Glossary

Bandwidth

The amount of data that is actually being sent down the telephone/isdn/network line. This is measured in KBPS

Bridge/External Bridge

See MCU

Camera Presets

Allows predefined camera angles to be programmed into a videoconferencing system

CODEC

Coder Decoder for video signals. Converts analogue video signals to digital signals for transmission over digital circuits, and then converts the digital signals back to analogue signals for display

Continuous Presence

Conference where multiple sites are seen on the screen simultaneously for the entire conference

Document camera

A specialised camera for taking pictures of still images (pictures, graphics, text pages) to be sent as part of a videoconference

Echo Cancellation

Process of eliminating acoustic echo in a videoconferening room. This is a critical component. If echo is not suppressed, the speaker hears their own audio coming back from the far site after a small time delay

H.239 standard

A protocol for document sharing, system dependent and not available from all videoconferencing units

H.323 standard

A video compression standard that allows a wide variety of systems to communicate

Interactive Whiteboard (IWB)

An interactive whiteboard is a device that interprets a projected two dimensional surface that interacts with a computer's desktop. The software mimics the computer's mouse and keyboard. Used to send whiteboard interactions as part of a videoconference

IP (Internet Protocol)

The computer networking protocol used on the internet

IP address

Internet Protocol address - a computer network address

ISDN

Integrated Services Digital Network - telephone network system designed to allow digital transmission of voice and data over ordinary telephone copper wires

KBPS

Kilobytes per second

KLDC

Kwong Lee Dow Centre

Lecture mode

A conference where a single site (the presenter) is viewed by all other sites. The presenter sees the other sites in Continuous Presence mode

MCU

Multiple Control Unit - (Bridge) a unit that supports videoconferencing with multiple users at the same time. In videoconferencing, a bridge connects three or more sites so that they can simultaneously pass data, voice or video

People + Content

Polycom proprietry presentation protocol

Picture-in Picture (PIP)

A small window on the monitor that displays the image from a video source superimposed on the image being displayed on the full screen

Roll Call

Videoconference administrator conducts a roll call of all connected sites before proceeding with the conference

Transmission Speed

The speed at which the hardware used for conference connects 128Kbps, 256Kbps, 384Kbps

Videoconference

Communication across a network with video and audio contact that may also include data exchange

Voice Switched

A conference where the view automatically switches to the site that is talking (or loudest)