Internet Engineering Task Force                         SIPPING WG
Internet Draft                                          Charlton/Gasson/
Document: draft-ietf-sipping-deaf-req-02.txt            Gybels/Spanner/
April 2002                                              van Wijk
Expires: October 2002                                   RNID/Ericsson
Category: Informational



 User Requirements for the Session Initiation Protocol (SIP) in support
       of deaf, hard of hearing and speech-impaired individuals



Status of this Memo

This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC 2026.
Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF), its areas, and its working groups. Note that other groups
may also distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference material
or to cite them other than as "work in progress."

The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.

Table of Contents

1. Abstract............................................................2
2. Terminology and Conventions Used in this Document...................2
3. Introduction........................................................3
4. Purpose and Scope...................................................3
5. Background..........................................................4
6. Deaf, Hard of Hearing and Speech-impaired Requirements for SIP......4
   Introduction........................................................4
   6.1. Connection without Difficulty..................................5
   6.2 User Profile....................................................5
   6.3 Intelligent Gateways............................................5
   6.4 Inclusive Design................................................6
   6.5 Resource Management.............................................6
   6.6 Confidentiality and Security....................................6
7. Some Real World Scenarios...........................................6
   7.1 Transcoding Service.............................................7
   7.2 Media Service Provider..........................................7
   7.3 Sign Language Interface.........................................8
   7.4 Synthetic Lip-reading Support for Voice Calls...................8
   7.5 Voice-Activated Menu Systems....................................8
   7.6 Conference call.................................................9
8. Some Suggestions for Service Providers and User Agent
   Manufacturers......................................................10

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9. Acknowledgements...................................................11
10.Author's Addresses.................................................11
   Normative References...............................................12
   Informational References...........................................12
   Full Copyright Statement...........................................12

1. Abstract

This document aims to present a set of SIP user requirements that
support communications for deaf, hard of hearing and speech-impaired
individuals. These user requirements address the current difficulties
of deaf, hard of hearing and speech-impaired individuals in using
communications facilities, while acknowledging the multi-functional
potential of SIP-based communications.

A number of issues related to these user requirements are further
raised in this document.

Also included are some real world scenarios and some technical
requirements to show the robustness of these requirements on a
concept-level.

2. Terminology and Conventions Used in this Document

In this document, the key words "MUST", "MUST NOT","REQUIRED", "SHALL",
"SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
"OPTIONAL" are to be interpreted as described in RFC2119[1] and
indicate requirement levels for compliant SIP implementations.

For the purposes of this document, the following terms are considered to
have these meanings:

Abilities: A person's capacity for communicating which could include a
hearing or speech impairment or not. The terms Abilities and Preferences
apply to both caller and call-recipient.

Preferences: A person's choice of communication mode. This could include
any combination of media stream, e.g., text, audio, video.

The terms Abilities and Preferences apply to both caller and call-
recipient.

Relay Service: A third-party or intermediary that enables communications
between deaf, hard of hearing and speech-impaired people, and people
without hearing or speech-impairment. Relay Services form a subset of
the activities of Transcoding Services (see definition).

Transcoding Services: A human or automated third party acting as an
intermediary in any session between two other User Agents (being a User
Agent itself), and transcoding one stream into another (e.g., voice to
text or vice versa).


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Textphone: Sometimes called a TTY (teletypewriter), TDD
(telecommunications device for the deaf) or a minicom, a textphone
enables a deaf, hard of hearing or speech-impaired person to place a
call to a telephone or another textphone. Some textphones use the V18[3]
protocol as a standard for communication with other textphone
communication protocols world-wide.

User: A deaf, hard of hearing or speech-impaired individual. A user is
otherwise referred to as a person or individual, and users referred to
as people.

Note: For the purposes of this document, a deaf, hard of hearing, or
speech-impaired person is an individual who chooses to use SIP because
it can minimize or eliminate constraints in using common communication
devices. As SIP promises a total communication solution for any kind of
person, regardless of ability and preference, therefore there is no
attempt to specifically define deaf, hard of hearing or speech-impaired
in this document.

3. Introduction

The background for this document is the recent developments of SIP[2]
and SIP-based communications, and a growing awareness of deaf, hard of
hearing and speech-impaired issues in the technical community.

The SIP capacity to simplify setting up, managing and tearing down
communication sessions between all kinds of User Agents has specific
implications for deaf, hard of hearing and speech-impaired individuals.

As SIP enables multiple sessions with translation between multiple types
of media, these requirements aim to provide the standard for recognising
and enabling these interactions, and for a communications model that
includes any and all types of SIP-networking abilities and preferences.

