In Web pages, it refers to the ability of a Web page to be viewed by everyone,
especially people with disabilities who use various assistive technologies. Accessible
Web pages take into account the special needs of visitors with auditory, visual,
mobility, and cognitive impairments and give those users an equivalent browsing
experience to that of non-disabled visitors.

Academic accommodations vary depending upon the documented needs of the
individual student and are based on the demonstration that an accommodation is
reasonable and necessary to improve the direct impact of a substantial limitation on
a major life function.

Americans with Disabilities Act (ADA)
Enacted July 26, 1990, the ADA prohibits discrimination and ensures equal
opportunity for persons with disabilities in employment, state and local government
services, public accommodations, commercial facilities, and transportation. It also
mandates the establishment of TDD/telephone relay services. The Department of
Justice enforces the ADA’s requirements in three areas:
Title I Employment practices by units of state and local government
Title II Programs, services, and activities of state and local government
Title III Public accommodations and commercial facilities

Alternate Format
Translation of information into a variety of accessible formats including Braille, large
print, ASCII text, audio cassette, captioning, electronic text and more.
Alternative Keyboard Layout
Allows people who experience difficulty with conventional keyboard designs to use
computers. The products available range from key guards that prevent two keys
from being pressed simultaneously, to alternative keyboards with differing layouts,
sizes, etc. for people who have specific needs, to alternative input systems which
require other means/methods of getting information into a computer.

Alternative Mouse System
Alternative pointing devices are used to replace the mouse. Includes trackballs and
other pointing devices.

Alternative Text (ALT Text)

Descriptive text included in IMG tags that appears when the mouse is held over the
image. The text should provide a concise alternative description of the image or
image map that will make sense when heard through a screen reader. Include ALT
text in your code like this: <img src="robot-image.gif" alt="Old NetMechanic Robot

Assistive Technology
As defined by the Assistive Technology Act of 1998, the term refers to “any item,
piece of equipment, or product system, whether acquired commercially, modified, or
customized, that is used to increase, maintain, or improve the functional capabilities
of individuals with disabilities.” Assistive technologies include: screen readers and
magnifiers, closed captioning, alternative keyboards, and other special software and
equipment that makes information devices more accessible. Also referred to as
"Adaptive Technology."

Auditory Impairment
Conditions where people are completely deaf or hard of hearing. They require visual
representations (captions or transcripts) of information contained in audio files.

A signal that is received in the same form in which it is transmitted, while the
amplitude and frequency may vary.

The device that sends out and/or receives signals from the satellite. Also referred to
as a satellite dish.

The amount of variety in a signal. Commonly thought of as the height of a wave.
American Standard Code for Information Interexchange (ASCII) – a computer
language used to convert letters, numbers, and control codes into a digital code
understood by most computers.

Communication in which interaction between parties does not take place

Asynchronous Transmission Mode (ATM)
A method of sending data in irregular time intervals using a code such as ASCII.
ATM allows most modern computers to communicate with one another easily.

Audio Bridge
A device used in audio conferencing that connects multiple telephone lines. Audio
conferencing voice only connection of more than two sites using standard telephone

A primary communication path connecting multiple users.

The amount of spectrum a communication channel (analog or digital) uses,
measured in hertz (Hz).

A range of frequencies between defined upper and lower limits.

A computer language developed with only two letters in its alphabet.

The nickname for a satellite.

Abbreviation for a single binary digit.

Software package available for use online or through download that evaluates Web
pages for accessibility mainly to visually impaired users. Sites that pass are entitled
to display the “Bobby Approved” icon. However, that icon does not mean that those
sites also comply with all of Section 508’s accessibility requirements. Download
Bobby at the

A system of touch reading and writing for the blind, which employs embossed dots
evenly arranged in quadrangular letter spaces or cells.

Braille Display
Assistive technology that raises or lowers dot patterns based on input from an
electronic device such as a screen reader or text browser.

A single computer word, generally eight bits.

A term used to refer to high-speed communication networks that are designed to
handle bandwidth-intensive applications.

To transmit the same information to multiple receivers simultaneously over a satellite
system, radio/TV station, data communications network or e-mail system.

Software that allows you to find and see information on the Internet.

