A TTY is a text telephone device that enables individuals who are deaf, hard of hearing or who have a speech impairment to make and receive telephone calls. The device requires two TTY users to type messages back and forth to communicate instead of talking or listening. When messages are typed on the TTY keyboard, the information is displayed on the TTY display panel and transmitted through the phone line to a receiving TTY. Another term used for TTY is TDD. TTY is an abbreviation for the phrase "Tele-Typewriter" and TDD is an abbreviation for the phrase "Telecommunication Device for the Deaf."
The Telecommunications Relay Service (TRS) is a 24 hour, 7 day a week, free relay assistance service that enables TTY access in situations where someone who uses a TTY may be calling a voice phone or vice versa. Using a TTY, Voice Carry Over phone (VCO), voice phone or videophone, an individual dials the toll-free number to contact the TRS system which will connect the caller to a communications assistant (CA). In some states it is possible to dial 711 for direct access. The CA directs the call for the individual. When the individual at the recipient end of the call answers, the CA explains his or her role in the call and from that point forward will relay the communication between the two parties, exactly as stated by both parties either in text, voice, or ASL.
It may be helpful to contact the State Assistive Technology (AT) Project for assistance in selecting a TTY. State Assistive Technology Projects are funded under the Assistive Technology Act of 1998 (P.L. 105-394). These projects can provide technical assistance on assistive technology, consultation, product demonstrations, equipment borrowing, and low-interest loans for individuals with disabilities.