4. Purpose and Scope

The scope of this document is to first present a current set of user
requirements for deaf, hard of hearing and speech-impaired individuals
through SIP-enabled communications. These are then followed by some real
world scenarios in SIP-communications that could be used in a test
environment, and some concepts on how these requirements can be
developed by service providers and User Agent manufacturers.

These recommendations make explicit the needs of a currently often
disadvantaged user-group and attempts to match them with the capacity of
SIP. It is also not the intention here to prioritise the needs of the
deaf, hard of hearing and speech-impaired in a way that would penalise
other individuals.

These requirements aim to encourage developers and manufacturers
world-wide to consider the specific needs of deaf, hard of hearing and
speech-impaired individuals. This document presents a world-vision

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where deafness, hard of hearing or speech impairment are no longer a
barrier to communication.

5. Background

Deaf, hard of hearing and speech-impaired people are currently sometimes
unable to use commonly available communication devices.
Although this is documented[4], this does not mean that developers or
manufacturers are always aware of this. Communication devices for the
deaf, hard of hearing and speech-impaired (e.g., text-phones) are
currently often primitive in design, expensive, and non-compatible with
progressively designed, cheaper and more adaptable communication devices
for other individuals. For example, even though some text- phones use
the V18 protocol to enable communications with other text-phones across
national and regional areas, many are limited in their compatibility
with other communication devices in their particular country or region.

Additionally, non-technical human communications for (sign languages,
lip-reading) are non-standard around the world.

There are intermediary or third-party relay services (e.g. transcoding
services) that facilitate communications, uni- or bi-directional,
for the deaf, hard of hearing and speech-impaired. Currently Relay
services are mostly operator-assisted (manual), although methods of
partial automation are being implemented in some areas. These services
enable full access to modern facilities and conveniences for the deaf,
hard of hearing and speech-impaired. Although these services are
somewhat limited, their value is undeniable as compared to their
previous complete unavailability.

Yet communication methods in recent decades have proliferated: email,
mobile phones, video streaming, etc. These methods are an advance in the
development of data transfer technologies between devices.

Developers and advocates of SIP agree that this is a protocol that not
only anticipates the growth in communications between convergent
networks in real time, but also fulfils the potential of the Internet
as a communications and information forum. Further, that these
developments allow a standard of communication that can be applied
throughout all networking communities, regardless of abilities and
preferences.

6. Deaf, Hard of Hearing and Speech-impaired Requirements for SIP

Introduction

The user requirements in this section are provided for the benefit of
service providers, User Agent manufacturers and any other interested
party in the development of products and services for the deaf, hard of
hearing and speech-impaired.

The user requirements are as follows:

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6.1 Connection without Difficulty

This requirement states:

Whatever the preferences and abilities of the user and User Agent, there
SHOULD be no difficulty in setting up SIP sessions. These sessions could
include multiple proxies, call routing decisions, transcoding services,
e.g., the relay service TypeTalk[5] or other media processing, and could
include multiple simultaneous or alternative media streams.

This means that any User Agent in the conversation (including
transcoding services) MUST be able to add or remove a media stream from
the call without having to tear it down and re-establish it.

6.2 User Profile

This requirement states:

Deaf, hard of hearing and speech-impaired user abilities and preferences
(i.e., user profile) MUST be communicable by SIP, and these abilities
and preferences MUST determine the handling of the session.

The User Profile for a deaf, hard of hearing and speech-impaired person
might include:
- How media streams are received and transmitted (text, voice, video, or
  any combination, uni- or bi-directional)
- Redirecting specific media streams through a transcoding service
  (e.g.,the relay service TypeTalk)
- Roaming (e.g., a deaf person accessing their User Profile from a web-
  interface at an Internet cafe)
- Anonymity, that is, not revealing that a deaf person is calling, even
  through a transcoding service (e.g., some relay services like
  TextDirect inform the call-recipient that there is an incoming text
  call without saying that a deaf person is calling).

Part of this requirement is to ensure that deaf, hard of hearing and
speech-impaired people can keep their preferences and abilities
confidential from others, to avoid possible discrimination or prejudice,
while still being able to establish a SIP session.

6.3 Intelligent Gateways

This requirement states:

SIP SHOULD support a class of User Agents to perform as gateways for
legacy systems designed for deaf, hard of hearing and speech-impaired
people.

For example, an individual could have a SIP User Agent acting as a
gateway to a PSTN legacy textphone.



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6.4 Inclusive Design

This requirement states:

Where applicable, design concepts for communications (devices,
applications, etc.) MUST include the abilities and preferences of deaf,
hard of hearing and speech-impaired people.
Transcoding services and User Agents MUST be able to connect with each
other regardless of the provider or manufacturer. This means that new
User Agents MUST be able to support legacy protocols through appropriate
gateways.

