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10BaseT - The IEEE standard using twisted pair cabling for networking computers at 10 Mbps (megabits per second). A successor to Ethernet, it is often mistaken as Ethernet. Although very similar, there are some differences between the two standards.

100BaseVG - A newer standard compatible with 10BaseT cabling networks, developed to increase data speeds up to 100 Mbps.

Application Software - Any software program used for producing or editing documents, drawings, presentations, graphics, spreadsheets, or used for managing information. Examples would be word processors, database programs, spreadsheet, etc.

Appletalk - A peer to peer network protocol designed by Apple Computers. It runs at a speed of 230 Kbps and is built into every Macintosh computer.

Analog Signal - A continuous electrical signal that is produced and transmitted in real time. (see Digital Signal)

ANSI/EIA/TIA/IEEE - Some of the more notable telecommunication industry associations that provide standards for how cabling networks are designed, manufactured and installed. The acronyms are as follows:

ANSI -- American National Standards Institute
EIA -- Electronic Industries Association
TIA -- Telecommunication Industry Association
IEEE -- International Electrical and Electronics Engineers

ATM - Asynchronous Transfer Mode - A switched data networking technology that allows data to be transmitted in standard sized cells, asynchronously. Asynchronously means that a computer can send a cell of data onto a network instantaneously without having to synchronize with the receiving computer. The actual speed of an ATM network is dependant upon the physical medium it is connected to. The most common speed today is 155 Mbps across a twisted pair cable, however, ATM can travel across anything from a 1.544 Mbps T1 circuit, up to a 622 Mbps OC-12 SONET circuit.

Bandwidth - The amount of frequency or "space" available (or needed) to transmit a signal. Bandwidth is measured in Hz (hertz). e.g. A standard TV channel requires 6 mHz (6,000,000 hertz) of bandwidth -- a cable having 600 mHz of bandwidth theoretically could carry 100 TV channels.

Baseband - 1. A basic analog or digital signal. 2. A widely used transmission technology where a single cable or medium is used to transmit only one signal at a time.

Bit - A single character or piece of information.

Bridge - A device that connects two or more networks together. (see gateway and router)

Broadband - A single cable or medium used for carrying several voice, video, and data signals by placing them at different frequencies. Cable TV is the most common example of using broadband technology.

Byte - A group of bits assembled to represent one piece of information. A byte made up of eight bits is common in computers, although a byte can be any number of bits.

CODEC - Coder/Decoder - Interface device used to transmit and receive signals across a digital circuit.

Concentrator - A device allowing several users to access and use individual data sources or channels on a network. A multiport device for connecting several users to a single source. Sometimes referred to as a hub.

Digital Signal - A signal that is transmitted as a series of numbers. This allows the receiving device to sort out the numbers, rejecting the noise which may have been added by the transmission, and receiving only the desired signal which results in a cleaner, truer signal. (See Analog Signal)

DVI - Digital Video Interactive - A video compression standard used for creating, editing, controlling, storing, and playing video in a digital format on a personal computer.

Ethernet - A common baseband networking protocol developed in the early 1980's. Originally developed to operate at 1 Mbps, today's Ethernet networks operate at 10 Mbps. Ethernet is still common among today's networks and is being developed for higher speeds.

FastEthernet - A competitor to the 100BaseVG standard. Based on Ethernet it is designed to operate at 100 Mbps.

FDDI - Fiber Distributed Data Interface - A standard written for fiber optics networking. FDDI uses a token passing protocol and can achieve data transfer speeds up to 100 Mbps. Under development is the the FDDI-II standard which will increase the speed up 200 Mbps.

Fiber Optics - A technology using glass fibers to transmit information in the form of light waves. Fiber Optic cable is commonly used to connect buildings together or where distances prohibit the use of copper in large data networks.

FOIRL - Fiber Optic Inter Repeater Link - An IEEE standard for connecting two repeaters with a fiber optic link. It is the original IEEE standard for using fiber optics in Ethernet type networks. There are now new IEEE standards for using fiber optics in data networks. Derived from the FOIRL standard, new standards include 10BaseFL, 10BaseFB, and 10BaseFP, all collectively known as 10BaseF.

Frequency - For measuring or generating radio signals, electrical signals, or sound waves. Frequency is measured in hertz, or cycles per second. Radio broadcasters use different frequencies to avoid interfering with one another.

Gateway - A device or computer connecting two or more dissimilar data networks. A gateway acts as an interpreter between different network protocols. (see bridge, router)

Frame Relay - A method used to bundle data and routing information into frames without overhead information such as error checking. Frames vary in length and utilize bandwidth of the network accordingly. The speed of frame relay typically range from DS0 (64 Kbps) to T1 (1.544 Mbps).

Hertz - A unit of measurement for frequency of radio signals, electrical signals, and sound waves.

ISDN - Integrated Services Digital Network - A digital service, offered by telephone companies, to integrate voice and data signals onto a single phone line. The Basic Rate Interface (BRI) being offered today consists of two 64 Kbps channels and one 32 Kbps channel. This requires special interface equipment.

