A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

10Base-T -- An IEEE standard (802.3) for operating 10 Mbps Ethernet networks with twisted-pair cabling and a wiring hub, referred to as a 10Base-T hub. 

Analog -- A way of sending voice, video, or data that is "analogous" to the original signal. Analog transmission is associated with voice and data signals over conventional telephone lines. (Contrast with digital). 

Application -- Functional system made up of software, hardware, or combination of both, that performs some useful task. Database managers, spreadsheets, word processors,  videoconferencing systems, LANs, fax machines, etc., are examples of applications. 

Ascend Inverse Multiplexing Protocol (AIM) -- An in-band protocol used to manage the interconnection of two remotely located inverse multiplexers. AIM is a feature-rich, widely used inverse multiplexing protocol developed and supported by Ascend Communications. 

Asynchronous Transfer Mode (ATM) -- A high bandwidth, controlled-delay fixed-size packet switching and transmission system. Uses fixed-size packets also known as "cells"; ATM is often referred to as "cell relay." ATM will provide the basis for future broadband ISDN standards. 

Authentication -- Authentication is a procedure that establishes the legitimacy of users and defines the parameters of the sessions they establish. As such, authentication can be thought of as a security measure that controls and defines network access. It is always the first part of a session; the range of authentication parameters that can be set depend upon the specific authentication systememployed. 

Backbone -- The part of the communications network intended and architectured to carry the bulk of traffic. Provides connectivity between subnetworks in an enterprise-wide network. 

Bandwidth -- Bandwidth is the data capacity of a service,  measured in thousands of bits per second (kbps) or millions of bits per second (Mbps). Bandwidth is not a measure of speed. It is the size of the data payload of the service measured in bits per second. T1 service delivers 1.544 Mbps, whereas ISDN service delivers 128 kbps. The data travels over the line at the same speed, but for T1 lines, the capacity is twelve times that of ISDN. Speed and capacity are two different attributes. For example, if you send yourself two packages via an overnight service--a box with many pages of text, and an envelope with one page of text--the speed at which the packages travel is the same, but the capacity of the box is greater. You may wonder why modem speeds are different if data travels across the line at the same rate--all should deliver the same amount of data per second, right? Differences in encoding methods and compression give modems the ability to transmit data in more and more efficient ways. Signal- encoding schemes and software built into a modem determines its data rate. Advertised throughput, however, is decreased by latency. 

BONDING -- Bandwidth ON Demand Interoperability Group A consortium of over 40 data communications equipment vendors and service providers who are joined together to create a standardized inverse multiplexing protocol so that inverse multiplexers from different vendors can interoperate. Also refers to the resultant specification, sometimes known as the "BONDING specification." 

Bps -- Bits per second. Actually a nested acronym, meaning binary digits per second. 

BRI -- Basic Rate Interface. One of two subscriber "interfaces" in ISDN. BRI has two bearer B-channels at 64kbps and a data D-channel at 16 kbps. The B-channels are for voice, video, and data. The D-channel is for signaling between telephone company switches and for carrying ISDN user-network messages. 

Bridge -- A device or setup that connects and passes data, voice, or video between two network segments, based on the destination field in the packet header. The Pipeline 25 is a learning bridge, because it passes all packets to the next network segment (the ISDN line), and builds a table to identify the destination addresses that are local and remote. After learning the addresses on both sides of a network, the bridge passes only packets for the remote network.

Broadband -- A way of transmitting large amounts of data, voice, and video that is greater than standard voice grade transmission. In ISDN, broadband channels support rates above the primary rate (1.544 Mbps or 2.048 Mbps). 

CCITT -- Consultative Committee on International Telegraphy and Telephony 

Central Office -- A telephone company facility that joins subscriber telephone lines to switching equipment. This allows subscribers to connect to one another, through local and long distance connections. 

CODEC -- COder-DECoder. In the videoconferencing world, a video codec converts analog video signals from a video camera to digital signals for transmission over digital circuits, and then converts the digital signals back to analog signals for display. In the audio world, an audio codec converts analog audio signals to digital signals for transmission over digital circuits, and then converts the digital signals back to analog signals for reproduction. 

Compression -- Compression is a technique that reduces the quantity of bandwidth or bits required to encode a block of information. Compression saves transmission time and capacity, and can free up storage space on in-demand data lines. Compressed data can be compromised in quality, but the advantages of bandwidth savings are frequently worth the trade-off. Compression is not yet standardized. 

Digital -- A way of sending voice, video, or data that reconstructs the signals using binary codes (1s and 0s) Digital transmission offers faster speeds, better accuracy, and more flexibility than analog transmission. (Contrast with analog). 

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Ethernet -- A local area network that connects devices like computers, printers, and terminals. Ethernet operates over twisted-pair or coaxial cable at speeds at 10 or 100 Mbps. 

Firewall -- A hardware/software tool that allows a network administrator to determine what type of users can access the resources on the network. The firewall provides a mechanism to monitor and funnel data from authorized users (only) through the firewall to and from the network. A firewall may be a software program that runs on UNIX or other platforms, or it may be a part of a proprietary operating system. 

FR -- Frame Relay. A form of packet switching, but using smaller packets and less error checking than traditional forms of packet switching (such as X.25). Now a new international standard for efficiently handling high-speed, bursty data over wide area networks. 

