Videoconferencing Glossary
From A like Adapter ...
In our extensive glossary, you will find a list of
the most important terms and abbreviations from the area of video
communication.
the most important terms and abbreviations from the area of video
communication.
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- >>a/b-Adapter
Device and interface to operate analogue devices under ISDN. - >>1TR6
National German ISDN protocol. After the year 2000, 1TR6 is completely removed by the Euro-ISDN protocol DSS1. - >>ADSL
Asymmetric Digital Subscriber Line. Like ISDN, ADSL uses simple copper lines for digital data transmission, however it works at higher transfer rates. In ADSL, with two copper wires of a telephone connection one can achieve up to 640 KBits/sec in upstream and even up to 6 MB/sec in downstream (ISDN: 64 KBit/s). Various European telecommunication companies are planning to introduce the ADSL technology. - >>Aggregation
Channel negotiation in ISDN. - >>Alternating tele work
In this form of tele work, not only does the employee have a workplace on the employers premises, but also one in his own home, whereby he can choose to work from either location.
top- >>AMX
Manufacturer touch-sensitive, programmable media control units - >>Application Sharing
Indicates common viewing and processing of documents and files, and online exchange at video conferences. The ITU recommendation is the standard for application sharing, which is also supported by the Microsoft Netmeeting Software. Thereby, participants of a video conference can access programs on a participants computer and work together on it. - >>Asynchronous
In this data transmission procedure, the data is not transmitted at the same frequency. Therefore, control bits are necessary to signal the start and end of a byte. - >>ATM (Asynchronous Transfer Mode)
An asynchronous, transmission standard, which presents the basis for broadband ISDN. Voice, data and images are transmitted using this type of transmission. An agreement of five European network operators has established ATM as the future standard. - >>Automatic Call Distribution
Automatic distribution of incoming calls to free workplaces.
top- >>Bandwidth
Term for the transmission capacity of a system. Unit determination, in e.g. Herz or Bit/s. - >>Basic connection
A variant of a subscriber line in the ISDN. The ISDN basic line comprises two basic channels (B-channel) at 64 kb/s each and signal channel (D-channel) at 16kb/s. - >>Picture division
See Continuous Presence - >>B-channel
Abbreviation for bearer channel - >>Bonding
Abbreviation for Bandwidth on Demand Interoperability, group name of a consortium and name of a transmission standard for inverse multiplexing with five different modes. With the Mod1 applied for video conferencing, data is transmitted to multiple channels independently of one another, without any synchronization and error correction. If an error occurs, the entire connection is broken.
top- >>Bridge
Connection between two or more networks. A bridge can only connect networks with the same topology (e.g. Ethernet) and the same protocols. Also see MCU - >>BRI
Basic Rate Interface. International name for ISDN basic line. - >>Business-TV
Quicker information flow through company television between employees of big, decentralised companies. Target is to transmit work-specific information to closed user groups. - >>Call Center
Group work place for inbound and outbound calls with database support. Special functions here are e.g. Automatic Call Distribution and PowerDial. - >>Cart
Cart for monitors
top- >>CAPI
Common ISDN-API. Standardized interface for ISDN cards - >>CCITT
Consultative Committee for International Telephony and Telegraphy. International consultative committee that deals with the standardization of data and remote telephone services. - >>CIF
Abbreviation for Common Intermediate Format, indicates the format of a picture, which belongs to a video sequence and was coded in compliance with H.261. Often also called Full-CIF. The resolution is 288*352 pixels at a frame frequency of max. 30 frames. - >>Chairman
Is a conference leader function in multipoint conferences. The Chairman determines which location must be seen for everybody in the frame - >>CODEC
Coding/Decoding and Compression/Decompression of signals according to a definite procedure during a video conference. The procedures were standardized by the ITU. The conversions are made by a special CODEC card where the communication interfaces (ISDN/LAN) are also generally housed.
top- >>Corporated Network
Means same telecommunication environment, regardless of whether employees from a company work in the Munich, Düsseldorf or Paris branch. Virtual private networks allow the employees to communicate in such a way as if a uniform inhouse company network were used. - >>Continuous Presence (Quarter split)
Is a form of multipoint conference where multiple locations can participate in picture and sound. Here, the screen of all participating locations is divided into max. 9 sections. Each location is mapped in a section - >>Cryptor (Encryptor)
Encryptor and decryptor are used to make data communication bug-proof. The encryption systems must be installed at transmission and reception location. - >>Data compression
Tool to increase the real data transmission output. During this process, the data is compressed by applying appropriate mathematical processes. - >>DDC
Dynamic Data Channel, is a protocol for data communication between video conferencing systems.
