Impact of New Telecommunication Technologies on the Deaf

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Note to readers from 21st century

The work paper in this Web page was written during the last decade of 20th century (at 1993, to be precise). At that time, the Internet was not as widespread as it is today. In fact, at the time, in Israel it was accessible only by academic institutions and Hi-Tech companies. Regular phone lines were not used for data transfers faster than 14,400bps. Widespread use of videophones were only a wet dream. So was wide availability of information without having to make a phone call for it.

Work paper about the implications of usage of new telecommunication technologies upon the hearing impaired population in Israel

Written by:
Omer Zak
Datacomm Coordinator
Association of the Deaf in Israel
13 Yad Lebanim Ave.
61 090 Tel Aviv
Phone: +972-3-7303355
FAX: +972-3-7396419

Written at: 1993 Aug 22
Translated into English at: 1993 Nov 02

0. Comments about the English translation

  1. The Hebrew language version of the report refers to various terms which are specific to Israel. Wherever such terms appear, an explanation is added in square brackets.
  2. Political Correctness Disclaimers:
    • Wherever I refer to the masculine gender, both genders are to be implied.
    • I use the term "hearing impaired" to denote both Deaf, deaf and hard of hearing. This term is not to be understood as implying that the persons concerned are impaired in any other way.
    • I use the term TDD rather than TTY or TT.

1. Preface

Ministry of Communications [corresponding to FCC for the purpose of our discussion in that it regulates Bezeq], Bezeq [the Israeli phone company] and various private companies are involved in introduction of various new telecommunication technologies into Israel. The new technologies hold promise for dramatic improvement in the ability of the hearing impaired in Israel to communicate with other people, extract information from various databases and get information from mass communication media.

However, along with the promise, there is also the risk that due to lack of foresight when planning the deployment of the new technologies, provisions for making them accessible to the hearing impaired will not be implemented, thus keeping the hearing impaired in disadvantaged position. Example - the voice information services, which are accessible via the 056 prefix [corresponding to the 900 numbers in USA]. With a small change (to be explained below), they could have been accessible to the hearing impaired. Another example - the videophone: in order to enable a conversation in sign language, the required picture quality must be better than needed for other applications (see ref. 2, pg. 49).

This work paper reviews the telecommunication technologies, of which the author is aware. The author hopes that the contents of this work paper reach those people who design and decide about the form of new telecommunication technologies in Israel, and will help them make decisions with awareness of the specific needs of the hearing impaired in Israel.

The author wishes to acknowledge the help he got from Mrs. Hava Savir and Dr. Daniella Gabizon. They reviewed a draft version of this paper and their criticism of it was helpful in improving the final version.

3. Characteristics of the hearing impaired population in Israel

In Isarel, as in other places, few percent of the general population suffer from some type of hearing impairment. When discussing the required rehabilitation technology, it is convenient to distinguish among hard of hearing (who can communicate by means of speech, and need amplification and/or quiet environment) and the deaf (who need communication means, which are not based upon speech). Of course, this classification is not matter of black vs. white, but has lots of gray areas (such as deaf persons with good voice, and hard of hearing who need exceptional circumstances in order to make use of their hearing).

The incidence of hearing impairment among people of a particular age group increases as those people get older. At age 2-3, the incidence of deafness is about 1.3 promil (see ref. 3), and the incidence of people suffering from any hearing problem is about 5 promil. At age 7, the incidence of people suffering from any hearing problem is already 13 promil (see ref. 4). The incidence of sufferers from problems in speech and language development (due to several reasons, not limited to hearing impairment) at age 7 is 22 promil.

According to a demographic survey, it is estimated that about 1.1 promil of the general population got deafened at age less than 19 (see ref. 1, pg. 20). Among those people, about 60% have good mastery of sign language.

