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Telecommunications Relay Services

The Americans with Disabilities Act (ADA) of 1990 took full effect on July 26,1993. Title IV of the ADA requires all telephone companies across the United States to provide telecommunications relay services.

A telecommunications relay service (TRS) allows people who are deaf, hard of hearing, or speech impaired to communicate through a communications assistant (CA) with people who use a standard telephone. A CA relays the TTY (text telephone or telecommunications device for deaf and hard of hearing people) input to the telephone user and types that person’s response back to the TTY user. Telecommunications relay services can be reached by dialing 711.

Just as you can dial 411 for information, you can dial 711 to access all telecommunications relay services anywhere in the United States. The relay service is free.

CAs are trained to be as unobtrusive as possible during a call. A CA’s responsibility is to relay the conversation exactly as it is received. All relay calls are confidential.

Regardless of which long-distance company or organization is providing a state’s relay service, callers can continue to use the long-distance company of their choice.

Two options when using a telephone relay service are voice carry-over (VCO) and hearing carry-over (HCO). VCO allows a person with a hearing impairment to speak directly to the other party and then read the response typed by a CA. HCO allows a person with a speech impairment to hear the other party and relay the TTY response back to the telephone user through the CA. This service allows individuals with communication disorders to communicate with all telephone users.

For more information on telecommunications relay services, please visit the Federal Communications Commission at

NIH Publication No. 94-3754
Updated February 2004

For more information, contact the NIDCD Information Clearinghouse.