Telecommunications Display Device (TDD)

A Telecommunications Display Device (TDD), also known as a text telephone, is a telephone equipped with a keyboard and a display for people who are hearing- or speech-impaired. A TDD allows individuals to send and receive typed messages using its keyboard. Both home and public telephones can be equipped with a TDD. Public TDD pay phones have a keyboard drawer that slides out only after a call has been placed to and answered from another TDD phone so that the keyboard is protected from vandalism or other damage.

Download this free guide

Download: Overcome Virtual Network Management Challenges

The virtualized network poses challenges to network management systems -- and as more hardware components become virtualized, that challenge becomes even greater. This handbook discusses the steps IT must take to both build and corral their virtualized infrastructure.

Start Download

• Corporate E-mail Address:

  You forgot to provide an Email Address.

  This email address doesn’t appear to be valid.

  This email address is already registered. Please login.

  You have exceeded the maximum character limit.

  Please provide a Corporate E-mail Address.

By submitting my Email address I confirm that I have read and accepted the Terms of Use and Declaration of Consent.

By submitting your personal information, you agree that TechTarget and its partners may contact you regarding relevant content, products and special offers.

You also agree that your personal information may be transferred and processed in the United States, and that you have read and agree to the Terms of Use and the Privacy Policy.