6.5 Resource Management

This requirement states:

User Agents SHOULD be able to identify the content of a media stream in
order to obtain such information as the cost of the media stream, if a
transcoding service can support it, etc.

User Agents SHOULD be able to choose among transcoding services and
similar services based on their capabilities (e.g., whether a
transcoding service carries a particular media stream), and any policy
constraints they impose (e.g., charging for use). It SHOULD be possible
for User Agents to discover the availability of alternative media
streams and to choose from them.

6.6 Confidentiality and Security

This requirement states:

All third-party or intermediaries (transcoding services) employed in a
session for deaf, hard of hearing and speech-impaired people MUST offer
a confidentiality policy. All information exchanged in this type of
session SHOULD be secure, that is, erased before confidentiality is
breached, unless otherwise required.

This means that transcoding services (e.g., interpretation, translation)
MUST publish their confidentiality and security policies.

7. Some Real World Scenarios

These scenarios are intended to show some of the various types of media
streams that would be initiated, managed, directed, and terminated in a
SIP-enabled network, and shows how some resources might be managed
between SIP-enabled networks, transcoding services and service
providers.

To illustrate the communications dynamic of these kinds of scenarios,
each one specifically mentions the kind of media streams transmitted,
and whether User Agents and Transcoding Services are involved.


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7.1 Transcoding Service

In this scenario, a hearing person calls the household of a deaf person
and a hearing person.

1. A voice conversation is initiated between the hearing participants:
   ( Phone A) <-----Voice ---> ( Phone B)
2. During the conversation, the hearing person asks to talk with the
   deaf person, while keeping the voice connection open so that voice to
   voice communications can continue if required.
3. A Relay Service is invited into the conversation.
4. The Relay Service transcodes the hearing person's words into text.
5. Text from the hearing person's voice appears on the display of the
   deaf person's User Agent.
6. The deaf person types a response.
7. The Relay Service receives the text and reads it to the hearing
   person:
   (        ) <------------------Voice----------------> (        )
   (Phone A ) -----Voice---> ( Voice To Text  ) -Text-> (Phone B )
   (        ) <----Voice---- (Service Provider) <-Text- (        )
8. The hearing person asks to talk with the hearing person on the other
   side.
9. The Relay Service withdraws from the call.

7.2 Media Service Provider

In this scenario, a deaf person wishes to listen to a Radio program
through a text stream of the program's audio stream.

1. The deaf person attempts to establish a connection to the radio
   broadcast, with User Agent preferences set to receiving audio stream
   as text.
2. The User Agent of the deaf person queries the radio station User
   Agent on whether a text stream is available, other than the audio
   stream.
3. However, the radio station has no text stream available for a deaf
   listener, and responds in the negative.
4. As no text stream is available, the deaf person's User Agent requests
   a Voice-To-Text transcoding service (e.g., a real-time captioning
   service like TypeTalk) to come into the conversation space.
5. The transcoding service User Agent identifies the audio stream as a
   radio broadcast. However, the policy of the transcoding service is
   that it does not accept radio broadcasts because it would overload
   their resources far too quickly.
6. In this case, the connection fails.

Alternatively, continuing from 2 above:
3. The radio station does provide text with their audio streams.
4. The deaf person receives a text stream of the radio program.

Note: To support deaf, hard of hearing and speech-impaired, service
      providers are encouraged to provide text with audio streams.

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7.3 Sign Language Interface

In this scenario, a deaf person enables a signing avatar (e.g.,
VisiCAST[6]) by setting up a User Agent to receive audio streams as XML
data that will operate an avatar for sign-language. For outgoing
communications, the deaf person types text that is transcoded into an
audio stream for the other conversation participant.

 For example:
 (         )-Voice->(Voice To Synthetic Signing) --XMLData-->(        )
 ( hearing )                                                 (deaf    )
 ( Party A )<-Voice-( Text To Voice  ) <--------Text-------- (Party B )
 (         )        (Service Provider)                       (        )

7.4 Synthetic Lip-speaking Support for Voice Calls

In order to receive voice calls, a hard of hearing person uses a
synthetic lip-speaking avatar software (e.g., Synface[7]) on a PC. The
synthetic lip-speaking software processes voice (audio) stream data and
displays an animated face that a hard of hearing person may be able to
lip-read. During a conversation, the hard of hearing person uses the
synthetic lip-speaking software as support for understanding the audio
stream.