At age 65 and above, the incidence of people with hearing impairment is very high. Until end of writing this work paper, I got no precise data, but I'll say that one third of the elderly suffer from severe hearing impairment. Due to the general increase of percentage of the elderly among the general population, it is expected that there will be increase in percentage of those which suffer from severe hearing impairment among the general pouplation. Those persons have needs which differ from those of who got deafened at youth, since they don't master sign language and are not expected to be able to master it at old age. Besides that, they'll find it difficult to master new telecommunications equipment, unless it is designed to be user friendly.

4. Various technologies and their impact on the hearing impaired in Israel

In this chapter I'll review various telecommunication technologies and describe their impact (both beneficial and adverse) upon the hearing impaired in Israel.

4.1. Videophone

In principle, this telecommunication means can help the hearing impaired in two ways:
  1. Ability to read a slip of paper written by the other side - and so understand what is the subject matter is without having to hear him.
  2. Possibility to communicate by means of lipreading and/or sign language, because the body movements and facial gestures of the other side are seen.

In practice, the videophones, which were demonstrated by Bezeq at April 1993, are not suitable for use by the hearing impaired due to the following reasons:

  1. Low resolution - it is impossible to read a paper presented to the video camera in the other side of the conversation.
  2. Transmission rate of two frames per second - makes it impossible to communicate by means of lipreading and/or sign language.
  3. There was no provision for feedback, which would inform a person, who displays a written paper, how to position it in an optimal way relative to the video camera.

In Norway, some experiments with improved videophones were conducted (see ref. 2). Those videophones use advanced data compression techniques to enable picture transmission via a data communication channel, which operates at rate of 64Kbps (ISDN type B channel). However, the picture quality is worse than that of a standard TV set. In an experiment made with adult persons, used to working with TDDs, it was found that the adult persons prefer TDDs to videophones.

The conclusion is that when ISDN service is introduced into Israel, the infrastructure must make it possible to supply to any private person, and at reasonable cost, service which provides wider bandwidth than that supplied by the base rate service (2B+D). In addition, videophones, which provide good quality pictures, must be developed and made available to the interested, even if they require more than two B channels.

For more information about the ISDN technology, you may want to consult the following Internet resources:

  1. ISDN Primer and Technical Reference
  2. ISDN User's Guide
  3. FAQ - comp.dcom.isdn
  4. The Usenet newsgroup comp.dcom.isdn

4.2. Facsimile

The facsimile serves as the main and most successful telecommunications means among the hearing impaired population in Israel in spite of the following disadvantages:
  1. Very high cost - more expensive than color TV or VCR, due to high purchase tax levied by the government.
  2. It is impossible to conduct bidirectional conversation, and people must use the "ping-pong" approach - A sends a message to B; A waits for response from B; B sends a message to A; B waits for response from A and so on.
  3. Being literate is a prerequisite for using the facsimile for telecommunication, so this machine does not solve the problem of deaf persons who master only sign language. However, some deaf persons improvised all kinds of solutions (such as pictures/icons or fixed messages) to circumvent the need to be literate and use the facsimile nevertheless.
  4. While most of the companies and businesses have facsimiles, most of the private persons don't own one yet.

It is recommended to work with international standards organizations to define an extension to the facsimile communication standards to enable bidirectional communications, one way or the other. In addition, lobbying is needed to exempt facsimiles from any taxes when they are sold to either hearing impaired or to hearing people, who are going to use them to keep in touch with hearing impaired relatives or friends.

4.3. Modem (TDD)

[This section is very specific to Israel. No Hebrew language TDDs have been successfully marketed, and we used home or personal computer based TDDs exclusively until the facsimile took over.]

In this method, two home or personal computers are used; and a modem is connected to each computer. Using this method, the sides to the conversation each type text on his computer instead of speaking. The computer transmits the typed text via the modem to the other computer.

Each computer displays on its display the text, which was typed on that computer, along with the text arriving from the other computer via the modem. There are telecommunication programs, which display split screen, which allows separation between text typed on the same computer and text, which arrived from the other computer.