Refers to the frequency in the 3.4 GHz to 7GHZ range. Portions of this band are
dedicated to satellite communications. Satellite downlinks are 3.7 to 4.2 GHz.

A place to store something temporarily. Web pages you request are stored in your
browser’s cache directory on your hard disk. When you return to a page you’ve
recently viewed, the browser gets it from the cache rather than the original server,
saving you time and the network additional traffic. You can usually vary the size of
your cache, depending on your practical browser.

Cache Server
A server relatively close to Internet users and typically within a business enterprise
that saves (caches) Web pages and possibly FTP and other files that all users have
requested. The cache server rather than the Internet can satisfy successive
requests for these pages or files. A cache server not only gets information more
quickly but also reduces Internet traffic.

A text transcript of the audio portion of a video file that synchronizes the text to the
action contained in the video.

Captioning Types
See Distance Education: Access Guidelines for Students with Disabilities, Appendix
III (Off-line captioning, Realtime Captioning, Closed captions, Open captions, Closed
caption decoder, Roll-up and Pop-On captions, and Captioning Service Providers)

Cognitive Impairments
It includes individuals with general processing difficulties (developmental disabilities,
brain injury, etc.), people with very specific types of deficits (short term memory,
inability to remember proper names, etc.), learning disabilities, language delays, and

Central Processing Unit (CPU)
The component of a computer in which data processing takes place.
The smallest subdivision of a circuit, usually with a path in only one direction.

Coder/DeCoder (CODEC)
A device used to convert analog signals to digital signals for transmission and
reconverts signals upon reception at the remote site while allowing for the signal to
be compressed for less expensive transmission.

Communication Technology
A system for sending and receiving voice, video and data electronic information.

Reducing the amount of bandwidth needed to transmit video or audio by digitizing an
analog signal, thus increasing the ability able to load multiple services on a satellite

Compressed Video
When video signals are downsized to allow travel along a smaller carrier.
Computer-Assisted Instruction (CAI)
Teaching process in which a computer is utilized to enhance the learning
environment by assisting students in gaining mastery over a specific skill.

Course Session
Used in Management Information System reporting to indicate the separate records
on a section of a course that distinguishes when a part of the section is scheduled at a
different time, on different days, in a different facility, or with several instruction

Educational software and materials (such as programs) for a distance education

The nebulous “place” where humans interact over computer networks. Coined by
William Gibson in Neuromancer.

Direct Broadcast Satellite. A service that uses satellites to broadcast multiple
channels of television programming directly to small dish antennas.

A device used to unscramble encrypted or “scrambled” television signals.

Desktop Videoconferencing
Videoconferencing on a personal computer.

Dial-up Teleconference
Using public telephone lines for communications links among various locations.

A quantification scheme that allows the conversion of analog information into bits of
data. Digitization allows for signal compression and for maintaining signal integrity.

Digital Video Interactive(DVI)
A format for recording digital video onto compact disc allowing for compression and
full motion video.

Descriptive Narration
Aids blind and visually impaired viewers with descriptive narration of key visual
elements of video programming, including descriptive information on scenery, action,
expressions/movements and costumes/props – everything that will give the viewer a
better “picture” of what is happening.

Distance Education
Instruction in which the instructor and student are separated by distance and interact
through the assistance of communication technology.

Distance Education Course
The delivery of instruction and separation of the student and instructor that utilizes
one or a combination of technologies 51 percent or more of the time is considered a
Distance Education course/section/session.

Distance Learning
The desired outcome of distance education.

The transmission of radio frequency signals from a satellite to an earth station.

Using the network to transfer files from one computer to another.

Earth Station
A ground-based antenna and associated equipment used to receive and/or transmit
telecommunications signals via satellite.

Echo Cancellation
The process of eliminating the acoustic echo in a videoconferencing room.

Electronic Mail (E-mail)
Sending messages from one computer user to another.

Facsimile (FAX)
System used to transmit textual or graphical images over standard telephone lines.

Federal Communications Commission. The U.S. federal regulatory agency
responsible for the regulation of interstate and international communications by
radio, television, wire, satellite, and cable.

Device mounted at the focal point of the antenna that gathers signals reflected from
the dish. Also a television signal source.

