1. C101 General
  2. C102 Referenced Standards
  3. C103 Definitions

C101 General

C101.1 Purpose.  This document contains scoping and technical requirements for telecommunications equipment and customer premises equipment that are accessible to and usable by individuals with disabilities.  Compliance with these standards is mandatory for telecommunications manufacturers pursuant to the Telecommunications Act of 1996 (47 U.S.C. 255).

C101.2 Equivalent Facilitation.  The use of an alternative design or technology that results in substantially equivalent or greater access to and use of data and information by individuals with disabilities than would be provided by conformance to a requirement in Chapters 4 through 6 of this document is permitted.  The functional performance criteria in Chapter 3 shall be used to determine whether substantially equivalent or greater access to and use of data and information is provided to individuals with disabilities.

C101.3 Conventional Industry Tolerances.  Dimensions are subject to conventional industry tolerances except where dimensions are stated as a range.

C101.4 Units of Measurement.  Measurements are stated in metric and U.S. customary units.  The values stated in each system (metric and U.S. customary units) may not be exact equivalents, and each system shall be used independently of the other.

C102 Referenced Standards

C102.1 Incorporation by Reference.  The specific editions of the standards and guidelines listed in C102 are incorporated by reference in this document and are part of the requirements to the prescribed extent of each such reference.  The Director of the Federal Register has approved the standards for incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.  Copies of the referenced standards may be inspected at the Access Board, 1331 F Street NW, Suite 1000, Washington, DC  20004; or at the National Archives and Records Administration (NARA).  For information on the availability of the referenced standards at NARA, call (202) 741-6030, or go to:

C102.2 ATSC.  Copies of the referenced standard may be obtained from the Advanced Television Systems Committee, 1776 K Street NW, Suite 200, Washington, DC  20006-2304 (

A/53 Digital Television Standard, Part 5: 2010 AC-3 Audio System Characteristics (see 410.1.1).

C102.3 ANSI/IEEE.  Copies of the referenced standard may be obtained from the Institute of Electrical and Electronics Engineers, 10662 Los Vaqueros Circle, P.O. Box 3014, Los Alamitos, CA 90720-1264 (

ANSI/IEEE C63.19-2011 American National Standard for Methods of Measurement of Compatibility between Wireless Communications Devices and Hearing Aids (see 408.4.1).

Advisory C102.3 ANSI/IEEE.  ANSI/IEEE C63.19-2011 provides a uniform method of measurement for compatibility between hearing aids and wireless communications devices.

C102.4 ITU-T.  Copies of the referenced standards may be obtained from the International Telecommunication Union, Telecommunications Standardization Sector, Place des Nations CH-1211, Geneva 20, Switzerland (

ITU-T Recommendation G.722 (November, 1988):  General Aspects of Digital Transmission Systems, Terminal Components, 7 kHz Audio-Coding within 64 kbits/s, (see 408.5).

Advisory C102.4 ITU-T.  G.722 is an ITU-T standard coder-decoder program that provides 7 kHz wideband audio at data rates from 48, 56, and 64 kbits/s.  This standard provides a significant improvement in speech quality over earlier standards.

C102.5 IETF.  Copies of the referenced standard may be obtained from the Internet Engineering Task Force (

RFC 4103 RTP Payload for Text Conversation (2005), (see 408.6.3.2).

Advisory C102.5 IETF.  This standard describes how to carry real time text conversation session contents in RTP packets.  Real time text conversation is used alone or in connection with other conversational modalities to form multimedia conversation services.  Examples of other conversational modalities are video and voice.  Real time text in multimedia conversation sessions is sent character-by-character as soon as it is available, or with a small delay for buffering.

C102.6 TIA.  Copies of the referenced standards, published by the Telecommunications Industry Association, may be obtained from IHS, 15 Inverness Way East, Englewood, CO  80112 (

TIA 825-A (2003) A Frequency Shift Keyed Modem for Use on the Public Switched Telephone Network (see 408.6.3.1).

TIA 1083 (2007) Telephone Terminal Equipment Handset Magnetic Measurement Procedures and Performance Requirements (see 408.4.2).

Advisory C102.6 TIA.  TIA 825-A is the standard for TTY signals on the publicly switched telephone network interface.  TIA 1083 defines measurement procedures and performance requirements for the handset generated audio band magnetic noise of wire line telephones, including digital cordless telephones.

C102.7 W3C.  Copies of the referenced guidelines may be obtained from the W3C Web Accessibility Initiative, Massachusetts Institute of Technology, 32 Vassar Street, Room 32-G515, Cambridge, MA  02139 (

Web Content Accessibility Guidelines (WCAG) 2.0, W3C Recommendation, 11 December 2008 (see C203.1, C205.2, 405.1 Exception, 501.1 Exception, 504.2, 504.3, 504.4, 602.3.1).

Advisory C102.7 W3C.  The Web Content Accessibility Guidelines (WCAG) offer a series of recommendations to make web content more accessible to all users, including persons with disabilities.

C103 Definitions

C103.1 Terms Defined in Referenced Standards.  Terms defined in referenced standards and not defined in C103.4 shall have the meaning as defined in the referenced standards.

