Words to Know for Videoconferencing Success

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A

analog - audio/video signals currently used in broadcasting 

B

bandwidth - A measure of the amount of data that can fit on a network - videoconferencing requires large high capacity bandwidth.  

bit - binary digit - smallest unit of information - 1 or 0

bps - bits per second

bridge - A networking device that connects several video sites into one videoconference

broadband - A high capacity communications circuit or path - broadband is required for effective videoconferencing

camera - Video device that captures pictures to relay to far end site 

codec - coder/decoder -  A piece of hardware or software that codes and compresses the outgoing and decodes and decompresses the incoming audio and video signals.   

compressed video - Video/audio information is squeezed into a fraction of its former bandwidth by a codec with diminished picture and sound quality.  This compact form can be transmitted over smaller carriers.
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Glossary Quick Links:

• Digital Bridges 
• PacBell
• Videoconferencing Cookbook
• Videoconferencing Glossary
• Wire One

• Behavior Guidelines  
• Document Sharing  
• Glossary
• Hardware Tutorial  
• Planning  
• Resource Sites    
• Set-up
• Software Tutorial 
• Student Accommodation 
• Timeline for Videoconferences  

D

desktop videoconferencing - Videoconferencing on a personal computer with a small camera mounted on top of a monitor and microphone attachment.  Computer software allows transmission of video, audio, and document sharing.  This kind of videoconferencing is designed for one-on-one interaction.  

document sharing - Software system that allows participants to display, view, and edit the same computer document

E

echo suppression or cancellation - A method of eliminating echo in a videoconferencing room - general software adjustments by far end to eliminate the audio echo coming back from the other end of the circuit

ELMO - Desktop camera used for close-up or artifacts or specimens and/or document display - manufactured by Electric Light Machine Organization

F

frame rate - Measure of the frequency of the display of video frames on a monitor.  Full motion video is 30 frames per second and motion is continuous.  High bandwidth is required to broadcast at 30 frames per second. Many videoconferencing sessions are broadcast at 15 frames per second with slight delays or jerkiness apparent. 

full duplex - Sending data in both directions at the same time - requiring high bandwidth.  The result is higher quality and more natural audio and video. Half duplex means that data can only flow in one direction at a time causing delays.

G

gateway - Provides a link or connection between the H.323 system and other video conferencing systems such as the H320 system.  The gateway is managed by a gatekeeper who controls access to the network, directs and manages the bandwidth, helps with address resolution and provides overall management of the gateway.

H

H.320 and H.323 - Video compression standards for videoconferencing.  H.320 is appropriate for ISDN and fractional T1 lines.  H.323 is used for videoconferencing over networks that do not guarantee bandwidth, such as the Internet.  A gateway is needed to connect H.320 networks with H.323 networks for videoconferencing.

Half duplex - Data can only flow in one direction at a time 

I

IP - Internet Protocol - the basic language of the Internet

ISDN - Integrated Services Digital Network - digital telecommunications standard with high bandwidth that accommodates voice, video, and text.  (A gateway or multipoint control unit (MCU) is needed to bring ISDN and H.320 or H.323 conferences together.  The gatekeeper provides the service to make the needed bridge.)

M

multipoint conference - A videoconference with more than two sites.  The sites are connected using a multipoint control unit.  Multiple windows are used to display the sites participating in the multi-conference.

multipoint control unit - (MCU) A device for implementing multipoint conferences.

P

point to point videoconference - A videoconference limited to two sites.

R

real time - A live presentation where the transmission takes place right away without perceptible delay.

router - A device that connects networks  

S

streaming media - Receiving audio or video over a network as needed instead of downloading the entire file before viewing.  The stream is buffered, sending a portion of the data ahead, to allow for seamless viewing of the stream.  

T

teleconferencing - A general term for videoconferencing, audio conferencing, or data exchange between two people who are geographically distant from each other.

T1 - A higher speed telephone circuit for dedicated connections capable of 1,544,000 bits/second.

touch panel - A touch sensitive display device for controlling equipment

V

videoconferencing - A conference during which participants use a desktop computer and/or specialized video conferencing equipment to send and receive video, audio, and text in real time via the Internet.

References/Site Map

conniepepper@cableone.net
Last updated 03/31/03