How to Configure the VATSIM's Voice
Go into the FSFDT Control Panel. It's the two rows of three lights in the task tray. Expand the Voice Menu. Select VATSIM. Ensure there is a check mark in Enable VATSIM Voice on this computer.
Set your Microphone, Headset, and Speakers, according to your preferred sound device.
Under Key mappings, set your PTT (Push To Talk) keys and joystick buttons.