Fiber Optic Cable
Glass fiber that is used for laser transmission of video, audio, and/or data.

Fifty-one (51%) Rule
A course/section or session is defined as DE if technology is used 51 percent or
more of the time required to deliver instruction during the course term and where the
student and instructor are separated by distance.

File Transfer Protocol (FTP)
A protocol that allows you to move files from a distant computer to a local computer
using a network like the Internet.

The coverage area of the earth’s surface within which the signals of a specific
satellite can be received.

The rate at which a signal (e.g. electrical current) alternates. The standard unit of
frequency is the hertz, abbreviated Hz. If a signal completes one cycle per second,
then the frequency is 1 Hz; 60 cycles per second equals 60 Hz.
Hz Hertz. The name of the basic measure of frequency with which an
electromagnetic wave completes a full cycle from its positive to its
negative pole and back again. Each unit is equal to one cycle per second.
KHz Kilohertz. Refers to a unit of frequency equal to 1,000 Hertz.
MHz Megahertz. Refers to a frequency equal to one million Hertz.
GHz Gigahertz. Refers to a frequency equal to one billion Hertz.

Frequently Asked Questions (FAQ)
A collection of information on the basics of any given subject, often used on the

Fully Interactive
A variety of distance education in which the technology employed provides an
immediate opportunity for exchange between participants.

Full Motion Video
Signal which allows transmission of complete action taking place at the origination

Fully Interactive Video
(Two-way interactive video) Two sites interact with audio and video as if they were

Geosynchronous Orbit
An orbit 22,300 miles above the Earth’s equator where satellites circle at the same
rate as the earth’s rotation.

Greenwich Mean Time. The time zone that includes Greenwich, England is bisected
by zero degrees longitude. This is the time notation that is used for booking
international satellite time.

Location where cable television systems collect and distribute satellite programming.

Home Page
A document with an address (URL) on the world wide web maintained by a person
or organization which contains pointers to other pieces of information.

A network computer that can receive information from other computers.

Hybrid Course
A course utilizing more than one mode of instructional delivery. Instruction may be
delivered by such modes as, for example, the internet, email, video, and the

Hybrid Satellite
A satellite that carries two or more different communications payloads (i.e. C-band
and Ku-band).

Hypertext Mark-up Language (HTML)
The code used to create a home page and is used to access documents over the

Hypertext Transfer Protocol (HTTP)
The protocol used to signify an Internet site is a WWW site, i.e. HTTP is a WWW

A document which has been marked up to allow a user to select words or pictures
within the document, click on them, and connect to further information.

Inclined Orbit
A condition that occurs when a satellite is no longer station-kept in the north-south
plain. A satellite operator might do so to extend the life of a satellite because fuel will
only be used to perform station-keeping in the east-west plain. The inclination
happens gradually over time, and once it becomes excessive, the satellite is deorbited.

Independent Study
A broad category of courses for which state reimbursement is based upon number of
units of credit rather than amount of student attendance. For apportionment
purposes, distance education is one variety of independent study.

A back-and-forth dialog, using communication technology, between the user and the

Instructional Television Fixed Service (ITFS)
Microwave-based, high-frequency television used in educational program delivery.

Interactive Media
Frequency assignment that allows for a two-way interaction or exchange of

Integrated services digital network. A standard for the integrated transmission of
voice, video, and data developed by the Consultative Committee on International
Telephony and Telegraphy (CCITT).

Joint pictures expert group. A subgroup of ISO, which has established international
standards for the digital compression of still pictures.

Primarily used in satellites operating at 30Ghz uplink and 20 GHz downlink and is
intended in support of future applications such as mobile voice. A portion of the RF
spectrum located between 18 GHz and 31 GHz.

Refers to the frequency in the 12 GHz to 14 GHz range used in support of such
applications as broadcast TV, DBS, and direct-to-home television.

Large Print
Large print text is oversized print intended for use by the visually impaired.

Low noise blockdownconverter. An electronic part of a satellite earth station that is
used to amplify the signal collected by the reflector and the feedhorn.

An e-mail program that allows multiple computer users to connect onto a single
system, creating an on-line discussion.

Local Area Network (LAN)
Two or more local computers that are physically connected.

