Introduction 1-7
101–1477–001
Edition 2
TDD/TTY Support
TDD/TTY as a mailbox language is supported in Aria 1.2. When this language is installed,
hearing- and speech-impaired subscribers can use voice mail and messaging. They use a
Telecommunications Device for the Deaf (TDD) to display text that is equivalent to voice
prompts and to process messages.
A TDD has a keyboard and a display. Like a TeleType (TTY), a TDD receives Baudot tones sent
to it over standard telephone lines and it translates the tones into the corresponding characters for
display. The TDD also generates and transmits Baudot tones for each character typed on its
keyboard. (Octel does not supply TDDs.)
To communicate by telephone with someone who can speak and hear but does not have a TDD, a
hearing- or speech-impaired person with a TDD works with a special operator who has a TDD
and who serves as an “interpreter.” The text typed by the hearing-impaired person is transmitted
as Baudot tones and displayed on the operator’s TDD; the operator then reads it aloud to the
hearing/speaking person. The operator also types the hearing/speaking person’s speech for
transmission to and display on the hearing-impaired person’s TDD. If both people in the call have
TDDs, the TDDs are connected directly to each other during the call, without using an operator.
Messages in the form of Baudot tones can be stored in voice mailboxes and subsequently
retrieved by hearing-impaired people for display on their TDDs. However, when they call the
server, their hearing impairment can prevent them from hearing its voice prompts. To address this
limitation, Aria 1.2 software supports Baudot tones as a new “language” that the system manager
establishes in the subscriber’s mailbox profile. For this language, all phrases supported by Aria
1.2 are recorded in Baudot tones so that, when hearing-impaired subscribers reach their
TDD/TTY mailboxes or a TDD/TTY application, they see the prompts on their TDD displays.
No operator interaction is required to access the message server.
Aria 1.2 software does not translate voice messages to text or text to voice. Hearing- and
speech-impaired users still need assistance with voice messages recorded in their TDD/TTY
mailboxes.
Some TDD/TTY devices use acoustic couplers that allow users to send touch-tones by pressing
keys on the standard telephone set. Other TDD/TTY devices have a special “tone” key that
determines whether numbers pressed on the TDD keyboard are to be transmitted as part of text
or as touch-tones. Users of TDD/TTY mailboxes need to know that numbers in the body of a
message must be typed as text, and numbers that are responses to server prompts must be sent as
touch-tones in “tone” (DTMF) mode. Users who do not have acoustic couplers might have
difficulty using dial-by-name; they would need to determine and enter the touch-tone digit that
corresponds to each letter in the name.
Language type 24 has been redefined as American English (TDD/TTY) in menus 20.4.1, Phrase
Table Initialization and 20.4.3, Set Language Type.
Servers must have Aria 1.2 software installed before you can add the TDD/TTY language. Use a
master drive to add the TDD/TTY language. If several languages are to be added, add TDD/TTY
last.
