Asynchronous. A type of two-way communication that occurs with a time delay, allowing participants to respond at their own convenience. Literally not synchronous, in other words, not at the same time. Example of an application of asynchronous communication is electronic bulletin board.

Audioconference. An electronic meeting in which participants in different locations use telephones or audioconferencing equipment to interactively communicate with each other in real time. The number of participants may be as small as 3 or as large as 100 or more.

Broadband. The term applied to networks having bandwidths significantly greater than that found in telephony networks. Broadband systems are capable of carrying a large number of moving images or a vast quantity of data simultaneously. This may be important if your class has streaming video or large graphics which is usually not available over dial-up networks.

Blackboard Learning Systems. A CMS, content managment system, to assist instructors in providing internet course materials including web pages, e-mail, bulletin boards, discussions, and other tools. WebCT was purchased by and has become Blackboard Lerning Systems.

Collaborative/Cooperative Learning. The process of getting two or more students to work together to learn. Sometimes a distinction is made between the two terms based on the age of the learners: cooperative for K-12 education and collaborative learning for adult education, and some practitioners contend that there are important differences between the two based on the unique pedagogical needs of each corresponding age group. However, the terms are often used interchangeably.

Computer-assisted Instruction (CAI). See Computer-based Training (CBT).

Computer-based Training (CBT). An interactive instructional approach in which the computer, taking the place of an instructor, provides a series of stimuli to the student ranging from questions to be answered to choices or decisions to be made. The CBT then provides feedback based on the student's response.

Computer Conferencing or Web Conferencing. An ongoing computer conversation via text with others in different locations. Conferencing can be done in "real time," so that messages appear as they are being keyed, or it can be "asynchronous," which means the complete message is keyed and then stored for later use by the receiver or sender.

Content Managment System (CMS). Any of a variety of computer programs that provides a shell for an online course. A variety of tools including web pages, e-mail, bulletin boards, and discussions threads may be provided.  

Course Compass. A CMS, content managment system, used by many publishers. 

Course Pack. A distance learning package supplied by a textbook publisher, usually used in conjunction with a specific text. Most popular in computer-based training.

Desktop Videoconferencing. Videoconferencing on a personal computer equipped with a fast Internet connection (at least 28.8 Kbps modem), a microphone, and a video camera . There can be two-way or multi-way video and audio depending upon the hardware and software of participants. Most appropriate for small groups or individuals. Not yet presently available in many parts of the country due to bandwidth and equipment limitations for this application.

Dial-up Network. An internet service provider who connects, usually by modem, at low bandwidth (low baud rate) usually through standard phone lines. Downloading streaming video or large graphics may be difficult using dial-up.

Distance Communication. Use of telecommunication technology for the implementation of administrative activities such as meetings, focus group, or job interviews when the parties are located at two or more locations.

Distance Education. See Distance Learning. The term distance education is often used synonymously with distance learning. However, distance education typically refers to distributed learning resources in academic settings.

Distance Learning. A system and a process that connects learners with distributed learning resources. While distance learning takes a wide variety of forms, all distance learning is characterized by the following: 1) separation of place and/or time between instructor and learner, among learners, and/or between learners and learning resources, and 2) interaction between the learner and the instructor, among learners, and/or between learners and learning resources conducted through one or more media; use of electronic media is not necessarily required.

Distributed Learning. See Distance Learning. This term survives from the days of correspondence courses.

Document Camera. A device to display a variety of documents through a network. Essentially a video overhead projector.

DVD. This once stood for digital video disc or digital versatile disc, but now it just stands for DVD -- the next generation of optical disc storage technology. DVD is essentially a bigger, faster CD that can hold cinema-like video, better-than-CD audio, and computer data.

Emoticon. Also known as smilies, they are keyboard characters used in combination to produce whimsical symbols representing a range of emotions. Examples are happy :-)  and sad  :-( . Emoticons are used in electronic communication to show humor and express emotions that are difficult to communicate in a text-based environment. For a comprehensive list of emoticons, click on this link: http://www.chatlist.com/faces.html

F2F. Face-to-face. This term is used to describe the traditional classroom environment.

Facilitative Tools. Electronic applications used in online courses as part of the course delivery. Examples are mailing lists, chat programs, streaming audio, streaming video, Web pages, etc. A successful online course will contain a combination of these tools, but it is neither necessary nor desirable to use all of them. Facilitative tools should be selected according to their added value to the course material and whether they are useful in achieving the learning outcomes of the course.

Facilitator. The online course instructor is often referred to as the course facilitator. Online instructors do not retain their traditional "teacher-centered" roles from the onground paradigm. Instead, they become the medium through which discovery learning is facilitated in a student-centered environment.

Facsimile Machine (fax). A telecopying device that electronically transmits written or graphic material over telephone lines to produce "hard copy" at a remote location.

FAQ. List of frequently asked questions and their answers.

Instructional Multimedia. A form of computer-based training that incorporates a mix of media as the stimulus to the student. Possible media elements include sound, animation, graphics, video, text; whatever it takes to get the instructional message across to the target audience. (See Multimedia)

Instructional Design (ID). Systematic approach to the planning and development of a product to meet instructional needs and goals. All components of the system are considered in relation to each other in an orderly but flexible sequence of processes. The resulting instructional product is tried out and improved before widespread use is encouraged.

Interactive Video. Combination of a videodisc (usually laserdisc) or videotape and computer system that permits user response and participation, allowing for direct exchanges between user and software or among people. This instructional medium has limited use today.

Interactive Television (ITV). Two-way instructional videoconferencing emphasizing the ability to minimize the transactional distance of those involved in the educational process.