The required hardware for this method is cheaper than the facsimile and allows bidirectional communication. However, this method didn't enjoy the popularity of the facsimile due to the following reasons:

  1. The text has to be typed in quickly in order to use the connect time efficiently.
  2. The process of making connection is relatively cumbersome (need to turn on the PC, load and start the terminal software, etc.).
  3. In most of the modem installations, the modems are not installed in such a way that it is convenient to start a TDD connection without preceding it by a voice call advising the other side that a TDD call is going to arrive.

[Another factor is that Israeli schools do not teach touch typing, in contrast to American schools. So the percentage of population with touch typing skills is lower in Israel than in USA.]

In USA, the main telecommunications means of deaf persons is the TDD, since hardware, which can be used as TDD, was available for free (surplus equipment of AT&T in the sixties) and later at cost much lower than that of a facsimile.

It would be a good idea to consider the possibility of using the DOV (Data Over Voice) technology, which allows simultaneous transfer of speech and data over the same phone line. In ISDN, this can be implemented without special arrangements. Such a technology would reduce the time and effort of communications between hearing person and deaf person who has good voice. The communication mode in such a case is that the hearing person will type whatever he has to say, and the deaf person will use his voice.

4.4. Computerized information systems

Computerized information systems, which are based upon making modem connection with a central database, are equally accessible to the hearing and the hearing impaired - as long as the service is not a voice information service, or service based upon computer synthesized voice.

Since the accessibility of the hearing impaired to the regular mass communication media (radio, TV, word of mouth gossip network) is limited, it is anticipated that the hearing impaired will make use of the computerized information systems to compensate for the above lack. For this purpose, it is necessary to construct databases, which contain news from the radio and the TV; scripts of talk/interview programs from the radio and the TV (including all of its channels and this means also cable TV); explanations of terms used in the news programs, which are not familiar to hearing impaired persons who suffer also from environmental retardedness; background material about political parties, leaders, organizations etc., who are mentioned in the news.

It is to be noted that such computerized information systems will help also immigrants to Israel to get acquainted with the Israeli culture and thus help in their absorption. [Israel is an immigrant country, and during the last few years its population increased by 10% due to a wave of immigrants from the former USSR, Ethiopia and some other countries.] Therefore it is recommended that such information systems be designed to be able to deliver information in several languages, according to user's choice.

Another point to be taken into account is the design of the terminal to be used for accessing those computerized information systems. Such a terminal will probably contain a modem, a display and a keyboard. Therefore, it is possible to use it also as a TDD (see above). Thus, care must be taken so that the hearing impaired will be able to use those terminals, which will be distributed among the general population, as TDDs with no hardware changes and almost no change in the standard operating method of the terminal. I elaborated upon this point in a separate memo (see ref. 5 [enclosed as Appendix A]).

4.5. Electronic mail services

Electronic mail usage is a state in which the hearing impaired are not limited at all due to their hearing problems, but their ability is equal to that of normally hearing people with similar command of English or Hebrew.

Therefore, to reduce the gap between the hearing impaired and the hearing, it is necessary to adopt the most liberal policy possible when deciding who is permitted to use E-mail, with whom is he permitted to correspond, and what subjects is he permitted to discuss in his E-mail messages (commercial or not commercial). In short - it must be possible to use E-mail for any purpose, for which it is permissible to use the phone.

This liberal policy must be adopted for all users, and not only the hearing impaired ones, because the hearing impaired need to be able to easily establish contact with other people, regardless of whether they are hearing or hearing impaired.

4.6. Teletext

With introduction of cable TV into Israel [Cable TV is a relatively new phenomenon in Israel, less than 3 years old], tens of channels became available to the population in Israel, and each channel is capable of distributing hundreds of Teletext pages without additional cost. It makes sense to consider using Teletext to distribute the contents of databases, which are frequently used. This will reduce the cost of the telecommunications infrastructure in Israel. The cost of usage is critical especially for the hearing impaired population in Israel, because their average income is lower than that of the general population.

