Foreword

(This foreword is not part of American National Standard T1.523-2001)

This document is entitled Telecom Glossary 2000.

Footnotes are not part of this standard.

Future control of this document will reside with Accredited Standards Committee on Telecommunications, T1. This control of additions to the specification, such as protocol evolution, new applications, and operational requirements, will permit compatibility among U.S. networks. Such additions will be incorporated in an orderly manner with due consideration to the ITU-T layered model principles, conventions, and functional boundaries.

Suggestions for improvement of this standard will be welcome. These should be sent via e-mail to: evie@its.bldrdoc.gov and/or at bing@its.bldrdoc.gov

Contents

Foreword

The communication of facts and ideas depends upon a mutual understanding of terminology. This is particularly true in the rapidly growing field of information technology, in which there is a continuing need for a comprehensive source of agreed-upon technical terms and definitions.

Under an approved T1 standards project T1A1-20, a previously developed 5800-entry, search-engine equipped, hypertext telecommunications glossary, Federal Standard 1037C, Glossary of Telecommunication Terms, was updated and matured into this glossary, Telecom Glossary 2000. Following Letter Ballot #938 (which closed December 15, 2000), this updated glossary was posted on the Web as a American National Standard (ANS) at the Web address

http://www.its.bldrdoc.gov/projects/telecomglossary2000

The predecessor document, FED-STD-1037C, was approved by the Federal Telecommunication Standards Committee (FTSC) and published by the General Services Administration in 1996. The new Telecom Glossary 2000 enhances FED-STD-1037C by adding new terminology and by eliminating government-specific material and obsolete terms ( e.g., "Mosaic"). This new ANS also adds (or references) selected terminology defined in T1-developed standards, requirements, and reports.

This new Telecom Glossary 2000 is an outgrowth of the Federal Standard 1037 series, immediately following Federal Standard 1037C, Glossary of Telecommunication Terms , 1996, which was edited by the Institute for Telecommunication Sciences (ITS) in Boulder, Colorado, and reviewed by the National Communications System Member Organizations, by the Federal Telecommunication Standards Committee members, and by representatives from other Federal agencies as well as by representatives from industry and from the general public.

Following the February 2000 approval of T1 Letter Ballot 837, Web-based revision began of the FED-STD-1037C’s 5800 entries, and proposals were developed for the addition of new definitions dealing with new technologies, with security, the Internet, and photonics. Many of the new definitions were drawn from T1 Standards and Reports. [See the ANSI T1 References section following.] The revised glossary was a new endeavor for T1 in that it was developed using exclusively electronic, Web-based and e-mail techniques. Approximately 2300 new entries and revisions were proposed, reviewed, and addressed in "virtual meetings" using an e-mail exploder to discuss definitions and to reach consensus among the 22 members of the T1A1 Ad Hoc Glossary Group. The final product is designed to be a Web-based, search-engine equipped document, rather than a paper document, so that the resulting standard will have wider distribution and greater accessibility with less impact on paper-production resources.

HISTORICAL SUMMARY:

Participants in the Revision

The project was accomplished by a T1A1 Ad Hoc Group comprising interested T1A1 members, contributors from other T1 groups, and members of the FTSC that developed the existing standard. All T1 participants were invited to participate. The National Telecommunications and Information Administration's Institute for Telecommunication Sciences (NTIA/ITS) served as editor for the Telecom Glossary 2000 standard, and is assisting in hosting the Telecom Glossary 2000 Web site.

At the time that the standard was approved, the revision team included the following members (from the glossary e-mail mailing list):