Instructional Television (ITV). One-way video presentation which may be view asynchonously often from VHS tape. This is one component of  a Telecourse.

Interactive Videoconference (IVC). See Interactive Television. Different institutions use different acronyms.

Internet Courses (NET). Students participate in the class by using the Internet for all or part of the coursework. The instructor posts a Web page which contains all relevant course information and assignments. Communication between students and instructors can occur by e-mail, telephone, fax, mail, or face-2-face. Also see web-based training.

Learning Management System (LMS). See Content Management System.

ListServ. Mailing list program for communicating with other people who have subscribed to the same list using e-mail. When you submit a message to the server, your message is relayed to all those on the listserv. You receive messages from other participants via e-mail. It is similar to computer conferencing, but a listserv is asynchronous.

Logging On. Connecting to a computer network or content managment system, typically through the use of a personalized identification code.

Lurking. A person is lurking when he/she reads the postings in a discussion forum but does not contribute to the discussion. It is important for an online instructor to be somewhat accepting of lurkers since students have different learning styles and some learn better by listening. However, it is also important to encourage lurkers to become active participants in order for them to take full advantage of the online paradigm.

Multimedia. Systems that support the interactive use of text, audio, still images, video, and graphics. Each of these elements must be converted in some way from analog form to digital form before they can be used in a computer application. Thus, the distinction of multimedia is the convergence of previously diverse systems.

Netiquette. People navigating in a virtual environment must follow proper protocols and have good online "manners"  generally known as netiquette, or etiquette on the Net. For a comprehensive list of rules for a variety of forms of online communication, see Arlene Rinaldi's User Guidelines and Netiquette at Florida Atlantic University: http://www.fau.edu/rinaldi/netiquette.html

Network. A configuration of two or more computers linked to share information and resources.

News Group. Discussion group on the Internet. Similar to electronic bulletin boards. Users are presented with a summary of discussion topics and can select from an organized menu and sub-menu structure.

On-line Courses. See Web-based training.

On-line Environment. Courses, discussions, or other communication occurring in an electronic format via the Internet.

Real Time. The processing of information that returns a result so rapidly that the interaction appears to be instantaneous. Telephone calls and videoconferencing are examples of real-time applications. These kinds of real-time information not only need to be processed almost instantaneously, but it needs to arrive in the exact order it's sent. A delay between parts of a word, or the transmission of video frames out of sequence, makes the communication unintelligible. The telephone network is designed for real-time communication. See Synchronous.

Receiving Sites. All sites, other than the originating site, participating in a course or meeting that is distributed with technology such as audioconferencing or videoconferencing.

Search Engines. Permits searching of documents and databases accessible on the Internet. Search engines can be set up to search only content within one Web site or to search the entire Internet. Many search engine developers have their own web sites such as Google. In addition to search engines there are index sites such as Yahoo, where links to Web sites are organized into categories so that you can browse categories rather than guessing at search terms.

Seamless Technology. In an online course, technology is said to be seamless (or transparent) when it is easy to use, intuitive in nature, and is NOT the focus of the learning experience. If programs are difficult to use and the system has frequent breakdowns, the technology is not seamless and hinders the learning process. Technology should merely be a means to deliver course content, facilitating the learning process.

Streaming Media. Communicating to multiple computers at the same time over Internet by "streaming" live audio and/or live video. Through compression and decompression of the signal, audio and video are experienced in real time over Internet. Examples of commercial products emerging in this area include Windows Media and RealAudio.

Synchronous. A type of two-way communication that occurs with virtually no time delay, allowing participants to respond in real time. Also, a system in which regularly occurring events in timed intervals are kept in step using some form of electronic clocking mechanism. (See Asynchronous)

Synergy. The dynamic energetic atmosphere created in an online class when participants interact and productively communicate with each other and in groups. The cooperative efforts of the participants create an enhanced combined effect compared to the sum of their individual effects. This atmosphere is highly conducive to learning.

Telecommunication. The process of transmitting or receiving information over a distance by any electrical or electromagnetic medium. Information may take the form of voice, video, or data.

Teleconference. Simultaneous conference to multiple sites distributed via audio (phone or other audio). Satellite videoconferences and videoconferences using compressed video are sometimes referred to as "teleconferences." To distinguish more accurately between these frequently used terms, using the term which uniquely describes the communication is preferred.

Telemedicine. Use of telecommunications technology for medical diagnosis and patient care when the provider and client are separated by distance. Telemedicine includes pathology, radiology, and patient consultation from the distance.

Transparent Technology. See Seamless Technology.

Transactional Distance. The perceived separation between parties in distance learning. Lower transactional distances are associated with greater satisfaction in the learning process.

Two-Way Video/Two-Way Audio. Interactive video in which all sites are in visual contact with one another. Some form of audioconferencing is used for real-time verbal interaction.

TXDLA. Texas Distance Learning Association. click here for www.txdla.org

URLs (Uniform Resource Locators). The address system used by the Internet to locate resources such as web sites. An URL includes the type of resource being accessed such as gopher or hypertext), the address of the server, and the location of the file e.g.  http://www.brazosport.edu/~distance/index.html is Brazosport College's URL. "http://" indicates the access method as Hyper Text Transfer Protocol. "www.brazosport.edu" is the address of the server. "/~distance/" specifies the directory the file is located. "index.html" is the initial page of the distance learning web site. Web browsers will assume "http://" and "index.html", so you can simply use www.brazosport.edu/~distance/ as the URL.