Media Access Generator. Tool that allows Web authors to add captions to three
multimedia formats: Apple’s QuickTime, the World Wide Web Consortium’s
Synchronized Multi-media Integration Language (SMIL) and Microsoft’s
Synchronized Accessible Media Interchange (SAMI) format. MAGpie can also
integrate audio descriptions into SMIL presentations.

Multi-channel per carrier. A signal comprised of multiple digital streams that are
multiplexed into a single stream, which is then transmitted on single carrier. This is
typically used to combine multiple CDV signal into one.

Electromagnetic waves that travel in a straight line and are used to and from
satellites and for short distances (i.e., up to 30 miles).

Mobility Impairments
Physical impairments limit movement and fine motor controls like walking, lifting, or
using a mouse or keyboard. People with physical impairments often require adaptive
or assistive technologies to use computers or navigate through Web sites

A piece of equipment to allow computers to interact with each other via telephone
lines by converting digital signals to analog for transmission along analog lines.

An example of browser software that allows WWW use.

MPEG the Moving Picture Experts Group, develops standards for digital video and
digital audio compression. It operates under the auspices of the International Organization for Standardization. The MPEG standards are evolving, each designed
for a different purpose.

Any document which uses multiple forms of communication, such as text, audio,
and/or video.

Multi-Point Control Unit (MCU)
Computerized switching system which allows point-to-multipoint videoconferencing.

National Association of Broadcasters. A U.S.-based organization that fosters and
promotes radio and television broadcasting. PanAmSat has a booth at the NAB
trade show held once a year in Las Vegas.

An example of browser software that allows you to design a home page and to
browse links on the WWW.

A series of points connected by communication channels in different locations.

Non-text Equivalent
Content provided through audio files, sign language, or other visual means to
convey information to people with visual or cognitive disabilities.

Active and prepared for operation. Also suggests access to a computer network.

Origination Site
The location from which a teleconference originates.

Supports the primary mission of the satellite, the receipt and transmission of signals,
and comprises systems that include receivers, multiplexers, high-powered amplifiers
and signal processing.

Point of Presence (POP)
Point of connection between an inter-exchange carrier and a local carrier to pass
communications into the network.

Transmission between two locations.

Transmission between multiple locations using a bridge.

The orientation of a transmitted/received signal. Signals can have circular or linear

A software package which allows a user to have a direct connection to the Internet
over a telephone line.

A formal set of standards, rules, or formats for exchanging data that assures
uniformity between computers and applications.

Real Time
An electronic operation that is performed in the same time frame as its real-world
counterpart. For example, real time video transmission.

Real Time Transcription
Transcribers attend class and write the spoken word on a steno machine. This
process instantly creates English text so that one or more hearing impaired students
may not only see what is being said, but non-oral students can utilize the keyboard
to ask questions.

Satellite TV
Video and audio signals are relayed via a communication device that orbits around
the earth.

Single Channel Per Carrier. A scheme in which only one signal is loaded on a

Screen Magnifier
Software program that magnifies all or part of a computer screen to make the
content visible to users with visual impairments.

Screen Reader
Software that reads the content of a computer screen aloud. Screen readers can
only interpret text content, so all graphic and multimedia must have alternative text
descriptions using ALT text, captions, transcripts, or other methods.

Serial Line Internet Protocol (SLIP)
Allows a user to connect to the Internet directly over a high speed modem.

A computer with a special service function on a network, generally receiving and
connecting incoming information traffic.

Simplex Operation
Transmissions sent in only one direction of a telecommunications channel.

Slow Scan Converter
Transmitter/receiver of still video over narrow band channels. In real time, camera
subjects must remain still for highest resolution.

Space Segment
A term that describes the portion of the total communications satellite system that is
physically located in orbit around the earth.

The range of electromagnetic radio frequencies used in transmission of voice, data
and television.

Streaming video is a sequence of “moving images” that are sent in compressed form
over the Internet and displayed by the viewer as they arrive. Streaming media is
streaming video with sound. With streaming video or streaming media, a Web user
does not have to wait to download a large file before seeing the video or hearing the
sound. Instead, the media is sent in a continuous stream and is played as it arrives.
The user needs a player, a special program that uncompresses and sends video
data to the display and audio data to speakers. A player can be either an integral
part of a browser or downloaded from the software maker’s Web site.

