Total Conversation

In telecommunication, Total Conversation encompasses the use of a Total Conversation service which is defined in ITU-T recommendation F.703^[1] as “An audiovisual conversation service providing bidirectional symmetric real-time transfer of motion video, text and voice between users in two or more locations”.

In simple terms, a Total Conversation^[2] service allows people in two or more locations to:-

see each other;
hear each other; and
send text to each other,
mixing or not those different modes,

all in real-time.

1 Application
2 Total Conversation and Universal Design
3 Implementation of the concept
4 Conversation Totale and IP Multimedia Subsystem
5 References
6 External links

Application

Conference call for businesses will need to use audio and text and may use video to share documents.
Deaf people using sign language would be more than satisfied to call each other with video.
Deaf people using sign language can also call, and be called by hearing people using Video Relay Service.
Hard of hearing people to call each other directly with voice and text and even video for lip-reading.
Hard of hearing and deaf people who do not use sign language (orally and late deafened) need to access a Text Relay Service with an audio plus text call in order to be able to speak but also to receive captions.
Text-only call is the only way to make a call for deaf-blind user using braille display.
Text call mixed to audio feedback is the only way to make a call for speech disabled user
video, text and audio combined call is the only suitable way to make a call for cognitive disabled user.
Text only call might be convenient in situation when audio communication is not permitted, available or dangerous (noisy situation, low bandwidth).
Support and hot line might be contacted with an audio-only call and add a video stream if the user needs to show the actual issue he or she is facing on a device.

Total Conversation and Universal Design

Total Conversation is a straightforward application of Universal Design principles applied to telecommunication field. This concept brings communication services to the broadest range of population including deaf people, hard or hearing people but also people who have speech impairment, people with cognitive impairement, elderly people, children, and also ... regular users. It is an enhancement of call services that provides a better experience to all. Total Conversation uses video, text and audio. These media can be combined or not depending on the type of profile used : many user profiles have to be taken into account. Such methodology is named Universal Design.

Implementation of the concept

Available implementations

A number of European companies including 4CTel, Aupix, IVèS^[3] and Omnitor^[4] but also Orange Labs produced implementations. These are mostly used to provide user-to-user calls and Relay Services for deaf and Hard of hearing people.

The REACH112 European Project

The REACH112^[5] include most of these companies mentioned above and several European companies offering services to deaf people as well as Emergency services. It is named after the "112" number which is the European emergency number like the 911 in the USA. The purpose of the project is to establish pilots in five countries in order to test Total Conversation on the field with several thousands users and for three usages:

European wide person to person calls
Total Conversation Relay Services for deaf people
Total Conversation used for emergency calls.

One of the important outcome of the project is the delivery of a technical document describing how Total Conversation should be implemented. This is done in the deliverable D3.2 Platform Specification.^[6] This document targets the videophone manufacturers but also the electronic communication regulators and people working on next generation emergency services (NG 112 in Europe)

Purpose of these specifications

These specifications describe:

An interconnection interface between Total Conversation Service Providers including Relay Services.
A user to network interface for videophone manufacturers.
A call interface for Next Generation Emergency Services in Europe Europe^[7] including an information sharing capability.

Technical protocols used by Total Conversation are

Session Initiation Protocol for call signalling,
T.140^[8] with an RFC 4103.^[9] for Real-Time Text^[10] (RTT)
Video codecs H.263 and preferably H.264.
Audio codec ITU-T G.711 and other as commonly used in VoIP calls.

(* Use of Common Alerting Protocol may be also considered to share information with Emergency Services.)

Total Conversation defines three basic services

seamless multimedia person to person calls including the ability to call regular telephone users.
the ability to invoke a relay service by deaf or hard of hearing persons,
the ability to call emergency services in Total Conversation mode.

Conversation Totale and IP Multimedia Subsystem

Total Conversation basically provides a multi-media call services with specific media enabled. The currently most common implementation environment is native SIP as described above.

Total Comnversation can also be implemented in other call control environments. One such environment is IP Multimedia Subsystem (IMS) in its IMS Multimedia Telephony service.

Firstly, Total Conversation can be defined as a pragmatic selection of existing standards related to (Session Initiation Protocol with the selection of audio, video and text codecs. It is a private initiative of services provider and technology vendors seeking interoperability in the broadtest sense.

Secondly, this can apply to existing and deployed SIP platform rather than future or next generation networks.

Thirdly, IMS is much more ambitious and define a whole architecture, including all internal interfaces and billing and physical infrastructure. Theses standards are more suitable for large telecommunication operators and their equipment vendors. This complexity has consequences:

Very little UMTS release 5 networks fully supporting IMS are in production^[11]
Multimedia call services defined by MMTEL are not translated^[12] in actual usable services on the market. An industry led initiative called Rich Communication Suite^[13] finally plans to do this .. when IMS will be rolled out in the networks.
Rolling out a Native SIP Total Conversation services needs investments that are very reduced compared to the IMS equivalent. However, the implementations in both environments are close enough that interoperability between the two is an easy task.