You can find installation and user instructions on mode webpage. Documentation for modders and scripters is available here.

TFAR gives your a way to communicate using your direct voice or 13 different radios (including rifleman, personal, longange, airborne and underwater radios).

Every 5 seconds someone in the world starts TFAR.

Some features:

• Radio and direct speech (3D)
• Voice volume
• 3 rifleman, 3 personal, 3 manpacks, 3 airborne radios
• Multiband radios
• Full Zeus support
• Speakers on radios
• Manpack models
• Day and night interfaces
• Underwater speech and radio communications
• Signal interference depending on distance and ground surface
• Vehicles sound occlusion
• Radio volume
• Spectator mode
• PvP and PvE modes
• Ability to pick up radios from killed enemies
• Encryption codes for radios
• Stereo channels for radio
• API
• etc...

BIS thread.