It is estimated that approximately 27 million Americans have a hearing impairment. This condition affects all age groups from the newly born to teenagers, adults and the elderly. The consequences of deafness may range from minor to severe. Many individuals have a hearing loss so severe that they can not hear or understand either speech or most of the sounds from our everyday environment, even with the help of a hearing aid.

Introduction to the TDD

The telephone is a vital element in our daily living. We routinely use the phone to call friends and family, make appointments or reservations, or just inquire about something we need to know. We also use the telephone to report emergencies. For most people, the telephone provides a convenience that we take for granted. However, for the hearing impaired community, the convenience is one that has just become accessible in recent years. Today, a deaf or hearing impaired person can make a telephone call using a TDD/TTY by typing a conversation rather than speaking.

A TDD is a telecommunications device for the deaf. A TTY is a text teletype. Both of these (TDD/TTY) are the same thing in effect. They allow a hearing impaired person to communicate via the telephone. The device has a keyboard, a display and a coupler or modem that make the TDD/TTY compatible with a telephone. The party calling as well as the party called must have a TDD/TTY to communicate. Once this connection is made, the TDD/TTY users type messages back and forth.


On January 26, 1990, President Bush sign into law the Americans with Disabilities Act (ADA). The purpose of this Act is to remove the barriers that keep disabled citizens from participating in everyday events such as using the telephone to call for help. As of January 26, 1992, it is mandated that all Public Safety Answering Points (PSAPs) for 9-1-1 systems have access to a TDD and know how to operate it proficiently. Title II, Section 35.162 of the Act states: "Telephone emergency services, including 9-1-1 services, shall provide direct access to individuals who use TDDs and computer modems."  The Sherman County  9-1-1 system is equipped with TDD/TTY equipment. Communications professionals receive training in handling emergency calls using this equipment.