The Telecommunications Device for the Deaf (TDD) is a telephony device with a QWERTY keyboard and a small display and, optionally, a printer. Instead of speaking into a mouthpiece, the caller types messages on the keyboard; instead of hearing a voice from the receiver, the caller views the messages on the screen, and can print them for later reading. Usually, at both ends of the conversation, TDDs are being used.
Although the TDD itself does not generate DTMF tones, most users use a TDD in conjunction with a telephone that generates tones, and probably think of the whole thing as a TDD.
TDD support can be ordered as an optional feature of Blueworx Voice Response.
Blueworx Voice Response’s support is designed to operate with devices meeting the EIA Standard Project PN-1663 TDD Draft, 9 June 1986 specification.