Which radio layout is characterized by each agency operating on their own designated frequency?

The correct answer is characterized by each agency operating on their own designated frequency. In a conventional radio layout, communication is conducted on specific frequencies assigned to different agencies or departments. This means that each agency has a distinct channel that is used for all their communications, allowing for clear and organized conversation without interference from other agencies.

This setup is particularly beneficial in emergency situations where clarity and reliability of communication are paramount. Conventional systems may resemble older analog systems but have been widely used due to their straightforward operation and compatibility with a large number of different radio devices.

In contrast, other options like simulcast radio, trunked radio, and integrated radio involve more complex systems where frequencies are shared or dynamically allocated among multiple users or agencies. For instance, trunked radio allows multiple users to share a set of frequencies, automatically assigning channels as needed, which might not suit environments where separate, reliable lines of communication are required.