USDLA. US Distance Learning Association. click here for www.usdla.org

Videoconference. A meeting, instructional session, or conversation between people at different locations relying on video technology as the primary communication link. Communication is 2-way audio with either 1-way or 2-way video. The term, videoconference, is sometimes used to refer to conferences via compressed video, conferences via land lines, and broadcasts via satellite. To avoid confusion, using the term or phrase which uniquely describes the communication technology is recommended.

Virtual Classroom (VC). An online discussion forum where most of the conversations relating to the coursework take place (either synchronously or asynchronously). The VC is usually physically a folder in a conferencing system where students and professor post their messages. It is a public forum in the sense that all participants can read and respond to any message posted to the VC.

Web-based Training (WBT). A form of computer-based training in which the training material resides on web pages or a CMS accessible through the World Wide Web. Typical media elements used are text and graphics. Other media such as animation, audio, and video can be used, but require more bandwidth and in some cases additional software. The terms "on-line courses" and "web-based instruction" are sometimes used interchangeably with WBT. Also see internet courses.

WebCT (Web Course Tools). A CMS, content managment system, program to assist instructors in providing internet course materials including web pages, e-mail, bulletin boards, discussions, and other tools.

Web Conferencing or Computer  Conferencing. An ongoing computer conversation via text with others in different locations. Conferencing can be done in "real time," so that messages appear as they are being keyed, or it can be "asynchronous," which means the complete message is keyed and then stored for later use by the receiver or sender. Common providers include Embanet, Horizen, and WebEx.

Whiteboard : A term used to describe the placement of shared documents on an on-screen "shared notebook" or "whiteboard." You may use familiar Windows operations (cut and paste) to put snapshots on the whiteboard or you may work with familiar tools to mark up the electronic whiteboard much like you do with a traditional wall mounted board.

Analog. A form of transmitting information characterized by continuously variable quantities, as opposed to digital transmission, which is characterized by discrete bits of information in numerical steps. An analog signal is responsive to changes in light, sound, heat and pressure.

Address Mask. A bit mask used to select bits from an Internet address for subnet addressing. The mask is 32 bits long and selects the network portion of the Internet address and one more bits of the local portion. Sometimes called subnet mask.

Analog Communication. A communication format in which information is transmitted by modulating a continuous signal, such as a sound wave. Current TV and radio signals are analog, as are many telephone lines. See also Digital Communication.

ASCII. American Standard Code for Information Interchange. Standard 8 bit code used in data communications. Many files interchanged from one software program to another and from IBM to Mac formats go through translation into ASCII.

Authoring Software/Tools. High level computer programs designed for use by non-programmers in the creation of computer-based training, interactive presentations, and multimedia. The commands are presented as simple terms, concepts, and icons. The authoring software translates these commands into the programming code needed by the computer and related hardware devices.

Bandwidth. Maximum frequency that can be used to transmit a communication signal without excessive distortion. Measured in Hertz or cycles per second. The more information contained in a signal, the more bandwidth it requires for distortion-free transmission.

Baud Rate. The transmission rate at which data flows between computers. The baud rate is roughly equivalent to the number of bits per second (bps).

Bit (binary digit). The smallest unit of information a computer can use. A bit is represented as a "0" or a "1" (also "on" or "off"). A group of eight bits is called a byte. Bits are often used to measure the speed of digital transmission systems.

Bit Map : The total of all bit planes used to represent a graphic. Its size is measured in horizontal, vertical and depth of bits. In a one-bit (monochrome) system there is only one bit plane. As additional planes are added color can be described. Two bit planes yield four possible values per pixel, eight yield 256, and so on.

Bitnet. An academic and research computer network that stores and forwards messages sent between users. This system was a precursor to the Internet and its use today is limited.

Browser. Software that allows you to "surf " the Internet. Netscape, Mosaic, and Internet Explorer are examples of Web browsers. A browser provides an easy to use interface for accessing the information on the World Wide Web.

Broadband. The term applied to networks having bandwidths significantly greater than that found in telephony networks. Broadband systems are capable of carrying a large number of moving images or a vast quantity of data simultaneously. Broadband techniques usually depend on coaxial or optical cable for transmissions. They utilize multiplexing to permit the simultaneous operation of multiple channels or services on a single cable. Frequency division multiplexing or cell relay techniques can both be used in broadband transmission.  

Cache. Memory that holds copies of recently accessed data. Several Web browsers keep recently viewed pages in a cache so users can return to them quickly without suffering network delays.

Chat. Two or more individuals connected to Internet have real-time text-based conversations by typing messages into their computer. Groups gather to chat about various subjects. As you type, everything you type is displayed to the other members of the chat group.

Compact Disc (CD). High density storage media based on a 4.75" reflective optical disc. Can hold up to 650,000,000 bytes of data, that is equivalent to 12,000 images or 200,000 pages of text. CDs may all look the same, but there are numerous standards for different applications. The most common are defined below.

Compact Disc-Interactive (CD-I). Interactive multimedia platform developed for the consumer market by Philips. It is a proprietary version of the CD-ROM that delivers data, text, audio, stills, and video.

Compact Disc Read-Only Memory (CD-ROM). Version of the CD that allows the information to be stored and retrieved. Once a CD-ROM is pressed, new data cannot be stored and the disc cannot be erased for reuse. Although CD-ROMs look like music discs, they can only be used with a computer equipped with a CD-ROM drive.

Compact Disc Read-Write (CD-RW). CD-ROM recording systems can be used to read data from a compact disc, record data onto a compact disc, like any other recordable media, erase and re-record data. Most CD systems are now RW.