Fractional T1 -- Service offering data rates between 64 kbit/s (DS0 rate) and 1.536 Mbit/s (DS1 rate), in specified intervals of 64 kbit/s. 

Frame Rate - Frames per second (fps) displayed on a video monitor; 25-30 fps is "full motion."

Gateway -- Gateways are points of entrance to and exit from a communications network. Viewed as a physical entity, a gateway is that node that translates between two otherwise incompatible networks or network segments. Gateways perform code and protocol conversion to facilitate traffic between data highways of differing architecture. In OSI terms, a gateway is a device that provides mapping at all seven layers of the OSI model. A gateway can be thought of as a function within a system that enables communications with the outside world. 

H.320 -- A set of CCITT standards describing methods to allow videoconferencing terminals from different manufacturers to interoperate. 

IEEE -- Institute of Electrical and Electronics Engineers. An organization that maintains the standards for 10BaseT and other communications standards. 

Internet Gateway -- A gateway (see Gateway) for accessing the Internet, which is loosely defined as the complex of wide area networks joining government, university, corporate and private computers (nodes) in a vast web of network interconnection. 

Interoperability -- Interoperable devices are compatible with the devices and services of multiple vendors, and can be integrated into a generic network containing a wide range of vendor products. Interoperability is a significant factor among expansion considerations, since any device must have the versatility to function in an expanding network structure. The technical elements of interoperability may include a bundle of protocols and a flexible architecture to accommodate upgrades. A remote access server should include capabilities such as translation, encapsulation,  filtering, etc., that enable internetworking. 

Inverse Multiplexer --  an electronic device that enables two or more signals to pass over a single communications circuit, whether analog or digital. An  inverse multiplexer allows individually dialed channels across a network to be combined into a single, higher-speed data stream. Each end of the connection uses an inverse multiplexer, or inverse mux. 

IP -- Internet Protocol 

IP Address -- An address that uniquely identifies each host on a network or Internet. 

ISDN -- Integrated Services Digital Network. A system that provides simultaneous voice and high-speed data transmission through a single channel to the user's premises. ISDN is an international standard for end-to-end digital transmission of voice, data, and signaling. User networks can dial network channels of bandwidth in incriments of 64 kbit/s, up to 1536 kbit/s.

ISDN BRI Line -- An ISDN Basic Rate Interface line that uses two B channels for user data, and one 16-kbps D channel for ISDN D-channel signaling. Both B channels can be switched, both channels can be nailed up, or one channel can be switched and the other nailed up. BRI stands for  Basic Rate Interface. A line of this type can connect to standard voice service, Switched-56 data service, or Switched-64 data service. 

ISP -- An Internet Service Provider is a company that provides access to the Internet. By establishing Points of Presence (POPs) containing remote access servers and additional devices, as well as a suite of user software packages, the Internet Service Provider acts as a commercial Internet on-ramp. Providers typically charge a monthly fee and supply technical support and advice to customers. 

Kbps -- kilobits per second 

LAN -- A network that interconnects devices over a geographically small area, typically in one building or a part of a building. The most popular LAN type is Ethernet, a 10 Mbps standard that works with 10BaseT, 10Base2, or 10Base5 cables. 

Mbps - Megabits - Megs - millions of bits ber second.

MCU -- Multipoint Control (or Conferencing) Unit -- Bridge -- enables participants at more that two sites to participate in voice or video calls.

Nailed Line -- A permanent connection between endpoints over which two parties exchange data. A nailed line is also known as a private line or a leased line. 

NTSC - National Television Systems Committee - A video signaling standard for North American TV sets with a display rate of 30 fps and 352-525 scan lines.

PAL - Phase Alternation Line -- A European alternative to NTSC, with better color resolution and an increase in scan lines to 625 over NTSC's 525.

PRI, ISDN PRI --  Primary Rate Interface -- An ISDN subscriber line, consisting of twenty-three 64 kbit/s B channels in North America (thirty 64 kbit/s channels elsewhere) and one 64 kbit/s D channel, used for signaling purposes. 

POTS -- Plain Old Telephone System -- The analog, public switched telephone network in common use throughout the world.

Presets - Determines how many predefined camera positions can be set.

SPID -- Service Profile Identifier. Your ISDN service provider (telephone company) uses this number at the Central Office switch to identify services on your ISDN line. This number is derived from a telephone number. 

Standards -- ITU-T Standards- International Telecommunications Union established standards enabling free interchange of voice, video and data information among various vendors. 

T1 - A leased digital line that provides 1.544 Mbps data rate (in North America; European T1 delivers 2.048 Mbps)

TeleMedicine - videoconferencing for specific medical applications. Examples include Critical CareLink that links doctors and nurses on the East and West Campus ICU units, Interpreters CareLink that connects language interpreters with patients who do not speak English or are hearing impaired and BabyCareLink that enables parents of newborns in the NICU to interact with their child and the child’s doctor and nurses from their home.

USB - Universal Serial Bus - A "plug and play" interface between a computer and an add-on device such as audioplayers, keyboards, telephones, scanners and printers.

WAN - Wide Area network  - A LAN with a wider geographic scope.

Videoconferencing -- The use of digital video transmission systems to communicate between sites using video and voice. Digital video transmission systems typically consist of camera, codec (coder-decoder), network access equipment, network, and audio system. 

VideoStreaming (http://www.unc.edu/courses/ssp/streaming/streaming.html)