Internet DRAFT - draft-gearhart-sip-deaf-req
draft-gearhart-sip-deaf-req
Internet Engineering Task Force SIP WG
Internet Draft Gearhart/van Wijk/
Document: <draft-gearhart-sip-deaf-req-00.txt> Sinnreich
November 2000 Ericsson/WCOM
Expires: April 2001
A Proposed Set of Requirements for SIP Support for Deaf or Speech
Impaired Customers
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026 [1].
Internet-Drafts are working documents of the Internet Engineering
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The list of current Internet-Drafts can be accessed at
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The list of Internet-Draft Shadow Directories can be accessed at
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1. Abstract
SIP is attracting more and more attention as a valuable tool to
enable and support voice and multimedia communications over the
Internet. However, a significant number of potential customers
for SIP-based services are for various reasons unable to, or
choose not to, use voice communication technologies. This document
offers a proposed set of requirements and identifies some of the
key issues that need resolution to allow full accessibility for
this group to SIP-based Internet communications. This document is
intended to continue the discussion begun in a previous draft (see
Acknowledgements) and to lay a foundation for design and
implementation discussions in future drafts.
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 RFC
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2119 [2] and indicate requirement levels for compliant SIP
implementations.
For the purposes of this document, the term ôUser Equipmentö
(ôUEö) will be used to represent the Deaf individual and his/her
SIP-enabled UA end-user equipment; this could be a TTY[3], a
personal computer or PDA, a specially equipped mobile phone, video
phone, etc.
The term ôuserö, in this document, shall be understood to mean a
Deaf/deaf/hard-of-hearing individual.
3. Introduction
The Session Initiation Protocol (SIP)[4] is used to initiate,
modify, and terminate interactive sessions between sets of users.
Typically these are voice sessions, described by the Session
Description Protocol (SDP)[5]. However not all customers or
potential customers have access to these SIP services.
Specifically, people who consider themselves culturally Deaf[6],
audiologically deaf[7], hard of hearing, speech impaired or
disabled, etc., on either a temporary or permanent basis, are
unable to participate in these voice-based communications.
For the purposes of this document, this group of people will be
referred to collectively as "Deaf" individuals. Also, the term
ôASLö (American Sign Language)[8], is used in this document to
refer to the natural signed language used by culturally Deaf
people in the United States and parts of Canada and Mexico. For
Deaf individuals in other countries, ôASLö when used in this
document should be understood to refer to the local sign language
used by those people. Also, since Deaf people can and do use
various types of manual communications systems in addition to ASL
û such as Signed English û for this document the term ôASLö will
be assumed to cover all forms of manual communications.
Within the Public Switched Telephone System (PSTN), services have
been defined that allow for access to circuit switched voice
services by these customers. We believe it is important to offer
these services in an IP context. The flexibility of SIP affords us
the ability to both offer and improve on these services, and to
offer more extensive forms of universal service access to this
group of customers. This is a formative time for the future of
IP-based communications and as such it is an appropriate time to
ensure that such requirements as are necessary to ensure full
accessibility by all customers are included in planning the new 3G
network.
4. Purpose and Scope
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This document offers a proposed set of requirements and attempts
to identify issues that need resolution to allow full
accessibility for all customers to SIP-based Internet
communications.
It will outline a few possible scenarios that enable universal
access of voice and multimedia sessions, initiated by SIP, to
users who are Deaf. These services are generally enabled by
baseline SIP[1], or through the use of the caller preferences
specification[9]. No additional extensions are proposed here in
order to support universal access.
5. Background
In the current telephony world, most Deaf individuals have access
to either standalone or PC-based TTY devices. These text-based
devices or software packages are adequate for communication with
other Deaf individuals or with hearing individuals that have
similar devices or software. In addition, most if not all states
in the United States have state-sponsored Relay service, in which
a human operator with both standard telephone equipment and TTY
devices acts as a go-between ("relay operator" or interpreter),
allowing a Deaf person with a TTY to place or receive calls from
hearing individuals with standard telephones. Individuals with
speech difficulties that render it impossible for the individual
to use ordinary voice-enabled devices can use the same TTY
equipment and relay services.
Introduction of the relay service has been a great benefit to both
Deaf and hearing people because it has enabled communication
between them, where, prior to this time, it was difficult or
impossible. It has provided independence to Deaf people, allowing
them to communicate on their own terms rather than being forced to
rely on hearing friends to act as telephone interpreters.
