On-screen radios work just like the radio stack in your aircraft:

Record and playback your own radio calls with interactive audio exercises. Operate the on-screen radios (Comm 1, Comm 2, Nav 1, Nav 2, and audio panel) - Comm1 VFR radios tune and respond just like the real thing! Simulate emergency radio procedures. Access the most widely used aviation resources for frequencies and communication information using a standard airport directory and aeronautical charts.