Americans With Disabilities Act: Emergency Response Systems and Telecommunications Devices for the Deaf [open pdf - 80KB]
"This Research in Action, one of a series designed to explain how the ADA will affect the criminal justice system, focuses on first steps public safety agencies should take to accommodate the 911 telephone emergency response system to handle telecommunication devices for the deaf (TDDs). ADA requires that 'telephone emergency services, including 911 services, provide direct access to people who use TDDs.' Based on a case study of the Denver emergency response system, key requirements for accommodating TDD's include: Having a TDD at every telecommunicator position where possible; establishing standard operating procedures for responding and transferring TDD calls; and testing equipment and telecommunicators regularly."
National Institute of Justice, Communications Technologies: http://www.ojp.gov/nij/topics/comtech