What is a characteristic of a Proprietary fire alarm system?

A proprietary fire alarm system is specifically characterized by being maintained by a single organization or company. This means that the system's design, installation, and maintenance are generally managed by that one entity, ensuring that it adheres to particular standards and protocols set by the manufacturer or provider. This approach offers advantages such as uniformity in system components and specialized support, which can lead to improved reliability and efficient operation.

In contrast, other options do not correctly describe proprietary systems. For example, the characteristic of being connected to all municipal systems does not inherently define a proprietary system, as these systems can function independently of municipal connections. The assertion that they are only used in residential buildings is overly restrictive, as proprietary systems can also be installed in commercial environments. Lastly, while proprietary systems may connect to communication networks, they are not defined by their ability to connect to multiple networks; rather, they are defined by the singular management and ownership aspect.