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Section 508 Reference Guide Appendix D: Glossary

Acronyms and Abbreviations


Americans with Disabilities Act

Americans with Disabilities Act Accessibility Guidelines

Automated Information System

American National Standards Institute

See Application Programming Interface

American Standard Code for Information Interchange

American Sign Language

See Assistive Technology

Alliance for Telecommunications Industry Solutions

Center for Applied Special Technology

Computer-based training

Compact disc

Commercial off-the-shelf

Cathode ray tube

See Decibel

Dual Tone Multi Frequency

Digital television

Digital versatile disc

Examiner's Automated Search Tool

Electronic Industries Association

See Electronic and Information Technology

European Telecommunications Standards Institute

Federal Communications Commission

GNU Network Object Model Environment

General Services Administration

The Hearing Aid Compatibility Act of 1988

See Hearing Carry Over

High-definition television

The Human Factors and Ergonomics Society

HyperText Markup Language

See Hertz

International Business Machines

International Electrotechnical Commission

Institute of Electrical and Electronic Engineers

IMS Global Learning Consortium

Internet Protocol

Integrated Services Digital Network

International Organization for Standardization

Information technology

Information Technology Technical Assistance and Training Center

Interactive Voice Response

Job Access With Speech

Japan Electronic Industries Development Association

Liquid crystal display

Light-emitting diode

Media Access Group

Media Access Generator

Multiple Document Interface

Microsoft Active Accessibility

National Center on Accessing the General Curriculum

National Center for Accessible Media

National Center for the Dissemination of Disability Research

National Institute for Standards and Technology

National Television System Committee, or the eponymous standard for analog TV signal transmission in North America and other parts of the world.

Original Equipment Manufacturer

Occupational Safety and Health Administration

See Phase Alternating Line

Private Branch Exchange

Personal computer

Peripheral Component Interconnect

Personal Computer Memory Card International Association

Personal digital assistant

Portable Document Format

IBM Personal System/2, or the keyboard and mouse interfaces that were introduced with this personal computer.

Public Switched Telephone Network

Radio frequency

Red green blue

See Secondary Audio Program

Small Computer System Interface

Synchronized Multimedia Integration Language

Scalable Vector Graphics

Telephone Application Programming Interface

Telecommunications device for the deaf. See Teletypewriter.

Telecommunications Industry Association

Tagged Image File (Format)

See Teletypewriter


Uniform Resource Locator

Universal Serial Bus

United States Patent and Trademark Office

See Voice Carry Over

Video cassette recorder

Video Home System

Voice over Internet Protocol

World Wide Web Consortium

Web Accessibility Initiative

Web Content Accessibility Guidelines

Web Accessibility in Mind

Extensible Markup Language


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Accessibility feature
A product function that is designed to assist disabled users (e.g., a visual alert for audio feedback to assist hard of hearing or deaf users, or "sticky keys" which allow dexterity impaired users to press key combinations sequentially, as opposed to simultaneously).

Acoustic coupling
For a telecommunications product, a coupling that is accomplished by means of sound. Acoustic coupling is often ineffective because it is susceptible to:
  • ambient noise
  • acoustic feedback
  • incompatibility between the hearing technology and the earpiece of the telecommunications product

(Contrast with inductive coupling.)


Active region
In an image map on a webpage, a set of coordinates or a geometric shape that is associated with a link.

Ambient noise
The background sound of an environment in relation to which all foreground sounds are heard.

Automated visual movement created by and under the control of a software application that is displayed on a user interface. Note that this definition does not include video, which is the result of differences in the images between individual video frames, and is not created by the software application.

Application Programming Interface (API)
A standard way for programs to communicate with each other, including the operating system, and with input and output devices. For example, an API may affect how programs display information on a monitor or receive keyboard input via the operating system.

Assistive Technology (AT)
Any item, piece of equipment, or system, whether acquired commercially, modified, or customized, that is commonly used to increase, maintain, or improve functional capabilities of individuals with disabilities. The USPTO maintains a baseline of AT products that will effectively support individuals with disabilities and will function with proprietary systems.