Organization Represented Name of Representative
ABC TV Warner Johnston
SBC Ameritech Lorence F. Brown
Assisi Consulting Don Josephs
Compuserve John Boal
Ensemble Communications, Inc. Marsha Jovanovic
Fluke Corporation Fred Kaudel
Global One Communications, Inc. Paul W. Vince
New Mexico State University E. Johnson
Qwest (formerly U S West) Candace Bruce-Andrews, Gary Stephans
SAIC Henry M. Kluepfel
Siemens Agus Salim
University of Canberra Sakari Mattila
Federal Communications Commission Whitey Thayer
U.S. Department of Agriculture Bill Demarr
U.S. Department of Commerce Jorome T. Gibbon
U.S. Department of Commerce, NTIA John K. Lady
U.S. Department of Commerce, NTIA/ITS Neal Seitz, William Ingram, Evie Gray
U.S. Department of Defense, DISA J. Davies, G. Ring
U.S. Department of Defense, USAF Johan Dekker
U.S. Department of Energy Carol Blackston
U.S. Department of Health and Human Services J. Price
U.S. Department of Interior James Dolezal
U.S. Department of Justice Henry Ickes
U.S. Department of Transportation,
FAA William J. Hughes Technical Center 		James S. Beaty
U.S. Department of Transportation, FHWA William S. Jones
U.S. Department of Treasury Tahir Latif, Gary Allmond

At the time that the standard was approved, the members of T1A1 included the following:

Organization Represented Name of Representative
*** (to be supplied)

At the time that the standard was approved, the members of T1 included the following:

Organization Represented Name of Representative
*** (to be supplied)

Introduction

1. Scope

This document is composed of terms and accompanying definitions that address the disciplines of: telephony, NS/EP (National Security/Emergency Preparedness), NII (National Information Infrastructure), spectrum sharing, radar, radio communications (including HF ALE radio), television (including UHF, VHF, cable TV, and HDTV), facsimile, networks (e.g., intelligent networks, open network architecture, ISDN, broadband ISDN, and network management), fiber optic communications, communications security, data processing, premises wiring, photonics, and telegraphy. The intent is to provide a uniform, up-to-date set of definitions for the general terminology used in telecommunications. The benefits of such a standard include: (a) better communications among U.S. providers and users of telecommunications equipment and services, (b) enhanced understanding of U.S.-developed telecommunications standards, technical reports, technical requirements, contributions, and other specifications in international standardization and trade, and (c) broader public knowledge of telecommunications concepts and advancement of associated public-interest telecommunications capabilities.

The purpose of this standard is to foster technical, interdisciplinary communications, and to disseminate the advances of communications technologies benefitting users, vendors, researchers, and developers. Additionally, this standard provides an authoritative source of definitions for standards developers, teachers, technical writers, and all who are active in the forefront of the telecommunications field.

2. Normative References

The terms and accompanying definitions contained in this standard are drawn from authoritative sources listed in full in the References section below. Major sources of these definitions were

U.S. Government Publications (e.g., the Code of Federal Regulations, Sec. 47) were drawn upon for this and earlier versions of the standard. See the References subsection below.

The complete reference list is given in the References subsection below.

The editors of this standard have rewritten many definitions as deemed necessary either to reflect technology advances or to make definitions, which were phrased in specialized terminology, more understandable to a broader audience.

3. Use

The terms and definitions contained herein are offered as an American National Standard to be used in a manner consistent with such standards.

Nearly all terms are listed alphabetically; a few exceptions to this rule are (1) the family of networking topologies, which are grouped under the definition of "network topology," and (2) the family of dispersion terms, which are grouped under the definition of "dispersion." In all cases, ample cross references guide the reader to the location of the definition, while hyperlinks and the search engine provide instant access to the text of all entries. Term names containing numerals are alphabetized as though the numbers were spelled out; thus, "144-line weighting" will appear in the "O" portion of the alphabet between the terms "on-board communication station" and "one-part code," since "144-line" is pronounced as if it were spelled "one-forty-four line. . . ." For user convenience, exceptions to the alphabetical-sequence rule are taken for entries comprising numerically consecutive terms, e.g. , "digital signal 0," . . . "digital signal 4," which are grouped numerically following the "digital signal" entry.

An abbreviation for the term name often appears in parentheses following the term name. When both the abbreviation and the spelled-out version of a term name are commonly used to name an entity defined in this glossary, the definition resides with the more commonly used version of the term name. For example, the definition of "decibel" resides under the term name "dB." Hyperlinked cross references provided the user with easy access in all cases.

When more than one definition is supplied for a given term name, the definitions are numbered, and the general definition is given first. Succeeding definitions are often specific to a specialized discipline, and are usually so identified. No ranking or importance is implied in the numbered sequence of definitions.

