Visit the results of the Alliance for Telecom Industry Solutions' IVR Accessibility Forum, which presents barriers and solutions for all IVR applications, for customers with different disabilities. There is an implementation checklist for voice IVRs and TTY IVRs.
Although no clear statistics exist, it is likely that there are between 200,000 and 700,000 Baudot TTYs in use in the US. They are small devices with single line displays and keyboards. Baudot is an older telecommunications protocol, employing 5 bit FSK and a mode character to shift from letters to numbers. It is also half duplex: users alternate turns, with no simultaneous typing. A conventional “GA” (for “Go ahead”) is typed to indicate that one’s message is complete. Although TTYs can be said to be technologically obsolete, large-scale migration from Baudot to ASCII has not happened. See Recommendation F5. (There are some advantages to Baudot over ASCII. The absence of a carrier allows VCO and HCO, as well as transfers between phones, where ASCII would usually terminate the connection.)
TTYs are used by three distinct groups of people with disabilities. The first are those whose severe hearing impairment began at birth or in early childhood, before they acquired language. Many of these people refer to themselves as Deaf (with a capital letter) to indicate that they are members of a different culture, especially focusing on their use of American Sign Language. The second group consists of those people whose hearing loss is less severe, or who acquired their hearing impairment after they acquired language. They may use a TTY in concert with speech where possible. The third group includes those who do not have a hearing loss, but who, due to another disabling condition such as cerebral palsy, are not able to speak intelligibly. Some individuals in this latter group are also motor and mobility impaired.
Many TTY users are active users of telecommunications, and have commented on their interest in using voice mail and voice menus. The following section describes some barriers to their ability to do so.
TTY users report that they can place and receive TTY messages on some private VMSs without difficulty, some with occasional loss of characters, and some not at all. It is not confirmed whether public VM platforms share this variability, or whether they all can record and play back Baudot files accurately. The non-error-correcting nature of the Baudot protocol means that if a significant number of characters is lost in playback, the customer may be able to re-play the message in order to capture its meaning. If the errors enter during recording, there is no solution.
A few TTY-users currently use public voice mail systems without any TTY access features. For everyday use, they have learned to pace the menus by both counting and watching their line status indicators. Their real reported problem is not with message storage and retrieval as much as with the user interface. All system messages and prompts (how many new messages, message disposition, etc.) as well as the administrative interface (recording a new outgoing message, notification options, etc.) are all available only in spoken form.
Those platforms that have a multi-language capability, allowing different sets of voice prompts for different language-preference users, may be able to exploit this feature to provide TTY prompts. Baudot, like spoken languages, is based on audio files. No carrier is present and there is no handshaking procedure. The sole need appears to be Baudot files for all necessary system prompts and messages.
These systems are available as both ANI-driven, allowing for service from a single platform via a single access number and a subscriber database; and DNIS-driven, requiring a separate access number. Problems remain for either solution in the event of a signaling failure: customers will receive a generic voice-only prompt for the calling or called number. One solution to this problem, an integrated message, is shown below.
TTY users may prefer to use their TTY keyboard for input, rather than DTMF from a telephone keypad. This is due to the fact that many TTY users do not keep a voice telephone in parallel with their TTY, and thus have no access to a DTMF keypad. Their request is to be able to drive the VMS menus from the TTY keyboard, using Baudot characters. Another solution is for more TTY manufacturers to add DTMF capabilities into their products. Many already have this feature for dialing the call in the first place, but cannot send DTMF once the call is placed.
Many TTY users live in households with non-TTY users. This issue is one element of both the administrative and caller interfaces. There are five sub-issues:
a. TTY-only households with single mailboxes have no additional problems with the interface. They can use an integrated message. These households are most likely to operate TTYs without a voice telephone in parallel.
b. TTY-only households with multiple mailboxes need a method of prompting both their voice and TTY callers what to enter in order to put their message in the right mailbox. Callers reach a household menu, and must enter a DTMF digit to enter an individual mailbox. Currently this can be achieved through use of an integrated message. These households would have to create integrated messages for each mailbox, plus one for the household menu.
c. Mixed households with single mailboxes require a single integrated message.
d. Mixed households with multiple mailboxes have the same problem as b.
e. Households with distinctive ringing have an additional problem regarding its interoperation with voice mail. Not all switches forward the called number to the voice mail platform. Therefore the VMS is only aware of the called line’s physical line number, and cannot provide a customized outgoing message. Also, the forwarding feature cannot be turned on and off on a per-number basis. This affects TTY users who may prefer to use their TTYs as answering machines: they must set their TTY ring count lower than the line’s ring count in order to do so. There is currently no solution for this problem.
TRS
is an operator-assisted service between TTYs and voice telephones, mandated by
the Americans with Disabilities Act. In
most (80% or more) TRS calls, a deaf or hard of hearing person (typically using
a TTY) dials a toll-free number and requests that a call be made to a hearing
person (voice party). The TRS operator
(called a “Communication Assistant” or “CA”) places the outbound call on a
second line. The conversation between
the TTY user and the voice party takes place with the assistance of the
operator, who speaks the typed messages for the benefit of the voice party, and
who types the spoken messages for the benefit of the TTY user. There are two variants from the standard TRS
call. In one, called Voice Carryover
(VCO), the TTY user speaks during his/her turn, but reads the reply from the CA
on the display. This service is useful
for those people who cannot hear phone conversation, but can speak and prefer
to do so, and those who cannot type well.
In the other, called Hearing Carryover (HCO), the TTY user types his or
her message (which is read off by the CA), but hears the spoken reply. This is useful for people who can hear and
type but are speech impaired.
Currently some state TRS providers allow TTY users to access voice mail via a TRS call. However, this can be unsatisfactory to both the TTY user and the TRS provider. As with IVR systems, the rate of speech is often faster than the Communication Assistant's typing speed. In this case, messages must be replayed to be fully transcribed, and the CA does not always know how to replay the message. This may result in loss of messages, or loss of content, or multiple calls into the VMS platform.
Integrated messages contain both Baudot (TTY text) and voice content in such a way that both voice- and TTY-users can be served from a single voice file. They are constructed as follows:
1. The Baudot letters “HD” or “HLD”, which are understood by TTY users to mean “Hold.” This will secure the attention of any TTY users, while being short enough (less than 0.5 seconds) not to confuse or inconvenience hearing callers.
2. Any standard voice message, whether or not it requires a DTMF reply. An option is to advise hearing callers to enter a DTMF digit to bypass the Baudot.
3. A pause sufficient to convince hearing callers that there is no more information to be heard, approximately 5 seconds. Presumably hearing callers will reply or hang up.
4. The appropriate transcription of the voice message in Baudot.
Integrated messages can be constructed by using both a TTY and a voice telephone on the same line, or by editing the two separate audio sources into one file.
NOTE: This may extend the duration of the message significantly. Repeating or cycling of the message may be required in some contexts.