The control display unit is one of two ways to control what?

The control display unit serves as a centralized interface for managing multiple aircraft systems, specifically those relating to communication and navigation. It allows operators to control communication radios for voice and data transmission, manage ATC transponders which are critical for air traffic control interactions, facilitate ADF (Automatic Direction Finder) receiver functionality for navigation, and adjust NAV frequencies to ensure the aircraft is using the correct navigational aids.

By having a single unit that integrates control for various systems, it enhances the efficiency and effectiveness of flight management. This centralized control makes it easier for pilots to monitor and interact with essential aircraft systems while flying. Such integration is crucial, especially during complex flight operations where quick adjustments may be necessary.