There are PC plug in cards which receive Teletext signals and allow the computer to "listen" to one of the channels and accumulate hundreds of Teletext pages; and then allow the user to access information of interest from the stored Teletext pages.

Another use for Teletext is to provide captioning to programs in additional languages [in Israel, all foreign language programs are open captioned in Hebrew, except for programs for preschool children, which are dubbed]. For example, it is possible, in addition to Hebrew captions, to supply captions in English, Russian (depends upon installation of Teletext decoder with Cryllic characters), etc.; and whomever is watching the program will select the desired language by specifying the desired Teletext page number.

4.7. Voice response systems (such as the Speaking Clock and some of 056 services)

Like any computerized information system which supplies its information by means of computer synthesized speech without provisions for alternate communications channel, voice response systems are totally inaccessible to those who suffer from severe hearing impairment, and some of them may be problematic even for those who suffer from slight hearing impairment.

Since there is, at any case, a computer which provides the service, it is recommended to require, by law or by regulation, that it'll be possible to access those voice response systems by means of modem and get the requested information via the modem. The computer shall be required to automatically recognize whether the user called by a Touch Tone(R) phone or by means of modem, and provide the information appropriately. This addition is not expected to increase significantly the cost of the service, because it is sufficient to use a cheap and slow modem (300 BPS is enough to provide information at speech rate). This requirement corresponds to the requirement to add ramps to public buildings in order to make them accessible to people who use wheel chairs.

In order to facilitate the identification of a calling modem, it is possible to require the caller to start his modem in Answer mode, rather than the usual Originate mode (in Hayes compatible modems, this can be accomplished by adding the letter R at end of the phone number dialled by the ATD command). The difference is that in Answer mode, the modem immediately emits carrier tone, without waiting for carrier tone from the modem at the other side of the phone line.

In the future, when the optical character recognition (OCR) technology will be sufficiently reliable, it will be possible to add another way to request information - by sending a FAX message to the appropriate service and getting the information by a FAX message from the information service. The procedure of doing so could be as follows:

  1. The user sends a FAX message which contains his FAX number.
  2. The service replies by sending a FAX message which consists of a questionnaire.
  3. The user fills the questionnaire and transmits it to the service by FAX.
  4. The information providing computer reads the questionnaire and transmits its reply by FAX.

It is not recommended to require the information service systems to add this way of information delivery, because sometimes the process of getting information requires more than one round of dialogue between the user and the information providing computer.

4.8. Alphanumeric pager

The pager is used by some of the hearing impaired to receive messages when they are far from facsimile or modem. The hearing impaired user requests his correspondents to phone the message center of the paging operating company and leave him messages there. When a message arrives, the user contacts the person, who left him the message, by another means.

The required improvement to alphanumeric paging service is that the message centers of the paging operating companies make it possible to leave messages by modem (or even by FAX) to let also hearing impaired persons leave messages to their friends (hearing impaired or others).

In addition, it is desirable to introduce a pager, which voices incoming messages, to help the sight impaired and blind people, who want to receive alphanumeric messages but cannot read them in a regular alphanumeric pager.

4.9. Wide-area network (WAN)

Those who can hear and speak - can use a cellular phone for wireless communications.

To help those who cannot hear or speak, and for those who can't justify the high cost of cellular phones [in Israel], it is recommended to introduce a system which will allow each subscriber to possess a transmitter/receiver which can transmit and receive messages using packet switching technology. Such a system will operate in manner similar to that of wireless local area network (LAN), but at lower data transfer rates and to longer ranges. The infrastructure cost of such a system would be lower, because less frequencies will be needed to serve a given number of subscribers.

Siuch a system can serve also hearing persons who don't need the full capabilities of cellular phones, thereby freeing frequencies for the use of those who really need cellular phones.

If it is not desired to deploy another telecommunications network, and the costs can be borne, it is possible to use facsimiles connected to cellular phones.