Kbps/Mbps - Kilo Bits Per Second - Thousand bits per second

Mega Bits Per Second - Million bits per second

LAN - Local Area Network - Connecting several computers within a room or building to allow sharing of files, printers, and other network services such as E-Mail, instructional software, administrative software, etc.

MHz/GHz - MegaHertz - 1. One million hertz. 2. Also used to measure the number of clock cycles a processor can perform within one second.

GigiHertz - One billion hertz.

Microwave - A short wavelength radio signal, considered to be above the frequency of 2000 mHz or 2 gHz.

MPEG - Motion Pictures Experts Group - A standard for compressing video signals into a digital format. It is becoming widely used for direct satellite services and Cable TV as well as competing with DVI as the newest standard for computer video. It has also played a large role in the development of HDTV.

Multi-Mode Fiber Optics - A fiber optic cable with a larger core diameter as compared to single-mode (typically 62.5 microns). This larger diameter allows the light waves to bounce around more, causing the light level to decrease faster. Multi-mode fiber is typically used for transmission of data signals for over short distances (less than 19,000 feet).

Multiplex - The two most common forms of multiplexing are Time Division and Frequency Division. In time division, information or bits are assigned certain time intervals within a given length of time, becoming part of a larger composite signal. This is typical in T1 transmissions. In frequency division, signals are assigned to different frequencies across the bandwidth of a given medium, allowing simultaneous transmission of all signals. This is typical in a Cable TV system or other type of broadband systems.

Nanometer - Unit of measurement in fiber optic communications to indicate the wavelength rating of a fiber. Lightwaves are measured in nanometers as opposed to cycles as in the electromagnetic spectrum. One nanometer represents one billionth of one meter.

Operating System - Software used to manage and control a computer. The OS typically controls how application software addresses input and output devices such a keyboards, printers, and disk drives, as well as provide the basic environment for controlling and managing all of the hardware connected to your computer.

Packet Switching - Packet switching bundles data into packets with routing information attached to the packet. It then uses a shared telephone switching network to route data to it's destination. Several standards can be applied to Packet Switching, most notable is a standard called X.25. Packet switching is typically limited to 56 Kbps.

Protocol - A set of rules to define and control how data is transferred across a particular network.

Ring Topology - A network topology that connects all users in a daisy chain fashion with the last segment completing the ring at the beginning.

Router - A device used to route and manage several networks allowing only the necessary connections between two users or nodes. Instead of allowing a user request to wander across several networks looking for another certain user, the router has the intelligence to know which network to send a request to, reducing unnecessary data traffic on other networks.

Satellite Dish - A device capable of receiving and/or transmitting signals to and from satellites. Commonly used in the K-12 market for receiving distance learning video programs and/or sharing resources with neighboring or global school partners. A dish that is used to receive signals only is known as a "downlink." A dish that is use to send signals only is known as an "uplink."

Single Mode Fiber Optics - A fiber optic cable having a core diameter of less than 10 microns. The diameter of this medium and (its required equipment) provide a greater distance capability, in comparison with Multi-Mode fiber optics. (See Multi-Mode Fiber Optics)

SONET - Switched Optical Network - A fiber optic based switched network used for telephone and data communications. SONET has several speeds identified in it's hierarchy ranging from OC-1 at 51.84 Mbps up to OC-255 at 13.2192 Gbps.

Standards - Publications usually written by industry or government associations to establish guidelines for manufacturing, designing or developing a product. Standards are very useful for establishing compatibility among different manufacturers or vendors products.

Star Topology - A network topology that uses a central hub and connects users with individual point to point connections from the hub to each device or user.

T1/DS1 - A digital telephone circuit capable of being divided into 24 separate voice circuits. Equal to 1,544 Mbps (1,544,000 bits per second). DS1 is the framing format for T1 (1.544 Mbps) digital circuits.

T3/DS3 - A wide bandwidth digital telephone circuit capable of carrying 28 DS1 (T1) circuits. It operates at 44.756 Mbps. (44,756,000 bits per second) DS3 is the framing format for T3 (44.736 Mbps) digital circuits.

TCP/IP - Transmission Control Protocol/Internet Protocol - A wide area network architecture/protocol very suitable for interconnecting several smaller networks. The most common protocol used on Internet.

Token Ring - A baseband network protocol used to send and receive data by using "tokens". Based on token passing, a baseband networking protocol outlined in the IEEE 802.5, which expands the capabilities of token passing to provide dual paths, thus providing redundancy in the networking medium. Token Ring uses a request and send management method as opposed to a listen and random transmit method used by Ethernet.

Topology - The physical or logical structure of a network.

V-Sat - Very Small Aperture Terminal - A two way satellite communication network that utilizes small satellite dishes that are capable of transmitting as well as receiving. They are used in data networks, bypassing conventional telephone networking methods. These systems typically run up to 56 Kbps.

WAN - Wide Area Network - To connect computers or LAN's between buildings across a campus, community, or larger area