C103.2 Undefined Terms.  The meaning of terms not defined in C103.4 or in referenced standards shall be as defined by collegiate dictionaries in the sense that the context implies.

C103.3 Interchangeability.  Words, terms, and phrases used in the singular include the plural and those used in the plural include the singular.

C103.4 Defined Terms.  For the purpose of this document, the terms defined in C103.4 have the indicated meaning.

Alternate Formats.  Formats usable by individuals who are blind or have low vision.

Assistive Technology (AT).  Any item, piece of equipment, or product system, whether acquired commercially, modified, or customized, that is used to increase, maintain, or improve functional capabilities of individuals with disabilities.

Authoring Tool.  Any application that can be used by authors (alone or collaboratively) to create or modify content for use by other authors or end users.

Closed Functionality.  Characteristics that prevent a user from attaching or installing assistive technology.  Examples of ICT with closed functionality are self-service machines, information kiosks, set-top boxes, and devices like printers, copiers, fax machines, and calculators.

Content.  Information or sensory experience communicated to the user by ICT.  Content includes the encoding that defines its structure, presentation, and interactions.

Customer Premises Equipment (CPE).  Equipment used on the premises of a person (other than a carrier) to originate, route, or terminate telecommunications or interconnected VoIP service.  Examples of CPE are telephones, routers, switches, residential gateways, set-top boxes, fixed mobile convergence products, home networking adaptors and internet access gateways which enable consumers to access communications service providers’ services and distribute them around their house via a Local Access Network (LAN).

Information and Communication Technology (ICT).  Any information technology, equipment, or interconnected system or subsystem of equipment for which the principal function is the creation, conversion, duplication, automatic acquisition, storage, analysis, evaluation, manipulation, management, movement, control, display, switching, interchange, transmission, reception, or broadcast of data or information.  Examples of ICT are electronic content, telecommunications products, computers and ancillary equipment, software, information kiosks and transaction machines, videos, IT services, and multifunction office machines which copy, scan, and fax documents.

Keyboard.  A set of systematically arranged alphanumeric keys or a control that generates alphanumeric input by which a machine or device is operated.  A keyboard includes tactilely discernible keys used in conjunction with the alphanumeric keys if their function maps to keys on the keyboard interfaces.

Label.  Text or a component with a text alternative that is presented to a user to identify content.  A label is presented to all users, whereas a name may be hidden and only exposed by assistive technology.  In many cases, the name and the label are the same.

Menu.  A set of selectable options.

Name.  Text by which software can identify a component to the user.  A name may be hidden and only exposed by assistive technology, whereas a label is presented to all users.  In many cases, the label and the name are the same.  Name is unrelated to the name attribute in HTML.

Operable Part.  A component of ICT used to activate, deactivate, or adjust the ICT.

Platform Accessibility Services.  Services provided by a platform enabling interoperability with assistive technology.  Examples are Application Programming Interfaces (API) and the Document Object Model (DOM).

Platform Software.  A collection of software components, that runs on an underlying software or hardware layer providing a set of software services to applications, that allows those applications to be isolated from the underlying software or hardware layer.

Programmatically Determinable.  Ability to be determined by software from author-supplied data that is provided in a way that different user agents, including assistive technologies, can extract and present the information to users in different modalities.

Readily Achievable.  Easily accomplishable and able to be carried out without much difficulty or expense.

Real Time Text.  Communications using the transmission of text by which characters are transmitted by a terminal as they are typed.  Real time text is used for conversational purposes.  Real time text also may be used in voicemail, interactive voice response systems, and other similar applications.

Specialized Customer Premises Equipment.  Assistive technology used by individuals with disabilities to originate, route, or terminate telecommunications or interconnected VoIP service.  Examples are TTYs and amplified telephones.

Telecommunications.  The signal transmission between or among points specified by the user of information and of the user’s choosing without change in the form or content of the information as sent and received.

Telecommunications Equipment.  Equipment, other than customer premises equipment, used by a carrier to provide telecommunications services, including software and upgrades integral to such equipment.

Telecommunications Manufacturer.  A fabricator or final assembler of telecommunications equipment, VoIP or customer premises equipment that sells to the public or to vendors.

Terminal.  Device or software with which the end user directly interacts and that provides the user interface.  For some systems, the software that provides the user interface may reside on more than one device.  Examples of such devices are a telephone and a server.

Text.  A sequence of characters that can be programmatically determined and that expresses something in human language.

TTY.  Equipment that enables interactive text based communications through the transmission of frequency-shift-keying audio tones across the public switched telephone network.  TTY includes devices for real time text communications and voice and text intermixed communications.  Examples of intermixed communications are voice carry over and hearing carry over.  One example of a TTY is a computer with TTY emulating software and modem.

Video Description.  A means to inform individuals who are blind or who have low vision about visual content essential for comprehension.  Video description provides audible descriptions of on-screen visuals.  Video description supplements the regular audio track of a program.  Video description is usually inserted between dialogue to provide information about actions, characters, and on-screen text.

Voice over Internet Protocol (VoIP).  A technology which provides real time voice communications.  VoIP requires a broadband connection from the user’s location and customer premises equipment compatible with Internet protocol.