4.10. Speech recognition by computer

Computerized speech recognition systems, which translate speech into written text, are the holy grail and wet dream of several hearing impaired persons. It is possible to integrate speech recognition systems into telecommunication systems in two ways. One way will be very helpful to the hearing impaired. The other way may be problematic to those who have speech problems (most of the hearing impaired have also speech problems, which are due to imperfect feedback about the quality of their voice).

The beneficial way is to integrate a speech recognition system into the phone contact between hearing person with good voice and deaf person. The deaf person will get the information in form of text, and the hearing person will hear the deaf person's speech (or speech synthesized from text typed in by the deaf person). [This scheme is really automated relay service. In Israel, there are no relay services, and the concept is relatively unfamiliar.]

The problematic way is to use speech recognition as a replacement to the tones of TouchTone(R) telephones, modem or FAX in services, which desire to allow the calling person to give commands to a database or to a 056-type [900-type in USA] service. In order to avoid such situations, it is recommended to require, by law and/or regulations, that the capability of contacting those services by means of modem be implemented; and that the service be required to be able to automatically discriminate among voice call and modem call.

4.11. Contacting emergency dispatch centers

[I don't recall the appropriate term in English, but the idea is that elderly people have at home a special switch, which they press if some emergency happens to them. A signal is transmitted to a center, which is then able to dispatch the appropriate help to the elderly person in trouble.]

As Sela and Rimor mentioned (see ref. 6), there is a problem of using emergency dispatch centers by deaf persons, who have the medical need for such centers. [Example - centers which cater to people who have high risk of heart attack.]

Any proposed solution must take into account the following:

  1. Inability to use hearing to hear questions for more information.
  2. Inability to use speech in some cases.
  3. Bad motor abilities (i.e. inability to type a message) at worst case.
  4. Reading difficulties in some cases.

Therefore several versions of emergency switches must be developed. For someone whose abilities are poor in all the above areas, the emergency switch will be a simple switch, which when pressed will summon someone who will come and see what are the circumstances and summon the appropriate help team accordingly. In less problematic cases, it is possible to use an emergency switch witn few buttons, such that each button will transmit a different message to the emergency dispatch center.

For someone who can speak or type a message, arrangements are needed so that the user will be able to use telecommunication equipment, described in previous sections, to report his condition and so let the emergency dispatch center summon the appropriate help. Sight difficulties can be overcome by using display with large characters. Illiteracy can be overcome by displaying icons on the display and careful design of the communication procedure to be used.

APPENDIX A: Work paper - needs from the Tikshofon so that it'll meet the needs of the deaf

Written by:
Omer Zak

Written at: 1992 Dec 23
Translated into English at: 1993 Nov 2

[Tikshofon is the name given to a project, which was contemplated and announced, but later abandoned, to distribute terminals for accessing databases among the general population. The concept is similar to that of the French Minitel. Efforts are underway to develop and provide a similar service, but under other trade names.]

1. Preface

This work paper details the technical requirements, which must be considered in order to let the deaf population in Israel use the Tikshofon with minimum of unpleasant surprises. The needs of other disabled people will be mentioned, too.