Compact Disc-Recordable (CD-R). CD-ROM recording systems can be used to record data onto a compact disc, recordable like any other recordable media. However, they cannot be erased and re-recorded. For large-scale duplication of CD-ROMs, a pressing facility is preferred.

Compressed Video. A digital transmission process used to transmit a video signal. When the vast amount of information in a video transmission is compressed into a fraction of its former bandwidth by a codec, the resulting compressed video can be transmitted more economically and through existing phone lines. While compressed video requires less bandwidth, signal quality may be reduced. As a result, picture quality is generally not as good as full-motion video. Quick motions often appear somewhat blurred. This quality issue is becoming less of a concern as more and more playback systems for compressed video run at 30 frames per second.

CGI- Common Gateway Interface, an Application Programming Interface (API) peculiar to the UNIX operating system which allows a Web server to pass data from an HTML document to a CGI script, which runs various programs as necessary and returns resulting data for display over the Web.

COM port- Serial ports on the IBM PC compatible computer, usually, but not always used for data communications, are referred to by system designators COM1, COM2, COM3...etc.

Desktop Publishing. Software programs that enable the user to use a microcomputer and a laser or color printer to produce relatively high-quality publications.

Digital Communication. A communications format used with both electronic and light-based space systems that transmits audio, video, and data as bits ("1s" and "0s") of information. Codecs are used to convert traditional analog signals to digital format and back again. Digital technology also allows communications signals to be compressed for more efficient transmission. See Analog Communication.

Domain. In the Internet, a part of a naming hierarchy consisting of a sequence of names (labels) seperated by periods (dots). e.g., brazosport.edu.

Downloading. A procedure for transferring or retrieving a file from a distant computer. Opposite of uploading. Many Web sites have links to files such that you can simply click on the link and your browser will handle the downloading of the file(s) to your computer.

DNS- Domain Name Service, a two-column lookup table system of matching mnemonic machine names to their numeric IP addresses. The tables are maintained at local, regional, and global levels by various organizations, making it easier for humans to find their way around the Internet or their LAN.

DSL. Digital Subscriber Line. A technology that exploits unused frequencies on copper telephone lines to transmit traffic typically at multi-megabit speeds. DSL can allow voice and high-speed data to be sent simultaneously over the same line. Because the service is 'always available,' end-users don't need to dial in or wait for call set-up.

Electronic Bulletin Boards. Information services that can be reached via computers connected by modem and/or Internet. With these services users can gather information, place and read electronic messages from other users, and download available files.

Electronic Mail. E-Mail. E-mail is a fast, easy, and inexpensive way to communicate with individuals or groups on networked computers and computers equipped for Internet access. Besides basic correspondence, with some systems you can attach and send documents and other files.

Ethernet : A LAN running on coaxial or twisted pair wiring, at 1 or 10 Mbps.

FTP. File Transfer Protocol. The standard for transferring files from one computer to another. Built into browsers for downloading files, special software such as WSFTP (Windows) or Fetch (Mac) is required for uploading files.

Fiber Optic Cable. Bundled glass rods (fibers) that are extremely thin and flexible and are capable of transmitting voice, video, and data signals in either analog or digital formats. This is accomplished with very little loss in signal quality. A single glass fiber can carry the equivalent of 100 channels of television or 100,000 telephone calls, with even more capacity possible by encasing many fibers within a cable.

Hard Drive (Hard Disk). A rigid non-removable disk in a computer and the drive that houses it. Hard disks store more data and can be accessed quicker than floppy disks.

Hertz (Hz) : The name given to the basic measure of radio frequency characteristics. An electromagnetic wave completes a full oscillation from its positive to its negative pole and back again in what is known as a cycle. A single Hertz is thus equal to one cycle per second.

Home Page- the top-level hypertext document in a collection of linked HTML documents, e.g. http://www.brazosport.edu is Brazosport College's home page. The home page links to lower level pages something like an organizational chart and would have extended addresses. Some lower sections may be set up as a unique web site with its own home page and other pages linked from that, e.g. www.brazosport.edu/~distance/.

Hub : A network's or system's signal distribution point where multiple circuits convene and are connected. Some type of switching or information transfer can then take place. Switching hubs can also be used in Ethernet LAN environments is an arrangement whereby a LAN segment might support only one workstation. This relieves congestion through a process called micro-segmenting.

Hypertext. Text with links to other text. Documents written as hypertext contain text that when "clicked on" by the user with a mouse, links to other documents.

HyperText Markup Language (HTML). Set of programming commands inserted around blocks of text that describe how to display it. HTML commands also display other media (graphics, sound, and video). Documents on the Web are often written in HTML.

Integrated Services Digital Network (ISDN). Digital network with higher speed than found on the traditional telephone network. Even though ISDN uses existing phone lines, it does require specialized equipment. Because the network is all digital it can easily send voice, data, and video over the same line simultaneously.

Internet. A worldwide network of computer networks. It is an interconnection of large and small networks around the globe. The Internet began in 1962 as a resilient computer network for the U.S. military and over time has grown into a global communication tool of more than 12,000 computer networks that share a common addressing scheme.

Intranet. Inter-connected network within one organization that uses Web technologies for the sharing of information internally, not world wide. Such information might include organization policies and procedures, announcements, or information about new products.

IP Address: The number assigned to a computer, fixed or floating, that allows it to connect to a network.

ISP- Internet Service Provider, a reseller of internet access services.

Java. Programming language developed by Sun Microsystems that creates code for interactive applications that is executable on web pages by web browsers. These Java applications can execute on any platform--Mac, PC, etc.

JPEG (Joint Picture Expert Group). Standard for the compression of still pictures, such as those that might be used on a Web site.

