Internet TV with CU-SeeMe: Appendix C - Glossary

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1. Introduction

2. Usage

3. Internet

4. Hardware

5. Software

6. User's Guide

7. Reflectors

8. History

9. Other

10. Future

A. Trouble- shooting

B. Operator's Guide

C. Glossary

D. Bibliography


Internet TV with CU-SeeMe: Appendix C - Glossary

Appendix C

Glossary of Terms

I've created this glossary by looking through the questions asked by new CU-SeeMe users; the words and acronyms they asked about appear here. If you still can't find what you're looking for, look in the index, on my web pages, or ask the readers of the CU-SeeMe Discussion list.

ARPA - Advanced Research Projects Agency. Their machinations caused the ARPANET (cf) to be created.

Analog - A method of transferring data by changes in signal strength. Frequency modulation (FM) and amplitude modulation (AM) are examples of analog information.

ARPANET - ARPA Network. An early collection of computers that evolved into the Internet.

Audio - Sound. The portion of a conversation that is interpreted by the ears. The other portion is the video (cf).

Auxiliary Data Function Modules - A programmatic interface that allows for the extention of CU-SeeMe's core capabilities. Developed by Aaron Giles. Also known as AuxData. The Talk Window Function Module and the Slide Window Function Module are two examples of extentions to CU-SeeMe.

Bandwidth - the carrying capacity of a particular connection medium, measured in bits per second (bps).

BRI - Basic Rate Interface. The standard configuration of home-based ISDN (cf), defined as two 64 kbps Bearer channels (cf) and one coordinating 16 kbps Data channel (cf), BRI is also known as a 2B+D connection.

Baud rate - an obsolete term used for discussing bandwidth (cf). Refers specifically to the state changes in the modem (cf), not to the amount of data that could be transferred. The current term is bits per second, or bps.

Bearer channels - also known as B channels, these are the high-speed portion used in ISDN (cf). See also Data channels.

BITNET - Because It's Time NETwork.

BOOTP - Boot Protocol. A system whereby a computer on a network gets its configuration information from a BOOTP server on the network. A predecessor to DHCP (cf), BOOTP is a great help to system/network administrators.

Broadcast - the generic term for sharing an event via CU-SeeMe, NV (cf), or VAT (cf). The use of this term generates some controversy and worry in the CU-SeeMe community because there's great federal regulation of traditional broadcasters and no regulation over the contents of the Internet.

CCD - Charge-Coupled Device. Part of a camera that converts the (analog) light into (digital) signals sent to a computer, where scene-processing (and perhaps transmission) takes place.

CCITT - Consultive Committee for International Telephone and Telegraph. A standards-setting body, it's been renamed to the Telecommunications Standards Bureau of the International Telecommunications Union, leading to the unwieldy acronym CCITT/ITU-TSB. (No, I'm not kidding.)

Client - end-user software that interacts with a server (cf) elsewhere on the network. The CU-SeeMe client is the software run on Macintosh, Windows, or Amiga computers that allow one end-user to interact with others. The CU-SeeMe reflector software is the server end of the transaction; it coordinates the activities of the clients.

CIX - Commercial Internet Exchange. While the Internet disallowed commercial traffic (cf) the CIX was a for-profit alternative.

Compression - the conversion of data into a smaller package. Compression is very important when bandwidth (cf) is low, because it's the only way to obtain enough data. Aggressive compression usually requires faster computers.

Cornell University - the home of CU-SeeMe. Located on the banks of the Finger Lakes, near the town of Ithaca, New York.

Costware - software that is sold commercially. Contrast with shareware (cf) and freeware (cf).

Data channel - the low-bandwidth (cf) portion of ISDN (cf). Also known as the D channel, it's used to carry call set-up, coordination, synchonization, and signalling data; things we, the users, never see.

Decompression - the process used to extract data that was previously compressed (cf).

DHCP - Dynamic Host Configuration Protocol. A more advanced successor to BOOTP (cf), DHCP provides configuration information to computers on a network.

Digital - information transmitted in discrete units, as opposed to analog (cf) methods. The best-known digital processors are personal computers.

Digital switching system - The hardware in your telephone provider's central office that's used for servicing home-based ISDN (cf) connections.

Digitizer - hardware that converts analog (cf) signals to digital (cf) signals. Most typically used allow consumer video cameras to provide data to personal computers.

Domain - the collective name for a group of people on a network. Typical domain names include,,,, and

DNS - Domain Name System. A method for converting easy-to-read machine names (such as into the numeric network addresses used by computers (such as

Encoding - the complementary operation to decoding (cf).

Error correction - the capability to detect and overcome errors in data transmission. The use of software error correction, such as TCP/IP, obviates the need for hardware error correction, such as is provided by some modems.

Ethernet - one of several types of physical wiring systems that result in a 10 mbps network.

FAQ - Frequently Asked Questions. Document, usually compiled by volunteers, that contains frequently asked questions about some topic and their answers.

Freeware - software that is given away without the expectation of remuneration. Contrast with shareware (cf) and costware (cf).

FTP - File Transfer Protocol. A widely-available standard method for transferring files (text documents, images, sounds, movies, and the like) between computers.

Full-duplex - a communications connection that allows participants to send and receive simultaneously (like a telephone). All Macintoshes are full-duplex. Compare to half-duplex (cf).

Gateway - the network device between your local network and the outside world. Often ignored in older communication schemes, the identity of the gateway is required by modern systems such as Apple's Open Transport.

Greyscale - An method of representing an image in varying shades of grey.

