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A Vision for Relay Services and Interoperability. Christian Vogler, PhD Director, Technology Access Program Gallaudet University. P urpose of this talk. What this talk is about

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A vision for relay services and interoperability

A Vision for Relay Services and Interoperability

Christian Vogler, PhD

Director, Technology Access Program

Gallaudet University

P urpose of this talk
Purpose of this talk

  • What this talk is about

    • A vision for extending the principle of functional equivalence to global telecommunications and new forms of telecommunications

    • Technologies and standards issues

  • What this talk is not about

    • Policies needed to make this vision happen

    • Legal frameworks

    • Funding

Functional equivalence
Functional Equivalence

  • An attempt at a definition:

    Can deaf* people use telecommunication services in the same unrestricted manner and at the same costs as hearing people?

    * “deaf” is meant to include deaf-blind, hard of hearing, and people with speech disabilities, as well here

Call scenarios
Call Scenarios

  • What do hearing people take for granted in telecommunications?

Call scenario same country
Call Scenario: Same Country

Alice (h)

Bob (h)

Call scenario international
Call Scenario: International

Carl (h)

Alice (h)

Call scenario roaming travel
Call Scenario: Roaming/Travel

Carl (h)

Alice (h)

Call scenarios1
Call Scenarios

  • Let’s see what deaf people can do

    • Need to consider both relay and point-to-point

    • Why: principle of familiarity – should be able to use common equipment for everyday and emergency communications

  • Remember: this is about technology

    • Some countries have additional policy restrictions

Deaf call scenario same country
Deaf Call Scenario: Same Country

Dan (d)

Alice (h)



TRS = Telecommunications Relay System – here: all forms of relay

*Assumes integration of deaf user’s equipment into telephone numbering system, a.k.a Ten-Digit-Numbering. (currently only US, and partially UK)

Deaf call scenario same country1
Deaf Call Scenario: Same Country

Dan (d)

Emily (d)

Point-to-point: Works mostly, but not uniformly (and some countries better than others)

Deaf call scenario international i
Deaf Call Scenario: International (I)

Carl (h)


Dan (d)


Call is routed through relay in Dan’s country, in Dan’s language

*Assumes integration of deaf user’s equipment into telephone numbering system

Deaf call scenario international ii
Deaf Call Scenario: International (II)

Carl (h)


Dan (d)


Call is routed through relay in Carl’s country, in Carl’s language

*Does not work with integration into telephone numbering system

Deaf call scenario international iii
Deaf Call Scenario: International (III)

Frank (d)

Emily (d)

Point-to-point: Does not work with same equipment as used for relay calls

Call scenario roaming travel1
Call Scenario: Roaming/Travel

Carl (h)

Emily (d)


Call is routed through relay in Emily’s country, in Emily’s language

Works only if Emily can use her own equipment (and connection is not impeded or impaired). Does not work if Emily borrows equipment in Carl’s country.

What is missing
What is Missing?

  • Voice calls (hearing side) are interoperable

    • Global standards for landline, mobile, and interconnected VoIP

  • Relay calls (deaf side) are not interoperable

    • Codecs and protocols (H.263, H.264, H.323, SIP, proprietary, …)

    • Call setup (i.e. how do I dial the call?)

    • Lack of interoperability with mainstream VoIP equipment (here: also includes video and text over IP)

Codecs and protocols
Codecs and protocols

  • Need standards for codecs and protocols:

    • Video, audio, text, images

    • Must meet functional performance requirements for communication

      • E.g. sign language communication requires minimal frame rate, resolution

      • Recovery from network problems may be different from current practice in mainstream VoIP

    • Must work across environments (e.g. Internet, IMS, and next-generation emergency)

    • Should be compatible with mainstream equipment (“may I borrow your videophone?”)

Call setup
Call Setup

  • Need standards for call setup:

    • Connecting to relay provider and point to point

    • Integration into the mainstream telecommunications network (i.e., 10-digit numbering or equivalent)

      • Related policy question: who assigns – relay or telecommunications carrier?

    • Passing hearing party’s number to relay service (i.e. I can dial and don’t have to fingerspell it)

    • All this must work when roaming

Supplemental services
Supplemental Services

  • Standards for interacting with supplemental services:

    • Voicemail, Videomail (i.e., can deaf caller leave a message, can hearing caller leave a message, point-to-point messages?)

    • Call alerting (i.e. how are deaf people notified of an incoming call?)

    • Others?

Looking ahead teleconferencing
Looking Ahead: Teleconferencing

This is what currently works:


Audio bridge

Alice (h)

Dan (d)


Bob (h)

Emily (d)


Frank (d)

Carl (h)

Looking ahead teleconferencing1
Looking Ahead: Teleconferencing

  • Not functionally equivalent

    • Hearing parties can hear one another

    • Deaf parties cannot see one another

    • Double translation – from Dan to TRS A, and from TRS B/C to Emily/Frank

      • Degrades accuracy and quality

      • Introduces additional unacceptable lag

  • Wasteful

    • Availability of relay operators already cannot meet demand

    • Separate interpreters need to be paid, even if they use the same language and communication modality

Looking ahead teleconferencing2
Looking Ahead: Teleconferencing

This is what we need:

Dan (d)

Multimedia bridge

Alice (h)

Emily (d)

Bob (h)

Frank (d)

Carl (h)


Looking ahead teleconferencing3
Looking ahead: Teleconferencing

  • Relay services need to track emerging standards for interoperable teleconferencing systems

  • Note: In the US, interoperable teleconferencing systems are required by law and recent FCC rules to be accessible under the “Advanced Communication Services” provision of the 21st Century Communications and Video Accessibility Act

Areas that need attention
Areas that Need Attention

  • Next-generation emergency services

    • E.g. REACH 112, NG-9-1-1

  • The switch to mobile telephony

    • On LTE calls will be IP-based

    • Unclear yet how relay services will interact with the IP Multimedia Subsystem (IMS)

NENA motto:

“Any device, anytime, anywhere”

Let’s make this happen for relay services, too!


The contents of this presentation were developed with funding from the National Institute on Disability and Rehabilitation Research, U.S. Department of Education, grant number H133E090001 (RERC on Telecommunications Access). However, those contents do not necessarily represent the policy of the Department of Education, and you should not assume endorsement by the Federal Government.


Email: [email protected]: http://tap.gallaudet.edu/

Related work

Vogler et al. Video Relay Service Practices and Policies around the World. To appear in AEGIS workshop, Nov 28-30, 2011.

Functional performance characteristics

  • ITU-T H-series Recommendations – Supplement 1, 05/99

  • FCC filing in CG Docket 10-51. Online: http://fjallfoss.fcc.gov/ecfs/comment/view?id=6016375091