International Telecommunication Union
Total Conversation through ITU-T Standards:
Sign, Type, and Speak – You Decide
Paul E. Jones
Cisco Systems, Inc.
Plenary Session on ITU-T Standards
15th Biennial TDI International Conference –
Las Vegas, Nevada, USA
In the beginning, communication devices for the deaf opened
a whole new world for the users of those devices.
They enabled people to communicate in ways that were never
possible before.
Friends and family were able to carry on conversations over
long distances, helping to maintain and even strengthen those
relationships.
Without question, the introduction of the telecommunication
devices for the deaf enriched everyone's lives.
But times change…
And so do the modes of communication!
ITU-T
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
3
ITU-T
It’s All About
Total Conversation
o The ITU-T is working on standards that
bring about the convergence of
• Voice telephony
• Video telephony
• Text telephony
o These standards aim to enable what it
calls “Total Conversation”
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
4
Defining the Multimedia Service
ITU-T
o The ITU-T defined a series of service
specifications and included text and
video as components of the multimedia
services (F.700 and F.703)
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
5
Popular Multimedia Systems
ITU-T
o H.323 – Multimedia communication over
packet-switched networks (Internet)
o SIP – Session Initiation Protocol
(Internet) (IETF)
o H.320 - Multimedia communication over
ISDN
o H.324 – Multimedia communication over
low bit-rate links (phone lines and
mobile phones)
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
6
ITU-T
Problems with These Systems
Identified
o Multimedia systems had largely focused
only on voice and video
o There was a lack of support for text (or
at least acceptable text)
o Video support often did not take into
consideration the needs of the deaf
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
7
More Standards
ITU-T
o H Series Supplement 1 – Raised
awareness about sign language and lip
reading as it relates to video quality
o T.140 – Standard to allow Unicode for
textual conversation
• IETF RFC 2793 defines the transport of
T.140 over IP networks
• Used by both H.323 and SIP systems
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
8
Integration
ITU-T
o During the 1997 – 2000 timeframe, the
ITU-T worked to add support for realtime text communication to the popular
multimedia systems
o Acceptable video support was more of
an educational exercise… and the ITU-T
has made an effort to educate!
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
9
…But Still Segregated
ITU-T
o The video conferencing systems in use
today are:
• Largely used between two parties who
have the same equipment
• Not “tied into” the larger public
communications networks
o Further integration is required
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
10
The VoIP Revolution
ITU-T
o Since the late 1990s, the
communications industry has been
heavily focused on “voice over IP” or
“VoIP”
o The basic idea is to simply use the
Internet Protocol (IP) to carry voice,
video, and data communications (sounds
simple enough, huh?)
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
11
The VoIP Revolution (cont)
ITU-T
o VoIP is still in its infancy, as compared
to the mature public switched
telephone network (PSTN)
o Even so, a large number of telephone
calls are carried over IP networks today
o Unfortunately, multimedia
communication services (the video and
textual components) have been slower
to “take off”
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
12
ITU-T
Bridging Two PSTN Networks
over an IP Network
GK
GK
“Directory” Gatekeepers
GK
GK
GK
Service Provider IP
Core Network
H.323 PSTN Gateways
H.248 PSTN Gateways
MGC
MGC
GK
GK
14-16 July 2003
“Text over IP” – V.toip
Scheduled for approval in January 2004
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
13
ToIP Objectives
ITU-T
o Allow for character-by-character text communication
o Allow for simultaneous two-way conversation, along
with voice and video (inherent limitations of the PSTN
an obstacle)
o Standardize on an international character set
(Unicode)
o Support all standard TTY device types defined in ITU-T
V.18
o Enable different device types to communicate through
each other by using the gateways as “interworking”
devices (see next slide)
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
14
ITU-T
Interworking TTY Types
through the use of T.140
IP Network
Baudot Device
V.21 Device
T.140 bridges the gap
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
15
ITU-T
Building Bridges to the
Enterprise and Residence
H.248 PSTN Gateways
“Directory” Gatekeepers
MGC
MGC
GK
GK
GK
Residence
GK
GK
Service Provider IP
Core Network
GK
GK
GK
GK
Enterprise
H.323 PSTN Gateways
14-16 July 2003
Audio and Video Terminals and TTYs
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
16
Ultimate Goals
ITU-T
o To allow any device to support the
o
o
o
o
14-16 July 2003
transmission of video and/or text signals
To allow a user on a PC connected to an IP
network to chat with a user on a legacy PSTN
TTY device
To improve communications with the
widespread adoption of video
To allow a user with a wireless PDA to
communicate with anybody in the world
To not require special tools for
communications
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
17
ITU-T Standards…
ITU-T
Enable Video, Text, and Voice Communications.
So you can Sign, Type, or Speak.
You Decide!
14-16 July 2003
15th Biennial TDI International Conference – Las Vegas, Nevada, USA
18