Audio descriptions
Spoken equivalents of visual information in a video or multimedia presentation. E.g., verbal explanations of movement, scenery, facial expressions, or diagrams.

Back office
An exemption for products that are not human-interactive. This normally includes products in a data center or telecommunications closet. However, if a product is in the data center, but can be controlled via remote access, then the product must be Section 508 compliant. Or, if the same product were installed in an office, it would have to be compliant. 1194.3(f) states, "Products located in spaces frequented only by service personnel for maintenance, repair, or occasional monitoring of equipment are not required to comply with this part."

A character set predating EBCDIC and ASCII and used originally and primarily on teleprinters. (Named for inventor Émile Baudotmile Baudot.) Also known as Baudot code.

Biometric controls
Controls that are activated by a particular biological feature or physical characteristic.

Bitmap image
A graphic image. A bitmap image may be purely decorative, or may indicate the presence of a programmatic element. The word "bitmap" in this context does not imply any particular graphics file format.

1. (noun) an emission of light that varies according to a cycle, i.e., at regular or irregular time intervals.
2. (verb) to display such an emission of light.
Also known as flash or flicker.

In a text edit field, an on-screen indication of the text input focus.

Client-side image map
An image map for which the link information is included in the webpage. When a user clicks on a client-side image map with a mouse, the web browser uses the pixel coordinates of the click to determine which region of the image map to activate. If that region is an active region, then the browser activates the associated link. Similarly, a keyboard user can browse the active regions of a client-side image map, and can activate them like image links.

Closed captions
Optional alternative text in a video or multimedia presentation. Closed captions can be activated, deactivated, and modified by the user.

Concerning the cochlea, a tube within the inner ear that contains nerve endings essential for hearing.

Commercially Non-Available
An exemption that applies if, at the time of procurement of a product, there is nothing on the market in that product category that conforms to the full set of Section 508 standards. In this case, the most compliant product must be procured.

Complex data table
A data table that organizes data using more than a simple row/column structure. E.g., categories of data may have subcategories, or data may belong to more than two categories. Complex data tables can represent n-dimensional data. (Contrast with simple data table.)

For a telecommunications product, a connection between the product and a hearing technology (e.g., between a telephone and a hearing aid).

Data table
A table that contains information that is organized into categories.

Decibel (dB)
Unit of relative sound intensity.

Display attributes
Settings that affect the visual presentation of the user interface of a software application or operating system (e.g., font, font size, and color).

Electronic and Information Technology (EIT)
1. Includes information technology and any equipment or interconnected system or subsystem of equipment, that is used in the creation, conversion, or duplication of data or information. The term electronic and information technology includes, but is not limited to, telecommunications products (such as telephones), information kiosks and transaction machines, World Wide Web sites, multimedia, and office equipment such as copiers and fax machines. The term does not include any equipment that contains embedded information technology that is used as an integral part of the product, but the principal function of which is not the acquisition, storage, manipulation, management, movement, control, display, switching, interchange, transmission, or reception of data or information. For example, HVAC (heating, ventilation, and air conditioning) equipment such as thermostats or temperature control devices, and medical equipment where information technology is integral to its operation, are not information technology. [The Access Board]

2. Human-interface and human-interactive technology products of the following types:
  • software programs that function within the circuitry of hardware devices, and that interface with human users through input/output devices that are connected to the hardware devices locally or through a network
  • hardware devices that operate by means of analog or digital electronic circuitry, usually including firmware or software programs that function within the circuitry
  • data that is stored, transmitted or presented in an analog or digital format


A condition under which a product or part of a product is allowed to be noncompliant with one or more technical standards of Section 508. These conditions include back office installation, avoidance of fundamental alteration, and commercial non-availability. The USPTO does not have any areas that would qualify for the exemption of national security.

See Blink

See Blink

In a graphical user interface, a window (e.g., a button) or a location within a window (e.g., position of a text cursor or mouse pointer), to which the operating system will direct user input. Users can set the focus by using the keyboard, the mouse or other input devices.
Also known as input focus.

Fundamental alteration
An exemption that applies if an essential design change would be required in order to make a product Section 508 compliant. 1194.3(e) states, "This part shall not be construed to require a fundamental alteration in the nature of a product or its components."