LAN (Local Area Network). Communications network connecting computers by wire, cable, or fiber optics link. Usually serves parts of an organization located close to one another, generally in the same building or within 2 miles of one another. Allows users to share software, hardware and data.

Links or Hyperlinks. A graphic, line of text, or both on a Web page that connects to another page on the same Web site or to one on a Web server located anywhere in the world. Links are "clicked on" to go to the Web page they specify.

Mainframe Computer. A large relatively complex computer. Its capacity far exceeds that of the microcomputer.

Microcomputer. A computer with a microprocessor chip-based processing unit. Microcomputers are the original personal computers that many people use at home and at work.

Modem. Equipment that converts digital signals into analog signals for purpose of transmission over a telephone line. Signal is then converted back to digital form so that it can be processed by a receiving computer. Modems are typically used to link computers via telephone lines. Short for modulator-demodulator. Typical modems for home use are 14.4 kbps. 14 kilobytes per second translates into a transmission or receiving rate of approximately 1600 bytes per second.

MPEG. Moving Picture Experts Group. The standard for compression and storage of motion video, for example, videos available though the World Wide Web.

Network. A group of stations (computers, telephones, or other devices) connected by communications facilities for exchanging information. Connection can be permanent, via cable, or temporary, through telephone or other communications links. The transmission medium can be physical (copper, wire, fiber optic cable, etc.) or wireless, for example via satellite.

Node. An origination or reception site on a network or a concentration point in a network where numerous trunks come together at the same switch.

Pixel. The smallest element of the computer or television display on the raster scale.

Server. Computer that can be accessed for information through an internal or external network. This computer "serves up" the requested information if the requester has appropriate access. Web servers can usually be access by anyone on the network for web pages though there may be some restrictions which require a user name and password.

Shareware. Computer software developed for the public domain, which can be used or copied without infringing copyright. Programmers typically get paid a small one time fee from users who find the software useful.

TCP/IP- Transmission Control Program/Internet Protocol. The basic packet protocol used to connect machines globally on the Internet is referred to as the Internet Protocol or IP. The Transmission Control Protocol (TCP) interacts with IP to provide an application protocol interface. The term has come to generically refer to a family of protocols used to connect local area networks to one another, forming an internet, and more specifically the global  Internet.

TELNET- an application program that allows users to interactively logon to menued services provided at an Internet sites.

Touch Screen. Input device over the television or a special computer screen that is used to simplify user input and response. The user touches the screen rather than a keyboard, keypad, or mouse to control the output. Touch screens work best with menus or multiple-choice decision points, and also allow some simulation of hands-on training, i.e. pointing to parts of a body.

Uploading. The transfer of copies of a file from the user's own computer to a remote database or other computer. The reverse of downloading. This usually requires an ftp program and access via user name and password to the remote computer.

URLs (Uniform Resource Locators). The address system used by the Internet to locate resources such as web sites. An URL includes the type of resource being accessed such as gopher or hypertext), the address of the server, and the location of the file e.g.  http://www.brazosport.edu/~distance/index.html is Brazosport College's URL. "http://" indicates the access method as Hyper Text Transfer Protocol. "www.brazosport.edu" is the address of the server. "/~distance/" specifies the directory the file is located. "index.html" is the initial page of the distance learning web site. Web browsers will assume "http://" and "index.html", so you can simply use www.brazosport.edu/~distance/ as the URL.

User Name. A name used to access a computer or network usually associated with a specific password. Most are case sensitive and without the correct name and password, access will be denied. If anyone else gets a user's name and password, they may have access to the files (work) on that computer.

USENET. Users Network, one of the earliest networks of computers which exchange e-mail conferences via the Internet using UUCP and NNTP. Properly capitalized in full but often rendered as "Usenet."

WAN. Wide Area Network. A communications network that services a geographic area larger than that served by a local area network or metropolitan area network. WANs include commercial or educational dial-up networks such as CompuServe, InterNet and BITNET.

Web-casting. see Streaming Media..

Web-site. Related collection of web documents. The address for a web site (see URL) takes you to the initial page, or home page. From the home page you can go to all the other pages on the web site.

World Wide Web (WWW). (world wide wait) A hypertext-based, distributed information system originally created by researchers at CERN, the European Laboratory for Particle Physics, to facilitate sharing research information. The Web presents the user with documents, called web pages, full of links to other documents or information systems. Selecting one of these links, the user can access more information about a particular topic. Web pages include text as well as multimedia (images, video, animation, sound). Servers are connected to the Internet to allow users to traverse (or "surf") the Web using a Web browser. In addition, many other resource formats such as Gopher are accessible by Web browsers.
 
 

Analog-to-Digital Conversion (ADC) : Process of converting analog signals to a digital representation. DAC represents the reverse translation.

Asynchronous Transfer Mode (ATM). Communication technology that uses high-bandwidth, low-delay transport technology, and multiplexing techniques. Through dedicated media connections it provides simultaneous transport of voice, video, and data signals more than 50 times faster than current technology. May be used in phone and computer networks of the future.

Audio Bridge. Specialized equipment that interconnects three or more telephone lines (usually operator assisted) to enable conference calls. The audioconferencing equipment needed to connect multiple sites can be provided by companies specializing in bridge services.

Bps: Bits per second, a unit of measurement of the speed of data transmission and thus of bandwidth.

B channel : The ISDN circuit-switched bearer channels, capable of transmitting 64 Kbps of digitized information.

B-Mac : A method of transmitting and scrambling television signals. In such transmissions MAC (Multiplexed Analog Component) signals are time-multiplexed with a digital burst containing digitized sound, video synchronizing, authorization, and information.