top- >>D-Channel
Abbreviation for data channel, indicates the signal channel in ISDN. The D-channel has a data rate of 16 kb/s in basic line and 64 kb/s in primary multiplex line. The connection is established, cut off and controlled through the D-channel. - >>Downspeeding
Safety function, which during a breakdown of some B-channels is used for the communication to avoid a complete interruption of the transmission. - >>DSP
Digital Signal Processor or one-chip microcomputer, which controls processes independently in the electronic system environment and takes over computing operations. - >>DSS1
Digital Subscriber Signaling System No.1. European ISDN protocol. - >>E1
Abbreviation for European Digital Signal Level No. 1. Data rate of the European multiplex hierarchy standardized by the ITU. E1 corresponds to 2.048 Mbit/s and comprises of 32 channels each with 64 kb/s, 30 usable channels and an additional service and signaling channel. The counterpart in North America is T1.
top- >>Ethernet
EDP Network with bus-like structure. The most widely used technology today for local networks. - >>Frame Relay
Standardized, packet-oriented transmission protocol for point-to-point connections. - >>Fixed line
Permanent active connection between two sub networks in the network. No other subscriber can use this connection. - >>Firewall
A Firewall helps to wall-off data networks. All data traffic between inside and outside must pass the Firewall, only the traffic provided in the security concept is guided through. - >>Frames
Screen structure in monitors (1 Frame = 1 image)
top- >>Gatekeeper
Registration of the end systems and the central components. - >>Gateway
Interface between various networks. Translates interface protocols from non-compatible networks. Facilitates connections between subscribers in various networks. - >>Gateway (in video conferencing)
A Gateway allows H.323 compatible systems to communicate with H.32x remote stations. The Gateway can, e.g. connect the H.323 System with a H.320 (ISDN), H.321 (ATM), H.322 (ISO Ethernet) or H.324 (PSTN) based system. At present, a H.323 to H.320 connection (LAN/ISDN) is still the most usual form of use of a VC Gateway. - >>Groupware
Programs for organization and management of business operations - >>H.221
ITU-T recommendation with reference to audio-visual tele-services.
top- >>H.223
ITU-T recommendation: Multiplex protocol for multimedia communication with low bit rates. - >>H.230
ITU-T CODEC recommendation with reference to the H.230 frame synchronization control and the control signals for audio-visual systems. - >>H.231
ITU-T MCU recommendation for bridges with channels up to 2 Mbps. - >>H.242
ITU-T CODEC recommendation for a system that facilitates the connection between two audio-visual terminals that use digital channels up to 2 Mbps. - >>H.243
ITU-T recommendation: Process for establishing communication links between three or more audio-visual terminals that use digital channels up to 2 Mbps.
top- >>H.245
ITU-T recommendation: Control protocol for multimedia communication - >>H.261
ITU-T CODEC recommendation for a Video-CODEC, which enables audio-visual services with n * 64 kbps. Unfortunately, the motion compensation and the field scanning (loop filter) is only an optional extension of the standard. Users that take an ITU-T CODEC for the range 384 kbps into consideration should make sure that the manufacturer has implemented these options. - >>H.261 Annex D
ITU-T CODEC recommendation for the simultaneous transmission of graphics data in the North America region. Other regions can also use JPEG. - >>H.263
ITU-T recommendation: Video coding for the communication of audio-visual services in the range of low bit rates. Extends the capabilities of the H.261 standard considerably because the quality of low-resolution images in the size of a credit card can be extended to extraordinarily detailed and high quality images. This can, e.g. be used for tele-medicine applications. H.263 is backward-compatible to the QCIF (Quarter Common Intermediate Format) and optional also to the CIF and SQCIF (Sub-QCIF) of the H.320 standards. - >>H.320 specification
ITU-T CODEC recommendation that combines other recommendations with the purpose of producing a general "Video telephone" system specification.
top- >>H.321
ITU-T recommendation that describes the ATM-based local area networks. - >>H.322
ITU-T recommendation that describes video systems and terminals for local area networks with guaranteed bandwidth (Quality of Service). This standard directly refers to the IEE P802.9a draft, treating LANs with low response time that are required for video communication. - >>H.323
ITU-T recommendation that describes video systems and terminals for local area networks without guaranteed bandwidth (Quality of Service). - >>H.324 specification
ITU-T recommendation that describes a terminal for the multimedia communication at low bit rates. This includes various other recommendations such as a video CODEC for low speed connections via V.34 analog telephone lines, as well as ATM, ISDN and possibly mobile connections. The combination of various recommendations has the aim of creating a general system specification for a video telephone. Compatibility with H.320, network code conversion, multipoint support and continuous presence are available. - >>Channel bundling
Combination of multiple B-channels. They are bundled with a virtual channel with a higher data transmission rate.