For example:
(         ) <-----Voice-----> ( hard of ) -Voice-> ( PC with     )
( hearing )                   ( hearing )          ( lip-speaking)
( Party A )                   ( party B )          ( software    )

7.5 Voice Activated Menu Systems

In this scenario, a deaf person wishing to book cinema tickets with a
credit card, using a text phone to place the call. The cinema employs a
voice-activated menu system for film titles and showing times.

1. The deaf person places a call to the cinema with a text-phone:
   (Text-phone) <-----Text ---> (Voice-activated System)
2. The cinema's voice-activated menu requests an auditory response to
   continue.
3. A Relay Service is invited into the conversation.
4. The Relay Service transcodes the prompts of the voice-activated menu
   into text.
5. Text from the voice-activated menu appears on the display of the deaf
   person's text-phone.
6. The deaf person types a response.
7. The Relay Service receives the text and reads it to the voice-
   activated system:
   (           )         (Relay Service   )          (               )
   (Text-phone ) -Text-> (Provider        ) -Voice-> (Voice-Activated)
   (           ) <-Text- (Text To Voice   ) <-Voice- (System         )
8. The transaction is finalised with a confirmed booking time.
9. The Relay Service withdraws from the call.

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7.6 Conference Call

A conference call is scheduled between five persons:

- Person A listens and types text (hearing, no speech)
- Person B recognises sign language and signs back (deaf, no speech)
- Person C reads text and speaks (deaf or hearing impaired)
- Person D listens and speaks
- Person E recognises sign language and reads text and signs

A conference call server calls the five people and based on their pre-
ferences sets up the different transcoding services required. Assuming
English is the base language for the call, the following intermediate
transcoding services are invoked:

- A transcoding service (English speech to English text)
- An English text to sign language service
- A sign language to English text service
- An English text to English speech service

Note: In order to translate from English speech to sign language, a
chain of intermediate transcoding services is used (transcoding and
English text to sign language) because there was no speech-to-sign
language available for direct translation. The same applies for the
translation from sign language to English speech accordingly.

(Person A) ----- Text ----> (  Text-to-SL  ) --- Video ----> (Person B)
           ---------------------- Text --------------------> (Person C)
           ----- Text ----> (Text-to-Speech) --- Voice ----> (Person D)
           ---------------------- Text --------------------> (Person E)
           ----- Text ----> (  Text-to-SL  ) --- Video ----> (Person E)
(Person B) -Video-> (SL-to-Text) -Text-> (Text-to-Speech) -> (Person A)
           ---- Video ----> (  SL-to-Text  ) ---- Text ----> (Person C)
           -Video-> (SL-to-Text) -Text-> (Text-to-Speech) -> (Person D)
           --------------------- Video --------------------> (Person E)
           ---- Video ----> (  SL-to-Text  ) ---- Text ----> (Person E)
(Person C) --------------------- Voice --------------------> (Person A)
           Voice->(Speech-to-Text)-Text->(Text-to-SL)-Video->(Person B)
           --------------------- Voice --------------------> (Person D)
           ---- Voice ----> (Speech-to-Text) ---- Text ----> (Person E)
           Voice->(Speech-to-Text)-Text->(Text-to-SL)-Video->(Person E)
(Person D) --------------------- Voice --------------------> (Person A)
           Voice->(Speech-to-Text)-Text->(Text-to-SL)-Video->(Person B)
           ---- Voice ----> (Speech-to-Text) ---- Text ----> (Person C)
           ---- Voice ----> (Speech-to-Text) ---- Text ----> (Person E)
           Voice->(Speech-to-Text)-Text->(Text-to-SL)-Video->(Person E)
(Person E) -Video-> (SL-to-Text) -Text-> (Text-to-Speech) -> (Person A)
           --------------------- Video --------------------> (person B)
           ---- Video ----> (  SL-to-Text  ) ---- Text ----> (Person C)
           -Video-> (SL-to-Text) -Text-> (Text-to-Speech) -> (Person D)



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Remarks: - Some services might be shared by users and/or other
           services.
         - Person E uses two parallel streams (SL and English Text).
           The User Agent might perform time synchronisation when dis-
           playing the streams. However, this would require synchroni-
           sation information to be present on the streams.
         - The session protocols MIGHT support optional buffering of
           media streams, so that users and/or intermediate services
           could go back to previous content or to invoke a transcoding
           service for content they just missed.
         - Hearing impaired users might still receive audio as well,
           which they will use to drive some visual indicators so that
           they can better see where for instance the pauses are in the
           conversation.


8. Some Suggestions for Service Providers and User Agent Manufacturers

This section is included to encourage service providers and user agent
manufacturers in developing products and services that can be used by as
wide a range of individuals as possible, including the deaf, hard of
hearing and speech-impaired.

