What Does TTY Stand For?by Contributing Writer ; Updated September 28, 2017
A TTY allows deaf and hearing-impaired users to communicate over conventional telephone lines. Users of a TTY device type text into a specialized device, and this text gets to a TTY device on the other end.
What TTY Stands For
TTY stands for "text telephone" or "telephone typewriter."
TTY devices are sometimes called "telecommunications devices for the deaf," or TDDs.
TTY devices require the user on the other end to also have a TTY device, unless a telphone relay service is used.
Telephone Relay Service
Telephone users with hearing must use the relay service if they do not have a TTY device themselves. An operator types the message and sends a text message to the TTY user. The operator speaks the text messages received from the TTY into her phone to allow the person with a standard telephone to hear the message.
TTY Phone Devices
Some TTY devices plug directly into the phone line, or in other instances, the user may have to place the phone receiver on the top of the device.