Bandwidth: A measure of spectrum (frequency) use or capacity. For instance, a voice transmission by telephone requires a bandwidth of about 3000 cycles per second (3KHz). A TV channel occupies a bandwidth of 6 million cycles per second (6 MHz) in terrestrial Systems. In videoconference based systems a larger bandwidth of 17.5 to 72 MHz is used to spread or "dither" the television signal in order to prevent interference.

Baseband : The basic direct output signal in an intermediate frequency based obtained directly from a television camera, videoconference television receiver, or video tape recorder. Baseband signals can be viewed only on studio monitors. To display the baseband signal on a conventional television set a "modulator" is required to convert the baseband signal to one of the VHF or UHF television channels which the television set can be tuned to receive.

Baud : The rate of data transmission based on the number of signal elements or symbols transmitted per second. Today most digital signals are characterized in bits per second.

Bit Error Rate : The fraction of a sequence of message bits that are in error. A bit error rate of 10-6 means that there is an average of one error per million bits.

Bit Rate. The speed of a digital transmission, measured in bits per second.

Blanking. An ordinary television signal consists of 30 separate still pictures or frames sent every second. They occur so rapidly, the human eye blurs them together to form an illusion of moving pictures. This is the basis for television and motion picture systems. The blanking interval is that portion of the television signal which occurs after one picture frame is sent and before the next one is transmitted. During this period of time special data signals can be sent which will not be picked up on an ordinary television receiver.

BRI. See the ISDN entry.

Bridge. In videoconferencing vernacular, a bridge connects three or more conference sites so that they can simultaneously communicate. Bridges are often called MCU's - multipoint conferencing units. In IEEE 802 parlance, a bridge is a device that interconnects LAN's or LAN segments at the data-link layer of the OSI model to extend the LAN environment physically. They work with frames (as opposed to packets) of data, forwarding them between networks. They learn station addresses and they resolve problems with loops in the topology by participating in the spanning tree algorithm. Finally, the term bridge can be used in audio conferencing to refer to a device that connects multiple (more than two) voice calls so that all participants can hear and be heard.

Broadband. The term applied to networks having bandwidths significantly greater than that found in telephony networks. Broadband systems are capable of carrying a large number of moving images or a vast quantity of data simultaneously. Broadband techniques usually depend on coaxial or optical cable for transmissions. They utilize multiplexing to permit the simultaneous operation of multiple channels or services on a single cable. Frequency division multiplexing or cell relay techniques can both be used in broadband transmission.

Broadcast : A packet delivery system where a copy of given packet is given to all hosts attached to the network. Example: Ethernet.

Brouter : Concatenation of "bridge" and "router". Used to refer to devices which perform both bridging and routing functions.

Burtsy data : Information which flows in short intense data groupings (often packets) with relative long silent periods between each transmission burst.

Carrier : A term used to refer to various telephone companies that provide local, long distance or value added services; alternately, a system or systems whereby many channels of electrical information can be carried over a single transmission path.

C-band. A type of satellite transmission with less path loss than other satellite standards such as Ku-band. C-band, however, requires a relatively large antenna. C-band frequencies are shared with terrestrial microwave transmissions, which can cause interference with weaker satellite signals in certain areas.

CCD : Charge coupled device used in cameras as an optical scanning mechanism. It consists of a shift register that stores samples of analog signals. An analog charge is sequentially passed along the device by the action of stepping voltages and stored in potential wells formed under electrodes. The charge is moved from one well to another by the stepping voltages.

CCITT : Consultative Committee for International Telegraphy and Telephoney, (now called the International Telecommunications Union's Telecommunications Standardization Sector or TSS) An international body responsible for establishing interoperability standards for communications systems. The world's leading telecommunications standards organization.

CIF : Common Intermediate Format, an international standard for video display formats developed by TSS. The QCIF format, which employs half the CIF spatial resolution in both horizontal and verticle directions, is the mandatory H.261 format. QCIF is used for most desktop videoconferencing applications where head and shoulder pictures are sent from desk to desk. QCIF displays 176 pixels grouped in 144 non-interlaced luminance lines.

Codec. Coder/decoder equipment used to convert and compress analog video and audio signals into a digital format for transmission, then convert them back to analog signals upon reaching their destination.

Compression : The process of reducing the information content of a signal so that it occupies less space on a transmission channel or storage device and a fundamental concept of video communications. An uncompressed NTSC signal requires about 90 Mbps of throughput, greatly exceeding the speed of all but the fastest and shortest of today's networks. Squeezing the video information can be accomplished by reducing the quality (sending fewer frames in a second or displaying the information in a smaller window) or by eliminating redundancy.

Conus : Contiguous United States. In short, all the states in the U.S. except Hawaii and Alaska. This term is used to describe the coverage of a satellite signal.

D-channel : In an ISDN network the D-channel is a signaling channel over which packet-switched information is passed by the carrier. The D-channel can also support the transmission of low-speed data or telemetry sent by the subscriber.

Data compression : Reducing the size of a data file by reducing unnecessary information, such as blanks and repeating or redundant characters or patterns.

DBS : Direct broadcast videoconference. Refers to service that uses videoconferences to broadcast multiple channels of television programming directly to home mounted small-dish antennas.

Decoder : A television set-top device which enables the home subscriber to convert an electronically scrambled television picture into a viewable signal. This should not be confused with a digital coder/decoder known as a CODEC which is used in conjunction with digital transmissions.

Delay : The time it takes for a signal to go from the sending station through the videoconference to the receiving station. This transmission delay for a single hop videoconference connection is very close on one-quarter of a second.