- Service providers and User Agent manufacturers can offer to a deaf,
  hard of hearing and speech-impaired person the possibility of being
  able to hide their specific references and abilities from being made
  public in any transaction.
- If a User Agent performs auditory signalling, for example a pager, it
  could also provide another signalling method; visual (flashing light)
  or tactile (vibration).
- Service providers who allow the user to store specific setting or
  preferences and abilities (i.e., user profile) might consider storing
  these setting in a central repository, accessible no matter the
  location of the user and regardless of the User Agent used at that
  time or location.
- If there are several transcoding services available, the User Agent
  can be set to select the most economical/highest quality service.
- The service provider can show the cost per minute and any minimum
  charge of a transcoding service call before a session starts, allowing
  the user a choice of engaging in the service or not.
- Service providers are encouraged to offer an alternative stream with
  audio streams, for example, text or data streams that operate avatars,
  etc.
- Service providers are encouraged to provide a text alternative to
  voice-activated menus, e.g., answering and voice mail systems.
- Manufacturers of voice-activated software are encouraged to provide an
  alternative visual format for software prompts, menus, messages, and
  status information.
- Manufacturers of mobile phones are encouraged to develop equipment
  design in which radio wave signals do not interfere with hearing aids.



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- All services for interpreting, transliterating, or facilitating
  communications for deaf, hard of hearing and speech-impaired people
  are required to:
  - Keep information exchanged during the transaction strictly
    confidential
  - Enable information exchange literally and simply, without deviating
    and compromising the content
  - Facilitate communication without bias, prejudice or opinion
  - Match skill sets to the requirement of the individual
  - Behave in a professional and appropriate manner
  - Be fair in claiming compensation for services
  - Strive to improve the skill-sets used for their services.
- Conference calling services might consider ways to allow users to
  employ transcoding services (which usually introduce a delay) to have
  real-time information sufficient to be able to identify gaps in the
  conversation so they could inject comments, as well as ways to raise
  their hand, vote and carry out other activities where timing of their
  response relative to the real-time conversation is important.

9. Acknowledgements

The authors would like to thank the following individuals for their
contributions to this draft:

David R. Oran, Cisco
Mark Watson, Nortel Networks
Brian Grover, RNID
Anthony Rabin, RNID
Michael Hammer, Cisco
Henry Sinnreich, Worldcom
Rohan Mahy, Cisco
Julian Branston, Cedalion Hosting Services
Judy Harkins, Gallaudet University, Washington, D.C.
Cary Barbin, Gallaudet University, Washington, D.C.
Gregg Vanderheiden, Trace R&D Center University of Wisconsin-Madison
Gottfried Zimmerman, Trace R&D Center University of Wisconsin-Madison

10. Author's Addresses

Nathan Charlton, RNID, nathan.charlton@rnid.org.uk
Mick Gasson, RNID, mike.gasson@rnid.org.uk
Guido Gybels, RNID, Guido.Gybels@rnid.org.uk
Mike Spanner, RNID, mike.spanner@rnid.org.uk
19-23 Featherstone Street
London EC1Y 8SL
Tel: +44-20 7296 8000
Textphone: +44-20 7296 8001
Fax: +44-20 7296 8199





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Arnoud van Wijk
Ericsson EuroLab Netherlands BV
P.O. Box 8
5120 AA Rijen
The Netherlands
Fax: +31-161-247569
Email: Arnoud.van.Wijk@eln.ericsson.se

Comments can be sent to the SIPPING mailing list.


Normative References

[1] S. Bradner, "Key words for use in RFCs to indicate requirement
    levels". Request for Comments 2119, Internet Engineering Task Force.
    March 1997.

[2] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
    Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP: Session
    Initiation Protocol", draft-ietf-sip-rfc2543bis-09 (work in
    progress), February 2002.


Informational References

[3] International Telecommunication Union (ITU), "Operational and
    interworking requirements for DCEs operating in the text telephone
    mode". ITU-T Recommendation V.18, November 2000.

[4] Moore, Matthew, et al. "For Hearing People Only: Answers to Some of
    the Most Commonly Asked Questions About the Deaf Community, Its
    Culture, and the Deaf Reality". MSM Productions Ltd., 2nd Edition,
    September 1993.

[5] http://www.typetalk.org.

[6] http://www.visicast.co.uk.

[7] http://www.speech.kth.se/teleface.




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in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are included
on all such copies and derivative works. However, this document itself

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may not be modified in any way, such as by removing the copyright notice
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Expires: October 2002

































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