Communication in which interaction between participants is simultaneous.

Sun Outage
When the sun passes behind a satellite in relation to the earth, and the sun’s energy
momentarily interferes with the satellite signals. Occurs two times each year during
spring and fall equinox.

Refers to bit rate of 1.544 million b/s for the United States. The European E-1
transmission bit rate is 2.048 Mb/s.

T-3 (DS-3)
A digital channel which communicates at a significantly faster rate than T-1.

The science of information transport using wire, radio, optical, or electromagnetic
channels to transmit receive signals for voice or data communications using
electrical means.

Two-way electronic communication between two or more groups in separate
locations via audio, video, and/or computer systems.

A video-based course which uses a fully integrated package of video instruction
combined with instructional support materials (for example, a textbook, a student
study guide, and a faculty resource guide). Telecourses are delivered in a variety of
ways, including television broadcast.

Telephone Relay Service
Telephone Relay Services (TRS) link people using a standard (voice) telephone with
people using a device called either a Text Telephone (TTY) or Telecommunications
Device for the Deaf (TDD). This device generally consists of a keyboard and display
screen. Calls are routed through a communications operator who has both sets of
equipment and who acts as the intermediary between callers

Technical ground facility used for satellite communications. PanAmSat operates six
domestic teleports: Atlanta, GA; Napa, CA; Fillmore, CA; Long Beach, CA; Castle
Rock, CO; Homestead, FL; and Spring Creek, NY.

A course which merges a telecourse (see above) with the internet, providing the
addition of online content, instructional/learning activities, resource links, and
instructor and student interaction.

Text Equivalent
Text content that describes information on the screen that’s contained in graphic,
Flash, or other multimedia files. Text equivalent is often provided using captions,
ALT text, or transcripts. The alternate text must convey the same function or
purpose for the user with a disability as the non-text content does for others.

Text Speech Software
Text-to-Speech software is used to convert words from a computer document (e.g.
word processor document, web page) into audible speech spoken through the
computer speaker. This differs from screen reader technology because it doesn’t
read any system information or alternative text descriptions.

Text Transcript
A text description of information contained in audio files.

Most deaf people use a device called a TTY (also known as a TDD), which is a
simple keyboard that connects to a telephone, often through an acoustic coupler.
When two people communicate via TTY, each sees what the other is typing.

An earth station feature that allows for tracking inclined satellites.

Transmission Control Protocol (TCP)
A protocol which makes sure that packets of data are shipped and received in the
intended order.

A radio frequency path through a satellite with a specific bandwidth, uplink/downlink
frequency and beam. Transponders can be sold in whole or can be segmented into
smaller pieces of bandwidth.

Video Teleconferencing
A teleconference including two-way video.

Virtual Equivalent
A mediated technology course that is regularly or irregularly scheduled and meets
the criteria for section 58003.1(a)(b)(c) can be considered comparable to a
classroom-based course.

Visual Impairment
Refers to conditions where people are blind, color blind, or have reduced vision
capabilities. Often, these people will use assistive technologies like screen readers
or magnifiers to help them use computers and navigate through Web sites.

Voice Recognition
Voice or speech recognition is the ability of a machine or program to receive and
interpret dictation, or to understand and carry out spoken commands

Uniform Resource Locator (URL)
The address of a homepage on the WWW.

Universal Design
Universal design is the design of products and environments to be usable by all
people, to the greatest extent possible, without the need for adaptation or
specialized design.

Refers to design features that make a product user friendly for the broadest number
of users. For instance, Web sites with usability problems could be hard to navigate,
difficult for disabled people to use, or have unclear instructions for use.


The transmission of radio frequency signals to a satellite from an earth station.

Web Accessibility Initiative, affiliated with the World Wide Web Consortium.
Coordinates with organizations around the world to increase the accessibility of the
Web through five primary areas of work: technology, guidelines, tools, education
and outreach, and research and development. The developer of web content
accessibility guidelines.

World Wide Web (WWW)
A graphical hypertext-based Internet tool that provides access to homepages
created by individuals, businesses, and other organizations.

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