top- >>HDTV
High-Definition TeleVision. Any television standard that has a display ratio of about 2:1, and is qualitatively much better than NTSC or PAL. - >>Huffman coding
A loss-free coding technology that determines the information content of an image statistically. The data is compressed in such a way that the data groups that appear mostly with short codes represent the less frequent data groups with longer codes. The Huffman coding is used in the H.320 and other video communication CODECs, as well as in the Group-3 Fax and in JPEG format. - >>ICM
Intelligent Call Management is a feature, which dynamically divides and controls the transmission bandwidth between video, audio and data. - >>IMUX
Inverse multiplexer: Device for transmission management while using multiple ISDN channels for video or data communication. - >>Interactive multicast
Interactive video, audio and data connection to multiple users in the LAN.
top- >>IP
Internet protocol. Network protocol in different networks. - >>ISDN
Integrated Services Digital Network. Digital network that offers all services (voice, text, images, data) through one connection. - >>ITU
International Telecommunications Union, committee of the United Nations Organization (UNO), to which 113 countries belong. Task is the standardization of transmission formats in the telecommunication and global networks. - >>JPEG
Abbreviation for Joint Photographic Expert Group, started out as the name of a standardization committee, then itself became the denomination of a compression process for still images. - >>Channel
In transmission technology, an installed (unidirectional) point-to-point connection for transmission of signals.
top- >>Short-term rental pool
A trend is taking root: More and more companies are renting mobile video conferencing devices when required. We offer video conferencing systems adapted to the customers requirements. Moreover, the range of products includes a large selection of accessories, such as: Document camera, VGA/PAL converter, large image projections, public address systems etc. - >>LAN
Abbreviation for Local Area Network, network of computers within a limited area. - >>Lime-Light
Commercial name of PictureTel for the camera with voice tracking. The camera automatically orients itself to the speaker in the conference room. - >>Management Server
Centralized management and monitoring; bandwidths, priority and remote management; billing and reporting tools, integration of online directories and integrated gatekeeper. - >>MCU
Abbreviation for Multipoint Control Unit. An MCU is required for conferences with more than two video conferencing systems. It makes it possible to interconnect all participants to a common conference.
top- >>Multipoint conference server
Conducting multipoint conferences with IP and ISDN subscribers. - >>Rental pool
A trend becomes standard: More and more companies are renting mobile video conferencing devices from the telecommunication company Deutsche Telekom when needed. Deutsche Telekom offers customized video conferencing devices that match the customer requirements. Moreover, the range of products includes a large selection of accessories, such as: Document camera, VGA/PAL converter, large image projections, public address systems etc. - >>MPEG
Motion Picture Experts Group. An ISO standard for moving image and audio compression, which allows high loss and loss-free compression. Is used for recording multimedia images from CD-ROM, for Pay TV, broadcasting and is suitable for video communication. - >>Multiplexer
See IMUX. - >>NDIS
Network Driver Interface Specification, interface definition between the operating system of a local network and the network adapter.
top- >>NetMeeting
Microsoft NetMeeting enables users to jointly use audio, video, data and applications in real time through various connections. - >>NT
Network Terminator (device used as network termination of the network provider). - >>NTSC
Abbreviation for National Television Standards Committee US television standard. NTSC signal is a composite signal that was taken over by the television and video industry in USA and Japan. - >>PAL
European standard for video (current frequency 50 Hz) - the television standard applied in Germany and other parts of Europe. - >>PBX
Private Branch Exchange
top- >>PCI
Bus format for PC plug-in cards. - >>Plug & Play
Figure of speech is used when the installation and configuration of a device or software is a very easy task. - >>POTS
Plain Old Telephone Service. Analog telephone line that uses e.g. TwistedPair cable for transmission of modulated voice signals. Also see PSTN. - >>PPP
Point-to-Point-Protocol. Standardized protocol for establishing remote data connections. - >>PSTN
Public Switched Telephone Network called the (analog) public telephone fixed network.
top- >>Quality of Service
QoS guarantees an application specific required network resources in the form of a guaranteed bandwidth. Essential aspect for video conferencing and voice over IP (VoIP). - >>Quarter split
See Continuous Presence. - >>Remote management
Device control from a remote point. - >>Rollabout
- >>Router
Connection of multiple networks. The networks can be different (e.g. Token Ring and Ethernet).