The ratio of output to input in electrical signals (e.g., amplification).

Hearing Carry Over (HCO)
Strategy of using a TTY for outbound text only. HCO allows a person with a speech disability to hear a response from their party directly, and use the TTY for sending text in the outbound direction.

Hertz (Hz)
A unit of frequency equal to one cycle per second.

Image map
On a webpage, an image that links to multiple webpages or resources. The image is subdivided into regions, each of which may link to a different resource. See Active region.

Incremental volume control
Volume control that allows more than one step between minimum and maximum levels. The size of the increment may be small enough to effectively provide a continuous, or variable, volume control.

Inductive coupling
For a telecommunications product, a coupling that is accomplished through variance of a shared magnetic field. Also known as magnetic wireless coupling. (Contrast with acoustic coupling.)

Input focus
See Focus

Magnetic wireless coupling
See Inductive coupling

Multimedia presentation
An exhibition that includes more than one means of conveying information (e.g., text, graphics, video, sound).

Non-destructive timeout
A process timeout in which user input is retained, allowing the user to resume the process with minimal difficulty.

Open captions
Permanent alternative text in a video or multimedia presentation. The user cannot activate or deactivate open captions, because they are integrated into the video or presentation.

Operable control
A component of a hardware product that requires physical contact for normal operation (e.g., mechanically operated controls, keyboards, or keypads).

Phase Alternating Line (PAL)
A standard for analog TV signal transmission in Europe and many other parts of the world.

Plain text
A sequence of letters, numbers and/or other printable characters.

Program element
See User interface element

Programmatic element
See User interface element

Programmatically exposed
Available from a software application to the operating system or other software applications via an API.

Secondary Audio Program (SAP)
An auxiliary sound channel that can be transmitted in addition to a television station's main audio channel.

Section 504
Legal provision for individual accommodation of persons with disabilities.

Section 508
Legal provision for the IT infrastructure that enables faster and more effective solutions for persons with disabilities.

Server-side image map
An image map for which the link information resides on the server. When a user clicks on a server-side image map with a mouse, the web browser appends the pixel coordinates (x,y) of the click to a given server link. (When a keyboard user activates this image map, the web browser uses (0,0).) Then the browser activates the link. The server interprets the coordinates and performs some action.

Simple data table
A data table that represents each category of data with one row or column of cells. The meaning of each cell is based on its contents and its row and/or column position. Simple data tables can represent 2-dimensional data. (Contrast with complex data table.)

A two-dimensional group of rectangular cells organized into rows and columns.

Table header
The name of a category of data in a data table row or column. In a simple data table, column headers are provided in the first row and apply to the data cells in their respective columns; similarly, row headers are provided in the first column and apply to the data cells in their respective rows. In a complex data table, a column header may be defined in any row, and may apply to multiple columns or to a few cells in a column; similarly, a row header may be defined in any column, and may apply to multiple rows or to a few cells in a row.

Tactilely discernible
Able to be detected, and distinguished from adjacent objects, by means of touch.

An alternate or supplemental input device for a hearing aid, consisting of a tiny coil of wire around a core that will induce an electric current in the coil when in the presence of a changing magnetic field.

Teletypewriter (TTY)
Communications device used by people who are deaf, hard of hearing, or speech impaired to communicate over networks designed to carry voice.

Textual information
Any information presented using words or characters. Images of text are included in this definition.

1. (noun) a product or function reset that occurs when a user provides no action or input within a certain time interval.
2. (intransitive verb) to reset as described.

User interface element
Any component of a software or web application user interface intended to allow the user to access information or perform an action (e.g., a menu, tab, radio button, text field, etc.).
Also known as program element or programmatic element.

Voice Carry Over (VCO)
Strategy of using a TTY for inbound text only. VCO allows people who are hard of hearing or oral deaf (deaf with intelligible speech) to use a TTY without typing. They only use the TTY for reading during the inbound direction of the call, and talk to the other party by speaking into a microphone.


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Last Modified: 5/23/2012 9:32:47 AM