What is the main function of a Teletypewriter (TTY)?

The main function of a Teletypewriter (TTY) is to send and receive typed messages over telephone lines. TTY devices are specifically designed to convert typed characters into electrical signals that can be transmitted over standard phone lines. This capability allows individuals, particularly those who are deaf or hard of hearing, to communicate effectively by typing messages to each other in real-time. When one person types a message on a TTY, it is sent through the telephone line and printed on the receiving end, allowing for instant communication.

The other options do not accurately describe the primary function of a TTY. Creating multimedia presentations involves various digital tools and formats unrelated to traditional text transmission. Video conferencing utilizes audio and visual technology rather than typed text communication. Enhancing sound quality pertains to audio communication methods rather than the text-based capabilities of a TTY device.