GSN - Global SchoolNet.

Half-duplex - a communications connection that requires the participants choose between sending and receiving (as in a walkie-talkie). Most standard Intel-based PCs are half-duplex. Compare to full-duplex (cf).

Hardware Handshaking - the use of a cable to toggle flow control on 14.4 kbps and faster modems. Slower modems typically use software flow control, also known as XON/XOFF.

HDTV - High-Definition television. Any one of several systems of new television hardware and changes in broadcast software that results in more detailed images.

Hostname - administrative name of a particular computer, required for identifying machines on a network.

Internet - a global network consisting of many national and regional networks.

IAB - Internet Architecture Board. The body that sets the communication standards for software and hardware systems that comprise the Internet.

IETF - Internet Engineering Task Force. A public forum dedicated to discussing and handling technical problems facing the Internet.

Inverse multiplexing - The combining of one or more ISDN (cf) bearer channels (cf). Also known as bonding.

IP - Internet Protocol. One of the standard communications systems for computers connected to the Internet.

IP address - a unique numeric identifer of a network-connected computer.

IRTF - Internet Research Task Force. The body that handles issues that likely will affect the Internet in the next decade.

ISOC - Internet Society.

ISDN - Integrated Services Digital Network. A high-bandwidth (cf) network connection method, popular for connecting homes to the Internet or a corporate local area network. See also BRI, PRI, and inverse multiplexing.

KB - One kilobit is 1024 bits.

Local Area Networks - Two or more computers physically connected with short bits of wire.

Manual addressing - the practice of assigning a fixed (or "static") IP address (cf) to a computer on a network. Compare to server-based addressing.

Maven - audioconferencing tool written by Charlie Kline. Before Maven was incorporated into CU-SeeMe to provide audio capability, it was used in tandem with CU-SeeMe. Charlie contines to upgrade Maven, and has recently added even more audio encoding features.

MB - a megabit is 1024 x 1024 bits, or 1024 kilobits.

MOTD - Message of the Day. A greeting that informs users of current status, upcoming events, contact persons, and the like.

MTU/MRU - maximum transmit unit/maximum receive unit. Specifications for the largest packet of information that may be sent or received over a particular network connection. Typical numbers for MTU are 1006 (SLIP) and 296 (CSLIP); MRU is 1500 for PPP.

Nameserver - one or more computers on a network that provide Domain Name Services (cf).

NASA - National Aeronautics and Space Administration.

NASA Select TV - around-the-clock broadcast of shuttle missions, press conferences, educational films, and other space-related programming.

NT1 - Network Termination Device. Used in ISDN (cf) network connections, this device sits between the telephone company's digital switching service and your local ISDN network.

NNTP - Network News Transfer Protocol. Method for obtaining USENET newsgroups over TCP/IP networks.

NREN - National Research and Education Network.

NSF - National Science Foundation.

NTSC - National Television System Committee. A video transmission standard used in the USA.

PAL - Phase Alternation by Line. A video transmission standard used in much of Europe, Africa, the Middle East, and Far East. PAL uses color images at 625 horizontal lines of resolution (except in Brazil, where PAL-M is used and supports 30 FPS with 525 horizontal lines of resolution).

Plug-ins - see Auxiliary Data Function Modules.

PPP - Point-to-Point Protocol. A popular connection method for modem-based Internet users.

PRI - Primary Rate Interface. A high-bandwidth (cf) network connection common in larger organizations (due to its greater capacity and cost). PRI configuration varies geographically. In the United States a PRI connection is defined as 23 64 kbps Bearer channels (cf) and one coordinating 64 kbps Data channel (cf). PRI is also known as a 23B+D connection. With a total carrying capacity of 1.544 mbps, a PRI is transmitted through a standard North American T-1 line (which may physically be nothing more than one twisted-pair copper wire).

Reflector - software that allows CU-SeeMe users to hold multi-party conferences.

SECAM - Systeme Electronique Couleur Avec Memoire. A video transmission standard used in throughout the world, in the former USSR, and in areas of French influence. SECAM uses color images of 625 lines of resolution at 25 frames per second.

Server-based addressing - the practice of assigning an IP address (cf) from a pool of addresses when a computer makes itself known to the network. Also known as "dynamic" addressing (as opposed to fixed addressing).

Shareware - software that given away with the expectation that a user will pay a nominal fee once an evaluation period is over. Contrast with freeware (cf) and costware (cf).

SLIP - Serial Line Internet Protocol. A popular connection method for modem-based Internet users.

SMTP - Simple Mail Transport Protocol. A standardized method for sending electronic mail to a network.

Sneakernet - tongue-in-cheek term for manually walking floppy diskettes between computers. What you use when the real network stops working.

Spam - the indiscriminate flooding of USENET newsgroups, typically with commercial solicitations.


Talk Function Module

TCP - Transmission Control Protocol.

Traffic - data being sent over a network.

Twisted-pair - simple two-strand copper wire used for local area networks and ISDN (cf).

DOD - U.S. Department of Defense. See ARPA.

UNIX - very popular computer operating system developed at Bell Laboratories.

URL - Uniform Resource Locator. Method for describing the location of information on the Internet.

USENET - User's Network. A collection of discussion topics that are broadcast worldwide via the Internet.

WAN - Wide Area Network. Computers connected over a large area. Compare with LAN.

Have you found errors nontrivial or marginal, factual, analytical and illogical, arithmetical, temporal, or even typographical? Please let me know; drop me email. Thanks!

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