Videoconferencing Glossary

Analog - An analog signal is one that uses electrical transmission methods to duplicate the original waveform. Voice and video sources(microphones, cameras) produce analog information; electronic equipment produces digital information. Analog networks are subject to interference, relatively low in reproduction quality, and not able to handle large quantities of data. Analog networks are rapidly being replaced by digital networks.

ATM - Asynchronous Transfer Mode. ATM provides a single network interface for audio, video, image, and text with sufficient flexibility for handling these different media types. The ATM transport technique uses a multiplexing scheme in which data are divided up into small but fixed-size units called cells. Each cell contains a 48-byte information field and five-bytes of header information for a total cell size of 53-bytes. Although it is a packet switching technique, ATM can achieve the integration of all types of traffic.

Classroom Technician - Person/persons designated to be in the IVN classroom during an event to monitor details in technical operation.

CODEC (Coder-Decoder) - Device used to convert analog signals to digital signals for transmission and reconvert signals upon reception at the remote site while allowing for the signal to be compressed for less expensive transmission.

Compressed Video - Video signals are downsized to allow travel along a smaller carrier. Some information is sacrificed in the process, which may result in diminished picture and sound quality.

Desktop Video - The merger of video, telephone, and computer technologies for the purpose of delivering multimedia information and telecommunication capabilities at the individual computer workstation.
Desktop Video - The merger of video, telephone, and computer technologies for the purpose of delivering multimedia information and telecommunication capabilities at the individual computer workstation.

DS-0 - Digital Service, level 0. Consists of 64,000 bps. A normal, uncompressed telephone call uses a DS-0 or 64,000 bps.

DS-1 - Digital Service, level 1. Consists of 1.544 Mbps in North America and 2.048 Mbps elsewhere. Also called T-1. Equivalent to twenty-four DS-0 channels.

DS-3 - Digital Service, level 3. Consists of 44.736 Mbps or commonly know as 45 Mbps. Equivalent to twenty-eight T-1 channels. Also called T-3.

Digital signals - A data signal transmitted using discrete steps in voltage rather than frequency, as in an analog signal.
Distance Education - Conveying knowledge from a distance. The organizational framework and process of providing instruction at a distance. Distance education takes place when a teacher and student(s) are physically separated, and technology such that voice, video,data and/or print is used to bridge the instructional gap.

Distance Learning - Learning that takes place while the learner is physically distant from the instructor and from the site of the materials.

Echo Cancellation - The process of eliminating the acoustic echo in a videoconferencing room.

Event Coordinator - Any person wishing to conduct a class, seminar or other activity over the Interactive Video Network.

File Transfer Protocol (FTP) – An application program that uses TCP/IP protocol to allow you to move files from a distant computer to a local computer using a network like the Internet.
Frame Relay - A packet network service, relying on the data integrity inherent in digital transmissions to speed up transmission. Frame Relay assumes the data is correct and starts checking as soon as it receives the header, in a half-dozen error checking steps.

Gateway - A network element that performs conversions between different coding and transmission formats. A gateway is required to connect video systems using different standards. For example, a gateway allows a desktop video system (H.323 standard) to be connected into an IVN event (H.320 standard).

H.320 - The H.320 standard provides a foundation for audio, video, and data communications across dedicated or ISDN dialup-based networks, usually at 128k or above. H.320 is the video standard currently by IVN.

H.323 - The H.323 standard provides a foundation for audio, video, and data communications across IP-based networks, including the Internet. The H.323 video standard is typically used for desktop or Internet video.

Internet, or Internet 1 - 1) Any large network made up of several smaller networks. 2) Capitalized, the international network of networks that connects educational, scientific, and commercial institutions. The common Internet connection used throughout the world by all users today. Can also be called Commodity Internet.

Internet 2 - The high-speed Internet used by educational and research institutions. Use is restricted to specific functions such as research. Other names for Internet2 are “Abilene” and GPN.

IP Address – An identifier for a computer or device on a TCP/IP network. An IP address is a 32-bit numeric address written as four numbers separated by periods. Each set of numbers can be zero to 255. (An example might look like: 123.456.78.9).

ITD Information Services Department. A department of North Dakota state government responsible for all voice, data and video communications for state agencies and higher education institutions. ITD is administered by a CIO appointed by the Governor.

Mbps – MegaBits Per Second. Million bits per second.

MPEG 2 Digital video compression standard set by the Motion Picture Expert Group allowing for the compression of a standard broadcast video channel into a 4 to 6 Mbps datastream. MPEG-2 provides a higher quality picture than MPEG-1 and is better at crisply displaying rapid motion like that found in many televised sporting events. MPEG-2 is rapidly becoming the standard for mass market digital video services such as Direct Broadcast Satellite.

MP3 or MPEG3 – Moving Picture Experts Group. Layer 3 is one of three coding schemes (layer 1, layer 2, and layer 3) for the compression of audio signals. Used for downloading music from the Internet. If you are downloading music from the Internet to your computer to be saved to a CD or loaded to an MP3 player, you are likely to be using this signal format.

Multipoint Videoconference - Videoconference with more than two sites. The sites must connect via a video bridge (MCU or MCS).

Multipoint Conference Unit - A device that bridges together multiple inputs so that more than three parties can participate in a video conferencing. The MCU uses fast switching techniques to patch the presenters or speaker's input to the other participants.

NDIN - North Dakota Information Network. NDIN was created in 1984 as a means for ITD and the NDUS to jointly manage and operate a shared data network. Since then, members have been added to represent the North Dakota Interactive Video Network, state agency and university voice systems, Association of Counties, and the K-12 community. NDIN is the decision making body for all issues dealing with shared telecommunications services.

NDUS - North Dakota University System administered by the State Board of Higher Education.

Point-to-Point Videoconference - Videoconference between two sites.

Router - A network device that examines the network addresses within a given protocol, determines the most efficient pathway to the destination, and then routes the data accordingly. Operates at the Networking Layer of the OSI model.

Server - A computer with a special service function on a network, generally receiving and connecting incoming information traffic.

Site Coordinator - Person designated by the campus (or site) to coordinate on-campus details in IVN room scheduling. Handles the local arrangements for IVN classes/events.