Notes appended to the defining phrase are expository or tutorial in nature. Notes and cross references apply only to the immediately preceding definition, unless stated otherwise.

Several types of cross references are used:

Term names that are semantically incorrect, that have been replaced by recent advances in technology, or that have definitions that are no longer applicable, are designated as "deprecated." In such case, the reader is referred to current term names, where applicable.

Use of definitions that carry the source citations "47CFR," "47 CFR 36-A," "RR," or "NTIA," is addressed with a cautionary note in this Foreword below.

Figures have been added to many definitions throughout the glossary to illustrate complex concepts or systems that are defined herein. A figure that is relevant to more than one definition has been inserted, for convenience, beneath all relevant definitions in this glossary. For example, the definition of "uplink" contains a figure that shows both an uplink path and a downlink path. The definition of "downlink" includes the same figure.

Video clips have been added to illustrate definition of complex video elements or attributes.

Audio clips have been added to illustrate definitions of audio concepts.

Appendix A contains a list of abbreviations used in this glossary. In that list, defined terms are hyperlinked to their respective definitions.

This standard incorporates and supersedes FED-STD-1037C, Glossary of Telecommunication Terms, June 1996.

Caution: Users of this standard are cautioned that in cases where term names or definitions have been extracted verbatim from sources embedded in law (e.g., Title 47, Code of Federal Regulations, [47CFR], or international treaty), in those cases, the wording of these legal definitions may have changed in the source documents [e.g., by legislative action] after this Telecom Glossary 2000 was completed. To be absolutely up to date, the user is advised to take the following cautionary measures: in any context where a CFR definition (or a Radio Regulations [RR] definition) may apply or may have legal ramifications, the user is advised to

4. Links

Nearly all hyperlinks, within definitions in this glossary, connect internally to other related glossary definitions. Few hyperlinks were created that point to Web documents outside the glossary.

The internal hyperlinks within definitions in this glossary were all generated automatically using program scripts. When the script found an occurrence of a related term name, within the text of a definition, it created a hyperlink from the first occurrence of that term name. Further occurrences of that name, within that definition, were not hyperlinked.

The program script automatically created links primarily on the basis of character-string matching, without applying human logic. As a result, some hyperlinks were created that point to term names that are not appropriate for that particular definition's usage.

5. Effective Date

The standard is effective 180 days following the date of its approval.

6. Changes

When an individual considers that this standard requires insertion of deletion of a definition, a statement citing the essential need for that addition or deletion shall be sent to the T1A1 technical subcommittee Chair for forwarding to the editor(s) of the next revision.

