How does Air Traffic Control (ATC) communicate with vital services?

Air Traffic Control (ATC) primarily uses radio communication as the standard method for relaying instructions and information to pilots and other aircraft. This is an essential part of ensuring safety and efficiency in air traffic management. Radio communication allows for real-time, clear verbal exchanges that can be swiftly enacted, which is vital for maintaining safety in busy airspace.

The other methods mentioned have limited use in the context of ATC communication. Visual signals might be employed in specific situations or by ground services but are not the primary means of communication between ATC and aircraft. Cellular phones are not typically used for ATC communications due to concerns over reliability and the need for immediate, uninterrupted communication in dynamic air traffic scenarios. Thus, radio communication remains the most effective and reliable means of connecting ATC with vital air traffic services.