system rather than individual components with unique addresses. Thus, addressable devices stand out for their discrete identification feature in fire alarm systems.