This report is also available as an Acrobat file.
Note: The Cray Communications Pocket Book Collection provided several of these
explanations and definitions.
Adaptive DPCM (where DCPM is differential
PCM, transmitting value differences, and
adaptive means dynamically adjusting
parameters to the data stream).
Asynchronous Transfer Mode networks (based
on packet switching). A mode of data transfer
in which units of data are not time-related to
Broadband ISDN. A communication channel
having a bandwidth greater than a voice-grade
channel 1 and therefore capable of higher-
speed data transmission.
Charged Couple Device camera.
International Radio Consultative Committee.
International Telegraph and Telephone
Consultative Committee. A standards body
concentrating on definition of European
Code Excited Linear Prediction. The most
common vocoder technology in use today,
which uses "codebooks" to quantise the input
signal. The CELP algorithm provides excellent
speech quality and is well suited for tele-
Common source Intermediate Format.
An item of equipment containing an encoder
and a decoder. A device which performs the
dual function of encoding two-way analogue
data and two-way digital data into analogue
Defense Advanced Research Project Agency.
Dynamic Memory Addressing.
Digital Signal Processor.
Digital Video Interactive (Trade Mark of the
European Teleconferencing Federation.
A LAN transmission network utilising a bus
structure, first produced by Xerox in the USA,
later adopted by both DEC and Intel as well.
This was later adapted to create the IEEE 802.3
and ISO 8802-3 standards.
European Telecommunications Standards
Institute. Membership is open and there are
currently 135 member organisations including
national administrations, public network
operators, manufacturers, users and research
Fibre Distributed Data Interface. A token
passing ring network specification developed
by ANSI, implementing dual optical fibre
rings. The network operates at 100Mbps and
can be up to 100 kilometres in length.
Frames per second.
File Transfer Protocol. A protocol from the
Internet Protocol Suite which provides transfer
of files between two dissimilar machines.
A series of audio visual communications
recommendations which were ratified by the
CCITT in December 1990. The aim of the
series, which applies to audio visual
communications over 56/64 Kbps to 2.048
Mbps channels, is to ensure videoconferencing
systems and video terminals will interconnect
across any network. H.320 is an umbrella
standard encompassing a series of
- H.221 (frame structure for a 64-1920Kbps channel);
- H.230 (frame synchronous control and indication signals);
- H.242 (systems for establishing communications between audio visual terminals using digital channels up to 2 Mbps);
- H.261 (visual coding for transmission over 56/64-2048 Kbps digital channels);
- G.711 (3.5 kHz narrowband audio specification for 48-64 Kbps channels);
- G.722 (7 kHz wideband audio specification for 48-64 Kbps channels);
- G.728 (3.5 kHz audio specification for 16 Kbps channels).
High definition TV (e.g. 1125 or 1250 lines).
HyperText Transfer Protocol.
Institute of Electrical and Electronic Engineers.
An American Institute responsible for
developing and publishing many
Internet Engineering Task Force. Part of the
organisation that develops Internet standards.
A vast community of computers, distributed
around the world, which share common
Integrated Services Digital Network. Basically
the existing telephone network using existing
but upgraded switches and wiring, but all
digital, giving a bandwidth for a basic call of
64 kbps. This increased bandwidth allows the
transmission of high fidelity compressed audio,
as well as the potential for video
International Standards Organisation.
Joint Academic NETwork.
Joint Broadcasting Information Group.
Generates standards for binary image
compression (e.g. faxes).
Joint Information Systems Committee (of the
Higher Education Funding Councils of
England, Scotland and Wales). Responsible for
Joint Network Team. Forerunner of UKERNA.
Joint Photographic Experts Group. Generates
standards for still image compression.
Local Area Network. A system for
intercommunication between computer
terminals, PCs and related equipment operating
within the same general area.
London Interactive Video Network. A hybrid
network combining analogue and digital
communications, with gateways to ISDN,
SuperJANET, Internet and satellite.