In recent years, other technology such as two-way email pagers
have become available that provide portable communications for
Deaf people in a manner similar to cellular telephones for hearing
people. These have provided a great benefit to Deaf people,
allowing them the ease of near-instant communications that hearing
people now take for granted. Some email pager services have also
supported interface with other devices such as TTYs and FAX. In
addition, most European GSM phones offer SMS (short message
service) for exchanging short messages to other GSM subscribers.
This will also allow Deaf people to communicate near-instantly.
Most recently, the advent of video relay services has provided
ways for Deaf individuals to converse with hearing individuals
using their most natural means of communication, visual, through
the use of an oral or sign language interpreter. The human
interpreter is typically physically located at the relay center
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and provides interpreting services via video connection to the
Deaf person and voice connection to the hearing person.
Much of what is included in this draft presupposes at least a
superficial knowledge on the part of the reader of the Deaf world
and the communication problems that have been endemic in that
population since the creation of voice-only, long-distance
communications. This may not be realistic, so the authors
recommend the following books as supplemental readings for those
readers who would like to know more.
1. Baker, Charlotte, and Robbin Battison. "Sign Language and the
Deaf Community: Essays in Honor of William Stokoe". National
Association of the Deaf, June 1980.
2. 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 æDeaf RealityÆ". MSM Productions
Ltd., 2nd Edition, September 1993.
3. Padden, Carol, and Tom Humphries. "Deaf in America: Voices
from a Culture". Harvard University Press, Reprint September 1990.
4. Stokoe, William. "Sign and Culture: A Reader for Students of
American Sign Language". Linstok Press, June 1980.
6. General Requirements
This section contains a list of general requirements that have
been identified as important to ensure full accessibility to the
3G networks of the future. The relay center described above is a
key part of the proposed solution.
1. The UE MUST be able to receive relay calls any time and any
location. This capability is already included in SIP. The user
preferences in the REGISTER will indicate what relay
requirements are desired (at minimum text support MUST be
supported). Upon logging in, the UE SHOULD be able to
automatically download all user settings.
2. The UE MUST be able to set up user preferences easily to
specify language, mode of relay (such as: ASL/video to/from
speech, text to/from video or speech, also as an extended
service English to i.e. Spanish text, relay can cross language
barriers if supported). This is pre-set, but it can be
overruled by one button or via a short list with alternative
options. The UE and relay center SHOULD be able to
enable/deliver services like a "real-time closed captioning"
where the UE receives the video/audio of a caller/called, but
the relay center will translate the audio and display the text
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as subtitles. This will also offer possibilities like
commercial translation service (via voice-over or text).
3. The UE MUST be able to receive the correct Caller-ID of the
caller that calls the DP via the relay and not the relay's
Caller-ID (note: this is the caller ID and not the SIP Call-
ID).
4. The UE MUST be able to specify which pre-defined numbers
require the use of relay service and which are direct calls
(TTY to TTY, video to video) and do not require relay.
5. The UE MUST be able to download and upload the user settings
and the address book, which should be stored as a database file
at a centrally located server, which can be the relay center or
the home provider of the UE.
6. It SHOULD be possible for a user to store user preferences and
settings on a web service, similar to the ôMy Yahooö type
service, to allow the user access to his/her personal profile
and services from any web-enabled device.
7. The UE SHOULD be able to poll for the nearest Relay Proxy to
reduce data traffic and reduce the cost of network usage. Also
the UE MUST be able to change Relay service centers at any time
(preferably via a menu with the relay service centers listed).
8. The UE SHOULD be able to use the relay service centers list to
sequence the relay centers in a preferred position: which to
use first for outgoing calls and automatically move on to the
next in the list if it is busy or does not support the required
services.
9. Relay centers SHOULD be able to advertise the services they
have and update for new services, perhaps via a central
registration (voluntarily) or via dialing into an info number.
The UE should be able to dial automatically to such info
numbers. This would stimulate competition between relay
centers, which will lead to lower service prices and/or more
different kind of services.
10. The UE SHOULD be able to hide from the callee that a relay
center is being used. This means the user SHOULD be able to
place the call as if the UE is actually calling the callee
directly, while the relay center working transparently. This
requires the relay center to act like a proxy.