Demodulator : A videoconference receiver circuit which extracts or "demodulates" the "wanted "signals from the received carrier.

Digital : Conversion of information into bits of data for transmission through wire, fiber optic cable, videoconference, or over air techniques. Method allows simultaneous transmission of voice, data or video.

Digital Speech Interpolation : DSI - A means of transmitting telephony. Two and One half to three times more efficiently based on the principle that people are talking only about 40% of the time.

Dish. An earthbound dish-shaped antenna used for receiving satellite signals. Also referred to as downlink dish and ground receiving dish.

Duplex Video. Two-way video communication capable of simultaneous origination and reception.

DVB : Digital Video Broadcast, the standard for direct broadcast television in Europe and the U.S. Based on MPEG2 Compression.

Earth Station. A ground-placed antenna used to transmit or receive signals to or from satellites, typically located in geostationary orbit.

Echo Canceller : An electronic circuit which attenuates or eliminates the echo effect on videoconference telephony links. Echo cancellers are largely replacing obsolete echo suppressors.

Echo Effect : A time-delayed electronic reflection of a speaker's voice. This is largely eliminated by modern digital echo cancellers.

Echo suppression : Used to reduce annoying echoes in the audio portion of a videoconference. An echo suppressor is a voice-activated "on/off" switch that is connected to the four-wire side of a circuit. It silences all sound when it is on by temporarily deadening the communication link in one direction. Unfortunately, not only the echo is stopped but also the remote end's new speech, which results in clipping.

EIRP : Effective Isotropic Radiated Power - This term describes the strength of the signal leaving the videoconference antenna or the transmitting earth station antenna, and is used in determining the C/N and S/N. The transmit power value in units of dBW is expressed by the product of the transponder output power and the gain of the videoconference transmit antenna.

Encoder : A device used to electronically alter a signal so that it can only be viewed on a receiver equipped with a special decoder.

Footprint. The area of the earth's surface where a particular satellite's signal can be received. A footprint can cover one-third of the globe, but is usually less.

Fps : Frames per second.

Fractional T-1 : FT-1 or fractional T-1 refers to any data transmission rate between 56 Kbps and 1.544 Mbps. It is typically provided by a carrier in lieu of a full T-1 connection and is a point-to-point arrangement. A specialized multiplexer is used by the customer to channelize the carrier's signals.

Frame rate. Frequency with which video frames are displayed on a monitor, typically described in frames-per-second (fps). Higher frame rates improve the appearance of video motion. Broadcast TV (full-motion video) is 30 frames-per-second.

Full-Motion Video. Equivalent to broadcast television video with a frame rate of 30 fps. Images are sent in real time and motion is continuous. Unlike compressed video signals (which tend to be blurry), full-motion video refers to high-quality signals, similar to what is received over a television set.

Geostationary Orbit. An earth orbit located directly above the equator, approximately 22,300 miles above the surface. Satellites in this orbit rotate at the same relative speed as the earth itself. This allows earth antennas to remain fixed.

H.320 Standard. A widely-used video compression standard that allows a wide variety of videoconferencing systems to communicate. H.320 includes a number of individual recommendations for coding, framing, signaling, and establishing connections.

H.323 Standard. A video compression standard that allows a wide variety of videoconferencing systems to connect and communicate using digital networks and internet protocals (IP)..

High Definition TV (HDTV). Regular NTSC signals have 525 lines of resolution. HDTV has 1125 lines of resolution having over five times the video information than that of a conventional NTSC-type TV set. In spite of its obvious advantages, transmission requires extraordinary bandwidth of five times the capacity of a conventional TV signal. TV receivers are estimated to be 30% more expensive than today's most costly sets.

Instructional Television Fixed Services (ITFS). A band of low-power microwave frequencies set aside by the Federal Communications Commission (FCC) exclusively for the transmission of educational programming, and licensed to public institutions. ITFS is typically used in urban areas and requires a specialized antenna. Receiving sites require a converter capable of changing signals to those used by a standard television set.

ISDN - Integrated Services Digital Network. : A CCITT standard for integrated transmission of  voice, video and data. Bandwidths include: Basic Rate Interface - BRI (144 Kbps - 2 B & 1 D channel) and Primary Rate Interface - PRI (1.544 and 2.048 Mbps). A set of protocol and interface standards that effectively constitute an integrated (voice, video, and data) telephone "network." These standards promote global availability and compatibility of ISDN products and services. The two types of ISDN discussed in this Guide are Basic Rate Interface (BRI) and Primate Rate Interface (PRI). ISDN BRI  is the interface to connect the desktop to the digital long distance network. ISDN BRI provides two 64Kbps B ("bearer") channels to carry information content, the voice, video, and data substance of a transmission. A separate 16Kbps D ("data") channel is used for call setup and signaling. ISDN BRI is often called "2B+D" ISDN, for its combination of two B and one D channel. This service is marketed and supported by the LECs. ISDN PRI (Primary Rate Interface) is the ISDN equivalent of a T-1 circuit. It provides 23B+D (in North America) or 30B+D (in Europe) running at 1.544 Mbps and 2.048Mps, respectively. Each channel (time slot) is 64Kbps. One channel is reserved as the D channel; the other 23, as bearer channels (23+D).

Ku-band. Most popular type of satellite transmission for uplinking and downlinking. Ku-band operates on a higher frequency than C-band transmissions and requires smaller antennas.

Microwave. High-frequency radio waves used for point-to-point and omnidirectional communication of audio, data, and video signals. Microwave frequencies require direct line of sight to operate. Obstructions in the path usually distort or block the signal. Growth of fiber optic networks have tended to curtail the growth and use of microwave relays.

