Americans with Disabilities Act (ADA) of 1990 (with amendments issued through 2008)

(3) Telecommunications relay services

The term "telecommunications relay services" means telephone transmission relay services that provide the ability for an individual who has a hearing impairment or speech impairment to engage in communication by wire or radio with a hearing individual in a manner that is functionally equivalent to the ability of an individual who does not have a hearing impairment or speech impairment to communicate using voice communication services by wire or radio. Such term includes services that enable two-way communication between an individual who uses a TDD or other nonvoice terminal device and an individual who does not use such a device.