11. Relay centers SHOULD be able to act as an answering machine
and provide message services. The UE SHOULD have the capability
to retrieve messages (answering machine mode). The UE SHOULD
have a pre-configurable setting that automatically connects a
calling party to the relay center for answering machine service
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when the user does not want to receive incoming calls. This
happens transparently without extra handling of the caller.
Voice messages left for the UE MUST be interpreted at the relay
center into the format designated by the UE (email, IM, video
clip, etc.) and transmitted to the UE on demand or when the UE
registers. Note: This ôanswering serviceö would also be a
possible commercial service for non-Deaf users.
12. The UE MUST be able to distinguish non-relay calls from relay
calls and direct TTY calls, if this number is NOT listed in the
address book (which stores the number and options for direct UE
to UE calls such as TTY to TTY, which do not require a relay
center). A message will be sent to the originator of the call
(183 Deaf USER RELAY call only). Depending on technological
advances and the user's preferences, instead of the UE
returning a 183 message, the UE MAY rapidly connect to the
relay center and accept the call as if there is NO relay center
in between (STEALTH mode; invisible relay services for the
caller, in this way the user can conceal his/her hearing
status). This should be seen as a separate service and possibly
charged extra due the speed of accepting the call (minimal
delay on picking-up) and extra effort to be invisible to the
caller. Special hardware and software may be required for
computer run speech to text conversion (this may require
specialized relay centers). Note: this service can be used
selectively for certain callers, and other callers are just
notified by the 183 message.
13. The UE MUST be able to place calls transparently, the DP does
not have to call the relay center first and then tell the phone
number etc to call. It will be done automatically. A number
will first checked in the address book in case of direct calls
not requiring a relay center, if not, the UA will connect to
the relay center and call the callee automatically. Ordering
Pizza for example.
14. The UE SHOULD be able to place calls anonymously, a ôcloakö
option that prevents the relay service to receive the caller-ID
etc. In cloak mode, the UE sends a modified INVITE to the relay
service with a random caller-ID and a tag indicating that this
is an anonymous call. The relay center proxies MUST hide all
via and route-record headers so that the call cannot be traced.
The relay center MUST be required to make sure that there is no
trace from the center to the UE.
7. Security Considerations
Because an interpreter is generally required when a Deaf
individual has a conversation with a non-deaf individual, whether
in person or using a medium such as the telephone, interpreters
are privy to a great deal of private information. For this
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reason, both the Deaf and interpreter communities are vitally
interested in the ethics and professionalism of the interpreter.
Interpreters in the United States that are certified by the
organizations recognized by the Deaf Community, such as the
National Association of the Deaf (NAD[10]) and the Registry of
Interpreters for the Deaf (RID[11]), are required as part of their
certification to support the Codes of Ethics of their
organizations.
Hence these requirements:
All relay operators and other interpreters or organizations
involved in relaying calls SHALL be required to subscribe to a
generally accepted Code of Ethics for interpreters. As an example,
the Code of Ethics required for membership in RID is as follows:
ôThe Registry of Interpreters for the Deaf, Inc. has set
forth the following principles of ethical behavior to protect
and guide interpreters and transliterators and hearing and
deaf consumers. Underlying these principles is the desire to
insure for all the right to communicate.
ôThis Code of Ethics applies to all members of the Registry
of Interpreters for the Deaf, Inc. and to all certified non-
members.
1. Interpreters/transliterators shall keep all assignment-
related information strictly confidential.
2. Interpreters/transliterators shall render the message
faithfully, always conveying the content and spirit of the
speaker using language most readily understood by the
person(s) whom they serve.
3. Interpreters/transliterators shall not counsel, advise or
interject personal opinions.
4. Interpreters/transliterators shall accept assignments
using discretion with regard to skill, setting, and the
consumers involved.
5. Interpreters/transliterators shall request compensation
for services in a professional and judicious manner.
6. Interpreters/transliterators shall function in a manner
appropriate to the situation.
7. Interpreters/transliterators shall strive to further
knowledge and skills through participation in workshops,
professional meetings, interaction with professional
colleagues, and reading of current literature in the
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field.
Interpreters/transliterators, by virtue of membership or
certification by the RID, Inc., shall strive to maintain high
professional standards in compliance with the Code of Ethics.
This Code of Ethics is widely accepted and supported as a
standard within the American Deaf community and the American
community of interpreters. More information on RID can be
found from the organizationÆs web site, see reference [10].
