Prognosemetoder – en oversikt - Telenor

Table 2 ITU Recommendations for conference control
ID Name Status
T. 120 Introduction to the T series audiovisual
recommendations
Under study
T. 121 Audio Graphics Conferencing (AGC) Under study
T. 122 Multipoint Communication Service for audio
graphic and audio visual conferencing
Approved
T. 123 Protocol stacks for audiographic and
audiovisual teleconference applications
Approved
T. 124 Generic conference control for
audiovisual services
Under study
T. 125 Multipoint communication service Approved by
protocol specification SG 8 to be sent
on ballot
192
audiovisual area that will be important for multimedia applications.
The following standards have been approved:
Other standards covering the audio aspects, and applications
such as
- audiographic conferencing in the ISDN
- videoconferencing in the ISDN
- Multipoint Control Units (MCU)
are under study.
For multimedia standardisation there is a need to identify a
common platform. The ITU-T T.120 series recommendations
could be this platform because they take into consideration both
audiovisual applications and provide protocols for telematic
applications and data communication. An introduction to these
recommendations can be found in the ITU-T part of this presentation.
This topic will be on the agenda for the next meetings of
the ETSI committees involved.
Another topic of great commercial interest is standards for regulatory
purposes. Directive 91/263/EEC regulate the rules for
type approval of telecommunications terminal equipment in
Europe. The type approval is based on Common Technical Regulations
(CTR). ETSI is responsible for providing the technical
base for CTRs, TBRs (Technical Base for Regulations). TBR 8
(Terminal requirements for ISDN 3,1 kHz telephony terminals)
has been on Public Enquiry, and is now ready for national vote.
Norwegian Telecom Research has provided the rapporteur for
TBR 8.
The access TBRs for ISDN Basic Rate Interface (TBR 3) and
ISDN Primary Rate Interface (TBR 4) will be ready for submission
on Public Enquiry by end of March 1994. The European
Commission is considering in interim arrangement until these
TBRs are approved.
There are three STCs reporting to TC HF. STC HF1 is working
on Human Factor issues in general, while STC HF2 is working
on issues related to people with special needs. STC HF3 is
working on usability evaluation.
Most of the results of TC HF are technical reports or guidelines.
Reports on human factor aspects of Multimedia telecommunication
(DTR/HF 01016), and on end-user procedures for ISDN
videotelephony (DTR/HF 01018) are under preparation. A draft
standard on pictograms for videotelephony (prETS 300 375) is
on Public Enquiry.
ITU-T
Within ITU-T, several Study Groups are working on terminal
equipment and user aspects. These are:
- SG 1 (Service definitions) on some user aspects (Human Factors)
- SG 8 (Terminal for telematic services) on terminals and protocols
for telematic services
- SG 12 (End-to-end transmission performance of networks
and terminals) on speech transmission characteristics and
quality aspects moving image communication
- SG 14 (Modems and transmission techniques for data, telegraph
and telematic services)
- SG 15 (Transmission systems and equipment) on system
aspects/terminals for audiovisual communication.
SG 8 is probably the most important study group in ITU-T for
standardisation of terminals and applications. One important
activity is the work on a set of recommendations for conference
control (T.120 series of recommendations). The work covers
both point-to-point conferences and multipoint conferences.
These recommendations are:
The structure of this set of recommendations is as shown in Figure
1.
The following application recommendations are planned so far:
- T.SI Still image for the conference (JPEG)
- T.AVC High Level Audio and Video Control
- T.BWC Bandwidth Arbritation and Control
- T.TDC Transparent User Data Channel
- T.CFAX Multipoint Facsimile for AVC and AGC3 - T.RESV Reservations for AVC and AGC
- T.PRO Application Profiles for AVC and AGC
- T.CBFT Multipoint Binary File Transfer.
EURESCOM
The owners of EURESCOM are the Public Network Operators
in Europe. It is therefore logical that the main activities of
EURESCOM are on networks. However, one of the study areas
of EURESCOM is Services. Terminal equipment is not
addressed, but user aspects are considered in some of the projects.
3 AVC and AGC – Audiovisual Conference and Audiographic
Conference.