Modulation. The process of manipulating the frequency or amplitude of a carrier in relation to an incoming video, voice or data signal.

Modulator. A device which modulates a carrier. Modulators are found as components in broadcasting transmitters and in videoconference transponders. Modulators are also used by CATV companies to place a baseband video television signal onto a desired VHF or UHF channel. Home video tape recorders also have built-in modulators which enable the recorded video information to be played back using a television receiver tuned to VHF channel 3 or 4.

Multiplex. The act of combining input signals from many sources onto a single communications path, or the use of a single path for transmitting signals from several sources. Advantages of multiplexing is that it doubles the capacity of television transmission and allows for simultaneous feed of independent programs for two audiences.

Multipoint. Communication configuration in which several terminals or stations are connected. Compare to point-to-point, where communication is between two stations only.

Multi-point videoconference. A video conference with 3 or more sites. Sites must connect via a video bridge.

Multipoint Control Unit. (MCU) A device that bridges together multiple inputs so that more than three parties can participate in a video conference. The MCU uses fast switching techniques to patch the presenters or speaker's input to the output ports representing the other participants.

Noise. Any unwanted and unmodulated energy that is always present to some extent within any signal.

NT 1. Network Termination type 1. The NT-1 is a device which converts the two-wire line (or "U" interface) coming from your telephone company into a 4-wire line (or "S/T" interface). The NT- 1 is physically connected between the ISDN board of your videoconferencing system and your ISDN phone line. The NT- 1 supports network maintenance functions such as loop testing. Check to see if your ISDN equipment requires an external NT-1 to operate.

NTSC - National Television Standards Committee (Never Twice the Same Color). A video standard established by the United States (RCA/NBC} and adopted by numerous other countries. This is a 525-line video with 3.58-MHz chroma subcarrier and 60 cycles per second. Frames are displayed at 30 frames per second.

Packet Switching. Data transmission method that divides messages into standard-sized packets for greater efficiency of routing and transport through a network.

PAL - Phase Alternative Line System. The European TV standard based upon 50 cycles.per second electrical system and 625 lines per frame and 25 Frames per Second. (NTSC, the North American standard is based on 30 frames per second) (French use SECAM)

Pan. To pivot a camera in a horizontal direction, tilt is to pivot in the vertical direction.

PBX. Private Branch Exchange. A telephone switch, usually located on a customer's premises, connected to the telephone network but operated by the customer. A PBX provides pooled access to a given number of inside (extension) lines in a smaller number of outside lines (trunks). Often, outgoing calls are dialed directly, incoming calls are handled by an operator or switched automatically by the PBX software.

POTS. Plain Old Telephone Service. Conventional analog telephone lines using twisted-pair copper wire. This is used to provide residential service.

PRI. See ISDN.

Originating Site. The site initiating the conference or meeting that is to be distributed simultaneously with technology such as audioconferencing or videoconferencing.

Rain Outage. Loss of signal at Ku-band satellite frequencies due to absorption and increased sky noise caused by rainfall or ice crystals in the upper atmosphere.

Resolution. The clarity of the image on video display screen. Three factors influence resolution: lines of resolution (vertical and horizontal), raster scan rate (number of times per second the image on a video screen can be refreshed or "lit up" again), and bandwidth.

RGB. Video display screen with colors Red, Green, Blue as light waves. The three colors combined in different ways produce all other colors.

Satellite. An earth-orbiting device used for receiving and transmitting signals. Each satellite has a number of transponders which receive the signal and bounce it back to earth, where it is received by any of the dish-shaped earth stations, then transmitted via cable, phone lines, or microwave to its final receiver TV set.

Signal to Noise Ratio (S/N). The ratio of the signal power and noise power. A video S/N of 54 to 56 dB is considered to be an excellent S/N, that is, of broadcast quality. A video S/N of 48 to 52 dB is considered to be a good S/N at the headend for Cable TV.

Splitte. A passive device (one with no active electronic components) which distributes a television signal carried on a cable in two or more paths and sends it to a number of receivers simultaneously.

Solar Outage. Solar outages occur when an antenna is looking at a satellite, and the sun passes behind or near the satellite and within the field of view of the antenna. The field of view is usually wider than the beamwidth. Solar outages can be exactly predicted as to the timing of each site.

Switched Network. A type of system in which each user has a unique address (such as a phone number) that allows the network to connect any two points directly.

T1. The transmission bit rate of 1.544 millions bits per second. This is also equivalent to the ISDN Primary Rate Interface for the U.S. The European T1 or E1 transmission rate is 2.048 million bits per second.

Touch Screen. Input device over the television or a special computer screen that is used to simplify user input and response. The user touches the screen rather than a keyboard, keypad, or mouse to control the output. Touch screens work best with menus or multiple-choice decision points, and also allow some simulation of hands-on training, i.e. pointing to parts of a body.

Transmitter. An electronic device consisting of oscillator, modulator and other circuits which produce a radio or television electromagnetic wave signal for radiation into the atmosphere by an antenna.

Transponder. A combination receiver, frequency converter, and transmitter package, physically part of a communications satellite. Transponders have a typical output of five to ten watts, operate over a frequency band with a 36 to 72 megahertz bandwidth in the L, C, Ku bands. Communications satellites typically have between 12 and 24 onboard transponders although the INTELSAT VI at the extreme end has 50.

Uplink/Downlink. Programs are "uplinked" to the satellite transponder and "downlinked" to the ground receiving dish.

Video Bridge. Specialized equipment that permits three locations or more to be joined together in a videoconferenc

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