top- >>S0
ISDN connection, comprising two B-channels and a D-channel, also see basic connection - >>S0 interface
ISDN connection, comprising two B-channels and a D-channel, also see basic connection - >>S0-Bus
See multidevice connection - >>SoftMux
Software-based IMUX (see IMUX), proper name of Tandberg. - >>SOHO
Small Office Home Office: Name for the office or working place at home.
top- >>S2M
ISDN connection, comprising 30 B channels and one D-channel. Also see primary multiplex connection - >>Scart socket
Also called Euro-AV socket. Refers to the socket for television and video recorder. - >>SCSI
Abbreviation for Small Computer System Interface. Refers to a PC interface to connect peripheral devices (e.g. scanner). - >>Standard connection
ISDN connection with standard service features that are however fully suitable for connecting a video conferencing end device. - >>Voice control
See Voice controlled
top- >>T1
Abbreviation in the USA for a standardized data connection. T1 corresponds to 1.544 Mbps and generally comprises of 24 ISDN channels of 56kb/s each, 24 signal channels at 8kb/s each and a 8k-bit control channel. The counterpart in Europe is E1. - >>T.120
ITU-T standard that regulates the real time data conference. Parallel to video conferencing, it is possible to use application sharing, file transfer, chat or whiteboarding. - >>T.120 specification
A general ITU-T outline recommendation that describes the transmission protocols for multimedia data. It contains multilayer protocols that increase the multimedia, MCU and CODEC control capabilities considerably. As a result, a sophisticated MCU mode much superior then the H.231 and H.243 standards is possible. - >>T.121
ITU-T recommendation that describes a generic template for applications. - >>SIP Protocol
The Session Initiation Protocol (SIP) was developed for transferring multimedia-applications. SIP is based on SMTP and HTTP but incompatible with H.323 or H.320. The client-server-model is a conceptual substructure. The participant needs a client and every data-stream is distributed by a central server.
top- >>T.122
ITU-T recommendation that describes the multipoint communication services (MCS) for audio graphics and audio visual conferences. In the definition phase. - >>T.123
ITU-T recommendation that describes the protocol stacks for audio graphic and audio visual teleconference applications. A finished version is available, and a new suggestion has been presented in the meantime (10/95). - >>T.124
ITU-T recommendation for a generic conference control for audio graphic and audio visual terminals. - >>T.125
ITU-T recommendation that describes the specifications for multipoint conference service. - >>T.126
ITU-T recommendation that describes the protocol specifications for still image conferences.
top- >>Transmission rate
Speed at which data or video signals are transmitted. This is normally specified in bps. - >>T.127
ITU-T recommendation that describes the protocol specifications for multipoint data transmission of binary files. - >>T.128
ITU-T recommendation for checking audio visual multipoint multimedia systems. - >>TCP/IP
Abbreviation for Transmission Control Protocol/Internet Protocol The IP protocol defines the setup and addressing of data packets in TCP/IP networks. The TCP protocol is established on the IP protocol, provides for the sorting of packets into the correct sequence and is responsible for confirming reception. Transmission errors are automatically corrected - >>Telecoaching
Describes a specific support of skills and knowledge or practices via an online connection between teacher/teletrainer and student/trainee. Also see Telelearning
top- >>Telediagnosis/ Teleservice
Remote diagnosis and maintenance: Locating errors and problems in electronic devices, machines and computers their maintenance through telecommunication connections. - >>Telelearning
Learn with the help of modern information and communication technology - >>Telematics
Generic term for the telecommunication and informatics subject areas (taken from the French term Télématique), synonymous with the English term compunication that is a composition of computer and communication. - >>Telelessons
In telelessons, i.e. while distributing knowledge across large distances, when as often happens in Australia teachers and students live hundreds of kilometers away from each other, systems for computer-supported lessons are particularly valuable. - >>Telelectures
Telelectures at a university or school for video conferencing technology where the tutor is not in the same room as the audience.
top- >>Touch screen
Touch sensitive screen. - >>TFT display
Term for flat screens with active internal lighting. - >>Voice controlled
Means that the person talking in a multipoint conference is seen by all the connected participants. - >>WAN
Abbreviation for Wide Area Network A private or public network with a reach of more than 10 km. This frequently connects multiple LANs with one another. The network used for this purpose can be an ISDN line. - >>Western plug
Term used for a plug used worldwide in telecommunications.
top- >>Whiteboard
Commonly used window in video conferencing for diagram presentation. In normal meetings, white wall boards are used on which one writes with special board markers and that can be wiped clean with a dry cloth. - >>X.21
Interface description of the ITU for synchronous transmission between end device and transmission device. - >>Signaling
Signaling:Term for all instructions for exchange of information that involve the setup, disconnection and control of a connection in a telecommunication network.