References

LEGEND and KEY to Source Citations

Citation Meaning
[ ] (no source citation) These definitions are from two major sources:
(a) FED-STD 1037C 1996, Glossary of Telecommunication Terms, and
(b) a body of definitions proposed and reviewed by industry standards workers.
[After...] Definitions with a source citation "[After...]" (as in "[After Weik '89]") are the responsibility of the Ad Hoc group editing the glossary rather than the responsibility of the authors of the cited material.
2196 Definitions extracted verbatim from MIL-STD-2196 (SH), Glossary, Fiber Optics (Jan. 1989). The citation "[After 2196]" indicates editing of the source definition. All such editing is the responsibility of the editors of this T1 standard and not the cited document.
2382-35 Committee Draft 12/15/98 of ISO/IEC 2382-35 on Networking.
2382-8 ISO/IEC 2382-8, Information Technology - Vocabulary: Control, integrity, and security, 1998.
ANSDIT The American National Standard Dictionary for Information Technology (ANSDIT), ANSI X3.197-1996, and the draft of the Millennial Edition of ANSDIT 2000.
Bahorsky Bahorsky, R. (ed.) (1998), Official Internet Dictionary, Government Institutes. [Used with written permission of the holder of the copyright.]
CC Common Criteria for Information Technology (IT), Security Evaluation, August 1999, CCIMB-909-031. [Inspiration from this source resulted in definitions that were rewritten to fit the Telecom Glossary 2000 format and purpose.]
CCITT/CCIR or ITU-T/ITU-R Recommendations and other documents from the ITU-T and ITU-R, formerly the Consultative Committee for Telegraph and Telephone, and the Consultative Committee for Radio. The "CCITT" and "CCIR" labels are retained in this glossary in some cases because some of the cited documents have not been reissued and given a new name. In other cases, the more current "ITU-T" or "ITU-R" label is used for consistency within this glossary, even though the "CCITT" or "CCIR" label may be more formally accurate. This dual-citation approach is used because some definitions in this glossary are based on a harmonization of several closely related standards reflecting a broad context of different standards groups, and other definitions refer to specific international standards.
47CFR ... Definitions extracted verbatim from the Code of Federal Regulations, Sec. 47, Telecommunications (rev. Oct. 1, 1987, Oct. 1988 & ff.). Caution: Users of this standard are cautioned that-in cases where term names or definitions have been extracted verbatim from sources embedded in law, (e.g., Title 47, Code of Federal Regulations, [47CFR], or international treaty) in those cases, the wording of these legal definitions may have changed in the source documents [e.g., by legislative action] after this T1 standard was sent to press. To be absolutely up to date, the user is advised to examine the most recent of these legislative or treaty source documents.
47 CFR 36-A Definitions extracted verbatim from the Code of Federal Regulations, Ch. 1, Sec. 47, Part 36, Appendix-Glossary, Oct. 1, 1999 edition.
FAA Beaty, James S., Glossary of Optical Communication Terms, April 1991, DOT/FAA/CT-TN91-9, U.S. Department of Transportation, Federal Aviation Administration, Technical Center, Atlantic City International Airport, NJ 08405.
FRMR Federal Information Resources Management Regulation 201-13-103.
FCC FCC Glossary of Telecommunications Terms, on the Web at http://www.fcc.gov/cib/handbook.html.
FED-STD-1045A Telecommunications: HF Radio Automatic Link Establishment (1993).
FP Definitions extracted from Federal Information Processing Standard Publication (FIPS PUB) 11-3, American National Standard Dictionary for Information Systems, which adopts ANSI X3N-1990 (with unchanged title), and which is superseded by ANS X3.172, 1996, American National Standard Dictionary of Information Technology (ANSDIT).
IEC IEC (1999), TC Newsletter, No. 6, February. [IEC, 3 rue de Varembé, P.O. Box 131, 1211 Geneva 20, Switzerland.] (Modified by the Ad Hoc Group.)
IEEE-100-1992 The New IEEE Standard Dictionary of Electrical and Electronics Terms (1992), 5th Edition, IEEE, Inc., 345 East 47th Street, New York, NY 10017-2394.
INFOSEC-99
or NIS 		National Information Systems Security (INFOSEC) Glossary, NSTISSI No. 4009, January 1999 (Revision 1). Caution: The T1 Technical Subcommittee and Ad Hoc committee used the most recent version of the NSTISSI 4009 document that was available at the time that this T1 document was being developed (Nov. 1999 to October 2000). However, the NSTISSI document may have changed asynchronously with this T1 standard, and those NSTISSI definitions may have been amended. The NSTISSI source document will be updated on the Internet. For the latest version of the NSTISSI No. 4009 Glossary, the reader must access the document on the Internet. For hard copy of the 4009 Glossary, write NSA at Ft. Meade, MD. The user may wish to enhance his/her researches into definitions by reviewing the newer version of the 4009 glossary. The changes on 4009 on the Internet do not, per se, revise this T1 standard.
ITU-T