In addition to the standards required for individual relay
operators, interpreters, and companies that provide relay
services, the actually transmissions MUST be secured. One option
for this could be IPSEC.
An extension to the requirement for ôcloakingö: relay
operators/interpreters MAY act on behalf of the user, at the
request of the user. For example, the user can ask the operator
to call a company to file a complaint. This requires
confidentially and an extension to the usual role of an
interpreter.
8. References and Footnotes
[1] Bradner, S., "The Internet Standards Process -- Revision 3", BCP
9, RFC 2026, October 1996.
[2] S. Bradner, "Key words for use in RFCs to indicate requirement
levels". Request for Comments 2119, Internet Engineering Task
Force. March 1997.
[3] TTY: an acronym for a text telephone device used by Deaf
individuals to communicate via telephone systems; commonly
referred to as a ôTDDö by the hearing community.
[4] M. Handley, H. Schulzrinne, E. Schooler, and J. Rosenberg, "SIP:
Session Initiation Protocol". Request for Comments 2543,
Internet Engineering Task Force, Mar. 1999.
[5] M. Handley and V. Jacobson. "SDP: Session Description Protocol."
Request for Comments 2327, Internet Engineering Task Force,
April 1998.
[6] "Culturally Deaf" individuals are people who have some degree of
hearing loss but consider themselves as Deaf, not "hearing
impaired". They tend to identify themselves as members of the
American Deaf Culture, a unique cultural minority in America.
See [8] for more details.
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[7] "Audiologically deaf" individuals are people who have some
degree of hearing loss but who tend to identify themselves as
"hearing impaired" and as members of the majority hearing
culture in America, not as part of Deaf Culture. See [8] for
more details.
[8] "American Sign Language": the natural manual language used by
the members of Deaf Culture in America. For a more in-depth
description of this language and its central role in the Deaf
Community in America, see the text "_American Sign Language: A
Teacher's Resource Text on Grammar and Culture_" by Charlotte
Baker-Shenk and Dennis Cokely. See also the suggested readings
listed in the Background section of this document.
[9] H. Schulzrinne and J. Rosenberg, "SIP caller preferences and
callee capabilities," Internet Draft, Internet Engineering Task
Force, July 2000. Work in progress.
[10] National Association of the Deaf. A national organization of,
for, and operated by Americans who are Deaf or deaf. Organized
in 1880, it is "the oldest and largest organization representing
people with disabilities in the United States. The NAD
safeguards the accessibility and civil rights of 28 million deaf
and hard of hearing Americans in a variety of areas including
education, employment, health care and social services, and
telecommunications. A private, non-profit 501(c)(3)
organization, the NAD is a dynamic federation of 51 state
association affiliates, sponsoring and organizational
affiliates, and direct members." See "www.nad.org" for more
information on this organization.
[11] Registry of Interpreters for the Deaf (RID). A national,
professional organization of interpreters and transliterators
for the Deaf in America. "The philosophy of RID is that
excellence in the delivery of interpretation and transliteration
services among people who are Deaf, or Hard of Hearing, and
people who are hearing, will ensure effective communication. As
the professional association for interpreters and
transliterators, the RID serves as an essential arena for its
members in their pursuit of excellence. It is the mission of
the Registry of Interpreters for the Deaf, Inc., to provide
international, national, regional, state, and local forums and
an organizational structure for the continued growth and
development of the professions of interpretation and
transliteration of American Sign Language and English." See
"www.rid.org" for detailed information on this organization.
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10 Acknowledgments
The authors would like to acknowledge Jonathan Rosenberg, et al,
for the initial draft "SIP Enabled Services to Support the Hearing
Impaired" [Internet Draft, Internet Engineering Task Force, July
13, 2000. Work in progress], which began the analysis that has
led to this document.
The authors would also like to thank the following Deaf
individuals, professional interpreters, and others who have
contributed to the development of this document:
Mr. Charles Estes, WCom
Ms. Helene Cohen-Gilbert, Coordinator, Collin County Community
College: Interpreter Preparation Program û Deaf.
Mr. Grant Laird,
Mr. Brenden Gilbert
11. Author's Addresses
Cathy Gearhart
Ericsson, Inc.
P.O. Box 833675, M/S L-04
Richardson, TX 75083-3875
email: cathy.gearhart@ericsson.com
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
Henry Sinnreich
MCI Worldcom
400 International Parkway
Richardson, Texas 75081
email:henry.sinnreich@wcom.com
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