TTY
(TDD)
Text Telephone / Teletype Terminal / TeleTYpewriter
Telecommunication Device for the Deaf
A TTY is a special device that lets people who are deaf, hard of hearing, or speech-impaired use the telephone to communicate, by allowing them to type text messages. A TTY is required at both ends of the conversation in order to communicate.
It can be used with both land lines and cell phones. Unlike text messaging, it is designed for synchronous conversation, like a text version of a phone call.
A modern digital cell phone must support a special digital TTY mode in order to be compatible with a TTY device.
See: Digital TTY/TDD
TDD can also stand for Time Division Duplex, a method for general two-way radio communication, unrelated to hearing-impaired applications.
See: TDD
Last updated Dec 16, 2019 by Rich Brome
Editor in Chief Rich became fascinated with cell phones in 1999, creating mobile web sites for phones with tiny black-and-white displays and obsessing over new phone models. Realizing a need for better info about phones, he started Phone Scoop in 2001, and has been helming the site ever since. Rich has spent two decades researching and covering every detail of the phone industry, traveling the world to tour factories, interview CEOs, and get every last spec and photo Phone Scoop readers have come to expect. As an industry veteran, Rich is a respected voice on phone technology of the past, present, and future.