Metropolitan Area Network. A geographically
extended high-speed LAN designed to
interconnect users within a city or metropolitan
Multicast Backbone. A virtual network that has
been in existence since early 1992. Originated
from an effort to multicast audio and video
from meetings of the IETF. Shares the same
physical media as the Internet. MBONE today
is used by several hundred researchers for
developing protocols and applications for group
communication. It is a co-operative, volunteer
Multipoint Conferencing Unit.
Multimedia and Hypermedia information
coding Experts Group. Generates standards for
multimedia data (such as integrating stills,
video, audio, text, etc.).
Multimedia Integrated Conferencing for
European Researchers. Co-ordinated by
University College London, this project aims to
provide a multi-way integrated conferencing
service between a number of European pilot
sites, and link them to the appropriate
communities in the US.
Moving Picture coding Experts Group.
Generates standards for digital video and audio
Network Basic Input/Output System. A
network communication system operating on
MS/DOS PC networks.
(US) National Television System Committee -
Office Document Architecture. Defines the
structure of complex documents for interchange
between systems in an OSI environment. It also
provides for the creation, change, consolidation
and management of documents using screens or
printers as necessary for input and output (ISO
Open Systems Intercoynnection. The term
defined by the International Standards
Organisation as a basis for standards to enable
different vendor systems to interwork without
Open Shortest Path First.
Phase Altering Line. The TV standard in much
of Europe which uses YUV colour space (i.e. Y
luminance, 1.3 MHz chrominance components
Private Branch Exchange.
Pulse Code Modulation. An encoding
technique for digitising analogue voice signals
(used, for example, with CD audio).
Plesiochronous Digital Hierarchy.
Public Network Operator
Plain Old Telephone System.
Public Switched Telephone Network.
Quarter Common source Intermediate Format.
Produced by Apple, QuickTime is a set of
protocols that allow a Mac or a PC running
Windows to use a single interface to
create/display/manipulate movies that contain
digitised video, sound, text, etc.
Resource Interchange File Format.
Réseaux IP Européens. Co-ordinator of the
Internet community in Europe. Operational
since 1989. A RIPE Network Co-ordination
Centre in The Netherlands provides Internet
management functions, network software and
Real Time Protocol. A transport protocol for
audio/video data that is being developed by the
Audio/Video Transport working group of the
Internet Engineering Task Force.
Synchronous Digital Hierarchy.
Standard Generalised Mark-up Language
(mark-up metalanguage - ISO 8879).
Switched Multimegabit Data Service.
A national high performance network
supporting UK education and research. It
currently provides three services: a high
performance IP service to all connected sites,
an ATM service to a sub-set of the connected
sites and a video network to the ATM sites.
High resolution VGA often 800X600 pixels
and 256 colours with faster scanning rate.
Separate-video (also known as Y/C) in which
the luminance and chrominance information of
a video signal are carried on separate wires.
A digital communications path operating at
Transmission Control Protocol/Internet
Protocol. Two main network communication
protocols, part of the Internet Protocol Suite.
Technology in Learning and Teaching
Programme (run through UCOSDA).
A LAN transmission network utilising a ring
structure. The most common form is IBM
Token Ring. This network type is detailed by
the IEEE 802.5 and ISO 8802-5 standards.
Telecommunications Users Association.
User Datagram Protocol.
UK Education and Research Networking
Association. A company that has been set up to
manage the networking programme for the UK
higher education and research community.
Variable rate ADPCM compression.
Video Electronics Standards Association.
Virtual Graphics Adapter. Standard 640X480
resolution PC monitor configuration.
Wide Area Network. A network which uses
public or private circuits to link terminals, PCs
and computers over long distances that also
often allows some user choice in destination.
Following the implementation of routers,
bridges and gateways, many LANs are
becoming WANs, but more typically networks
such as X.25 are classed as WANs.
World Wide Web.
Virtual Environments Visualisation