or ITU/R 		Recommendations and other documents from the ITU-T or ITU-R, formerly the Consultative Committee for Telegraph and Telephone, and the Consultative Committee for Radio. The "CCITT" and "CCIR" labels are retained in this glossary in some cases because some of the cited documents have not been reissued and given a new name. In other cases, the more current "ITU-T" or "ITU-R" label is used for consistency within this glossary, even though the "CCITT" or "CCIR" label may be more formally accurate. This dual-citation approach is used because some definitions in this glossary are based on a harmonization of several closely related standards reflecting a broad context of different standards groups, and other definitions refer to specific international standards.
JP1 or
JP 1-02		 Telecommunications definitions extracted from Joint Chiefs of Staff Publication No. 1-02, Department of Defense Dictionary of Military and Associated Terms (1999).
JSB Beaty, James S., U.S. Department of Transportation, Federal Aviation Administration, William J. Hughes Technical Center, Atlantic City International Airport, NJ 08405. E-mail communication to the Glossary Ad Hoc Group.
Mattila Mattila, S. (1998), Secure Electronic Transaction Terms, e-mail to the Ad Hoc Glossary Group. [Used with written permission of the holder of the copyright.]
MS Microsoft Press Computer Dictionary, 3rd ed. 1997 [Redmond, WA: Microsoft Press. ISBN 1-57231-743-4, 704 pp.] [Substantially modified by the Ad Hoc Group.]
NECA/FCC-5 National Exchange Carrier Association, Inc., Tariff No. 5 filed with the FCC on March 9, 2000.
NTIA Definitions extracted verbatim from the NTIA Manual of Regulations and Procedures for Federal Radio Frequency Management . [The NTIA Manual may be purchased at the U.S. Department of Commerce, NTIA, Office of Spectrum Management, Room 1605, Herbert C. Hoover Bldg., 14th and Constitution, N.W., Washington, DC 20230.]
NIS The pre-1999 edition of INFOSEC-99. (See reference for INFOSEC-99 above)
Pacific Newsbytes Pacific Newsbytes Vol. 3, No. 10, Dec. 1998, & Vol. 4, No. 1, Jan. 1999.
RR Definitions extracted verbatim from the International Radio Regulations, Malaga-Torremolinos (Oct. 1984, ref. 1985).
Silicon Silicon Graphics (1998), Film & Video Glossary, 39 pp. [Inspiration from this glossary generated definitions that were significantly modified by the Ad Hoc group to conform to the purpose of the Telecom Glossary 2000. ]
SMPTE Society of Motion Picture and Television Engineers, a 60-page glossary, Proposed SMPTE Engineering Guideline, Annotated Glossary of Essential Terms for Electronic Production, (1998). [Inspiration from this glossary generated definitions that were significantly modified by the Ad Hoc Group to suit the purposes of the Telecom Glossary 2000. ]
Sullivan Sullivan, T.F.P. (ed.), Official Telecommunications Dictionary, (1997), Government Institutes.
T1 Draft of ANSI T1A1.5 Glossary, Document #T1A1.5/94-137, July 29, 1994. S. Wolf (ed.). [For a complete bibliography of T1 Standards and Reports used in this glossary, see the ANSI T1 References List below.] NOTE: The T1-cited terms defined herein are as used in the standards developed by Committee T1. The same terms may be used in a different context with a different meaning.
After Weik ’89 Use of this source citation acknowledges that the cited information is from Communications Standard Dictionary, 2nd ed., Dr. M. Weik, 1989 (Van Nostrand Reinhold Co., New York, NY), with the written permission of the holders of the copyright. These definitions are sometimes verbatim, but in most cases have been abbreviated or edited.
Weik Weik, M. H., Communications Standard Dictionary, 1997, Chapman & Hall. Used with the written permission of the holder of the copyright.
X. ... Definitions cited "[X. ...]" or "[After X. ...]" were obtained from the X9 Accredited Standards Committee. The definitions have been rewritten for the broader audience. The X9 documents used in this glossary are listed below.
Note 1: Appreciation is proffered to the Telecommunications Industry Association for permission to include definitions from ANSI/EIA/TIA-440A, Fiber Optics Terminology (1988). These entries are not source-cited herein because of extensive editorial rewriting by the editors of this document in the interest of making the specialized terminology more understandable to a broad audience. Note 2: Appreciation is extended to working group T1A1.5 for providing their draft glossary of terms and definitions relating to video-quality degradation. Note 3: Appreciation is extended to working group T1X1 for providing their glossary of terms and definitions relating to synchronization and timing.

ANSI T1 References List

Numerical List of ANSI T1 Standards and T1 Reports cited in this glossary:

Note: The T1-cited terms defined herein are as used in the standards developed by Committee T1. The same terms may be used in a different context with a different meaning.

Standard/Report Number, Title of the ANSI T1 Standard ("R" = reaffirmed)

T1 TECHNICAL REPORTS

OTHER REFERENCES

X9 References

Web References

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