2. Methods of usage by the deaf public

The expected methods of usage of Tikshofones by the deaf public (in addition to any use made by the population at large) can be characterized as follows:
  1. Conversation between two deaf persons, using two Tikshofones connected to each other by means of phone line. [i.e. the Tikshofones are being used as TDDs.]
  2. Conversation between deaf person and hearing person using two Tikshofones. The Tikshofones can maintain this conversation by using modems in both directions, or using modem in one direction (hearing person to deaf person), and speech in the other direction (deaf person to hearing person).
  3. Ability to automatically recognize the type of incoming call is necessary so that speech, FAX and Tikshofon calls can be distinguished. This is so because it is expected that several deaf persons will equip themselves with facsimiles. In addition, large percentage of deaf persons live with hearing persons, who receive regular phone calls.
  4. Ability to operate as answering machine.
  5. Ability to remember a prepared message and transmit it, using a simple and user-friendly method - is less important, because it overlaps abilities of facsimiles, which are expected to arrive at several homes of deaf persons.
  6. A visual indication of call progress is needed for those who can't hear the corresponding call progress tones.
  7. Ability (even if limited) to automatically recognize speech may be very valuable at emergencies. The Association of the Deaf can undertake the task of checking if and how to "cover" most of the possible emergency situations by 100-word vocabulary for speaker-independent speech recognition, and additional 100-word vocabulary for speaker-dependent speech recognition. I don't think that the cost of adding this capability to Tikshofon would be prohibitive.
  8. Like speech recognition, ability to synthesize speech can help at emergencies.

Therefore, it is desirable that the display of the Tikshofon will include the capability of clearly indicating to whom belongs each typed phrase (e.g. by means of split screen or color coding). In addition, if the communications standard is based upon modems with Originate and Answer modes, the Tikshofons must be able to automatically negotiate and choose which one will work in Originate mode, and which - in Answer mode. In addition, the users must be provided with ability to force a certain choice (in order to overcome phone line problems).

3. Compatibility with existing equipment

In Israel, few tens of deaf persons use TDDs to conduct phone conversations. Those TDDs are personal computers (usually Commodore 64 or IBM PC compatible) with modem and telecommunications software. If someone has a PC and modem, obtained for other purposes, he can use them as TDD without additional cost (except for obtaining the telecommunications software, and it is freely distributed).

The telecommunications standard used by Israeli TDDs was defined (by the author of this work paper) and no technical problem is expected to prevent Tikshofons from supporting this standard. A summary of the standard appears in the appendix [appendix of APPENDIX A].

4. Needs of other disabled persons

The standard Tikshofon must be designed in such a way that it'll be possible, without large expenses, to adapt it to the special needs of people who have the following disabilities (and additional disabilities, not mentioned below):
  1. Blind, sight impaired, color-blind - requirement for customizability of the display or replacing it by apparatus based upon Braille.
  2. Paralysis (including brain paralysis) - ability to type text by means other than standard keyboard.

One of the possibilities is to design the Tikshofon so that it'll be able to work also with plug-in cards of personal computers, which are widely used. This way, it'll be possible to use plug-in cards developed for personal computers also in the Tikshofon.

APPENDIX [of APPENDIX A]: Summary of the TDD standard in use in Israel

Bell 103 standard. Ability to switch between Originate and Answer modes.
Communications protocol
Fullduplex, 300BPS, 8N1 (8 data bits, no parity and one stop bit).
Character set encoding
According to Israeli standard 960 (which is based upon 7 bits). The most significant bit shall be zero. This specification means that the codes of the Hebrew letters are in range from 60h to 7Ah.
Erasure character (for correction of typing mistakes)
The characters RUBOUT (code 7Fh) and BACKSPACE (code 08h) shall make it possible to correct typing errors. It is recommended (but not obligatory) that RUBOUT will be implemented as destructive backspace, and BACKSPACE - as nondestructive backspace.
Characters for changing direction of writing (from right to left, or from left to right):
The character CTRL-R (code 12h) shall cause the direction of writing to become that which is appropriate for Hebrew (from right to left).

The character CTRL-T (code 14h) shall cause the direction of writing to become that which is appropriate for English (from left to right).

It is to be noted that contrary to bilingual word processors, the direction of writing shall NOT be automatically changed according to the language of the incoming characters. A TDD, which transmits text, may automatically add characters for changing the direction of writing. But a receiving TDD must display exactly according to received characters.

Advancing the display to a new line
The character CARRIAGE RETURN (code 0Dh), when appearing alone, shall indicate that it's time to advance to the beginning of the next line. In other words, no LINE FEED character is needed to advance to the beginning of the next row.
Last update date: 
2005 Nov 23