Homonym: TTY (Text)
TTY, or Text Telephone, is a device that allows individuals who are deaf, hard of hearing, or have speech disabilities to communicate over the phone using text. Users type their messages on a keyboard, and the text is transmitted over the phone line to another TTY user or a relay service operator, who reads the message aloud to the hearing person on the other end.
TTY devices typically have a small screen to display the text and a keyboard for typing. They can connect to standard phone lines and are often used in conjunction with relay services, which help facilitate communication between TTY users and those who do not have TTY devices.