1、ANSI INCITS 310-1998 (R2003)(formerly ANSI NCITS 310-1998)for Information Technology Representation of Timefor Information InterchangeCopyright American National Standards Institute Provided by IHS under license with ANSI Not for ResaleNo reproduction or networking permitted without license from IHS
2、-,-,-Copyright American National Standards Institute Provided by IHS under license with ANSI Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSINCITS 310-1998Revision, redesignation, and consolidation ofANSI X3.43-1991 and ANSI X3.51-1994American National Standard
3、for Information Technology Representation of Timefor Information InterchangeSecretariatInformation Technology Industry Council (ITI)Approved February 23, 1998American National Standards Institute, Inc.Copyright American National Standards Institute Provided by IHS under license with ANSI Not for Res
4、aleNo reproduction or networking permitted without license from IHS-,-,-Approval of an American National Standard requires review by ANSI that therequirements for due process, consensus, and other criteria for approval havebeen met by the standards developer.Consensus is established when, in the jud
5、gement of the ANSI Board ofStandards Review, substantial agreement has been reached by directly andmaterially affected interests. Substantial agreement means much more thana simple majority, but not necessarily unanimity. Consensus requires that allviews and objections be considered, and that a conc
6、erted effort be madetowards their resolution.The use of American National Standards is completely voluntary; theirexistence does not in any respect preclude anyone, whether he has approvedthe standards or not, from manufacturing, marketing, purchasing, or usingproducts, processes, or procedures not
7、conforming to the standards.The American National Standards Institute does not develop standards andwill in no circumstances give an interpretation of any American NationalStandard. Moreover, no person shall have the right or authority to issue aninterpretation of an American National Standard in th
8、e name of the AmericanNational Standards Institute. Requests for interpretations should beaddressed to the secretariat or sponsor whose name appears on the titlepage of this standard.CAUTION NOTICE: This American National Standard may be revised orwithdrawn at any time. The procedures of the America
9、n National StandardsInstitute require that action be taken periodically to reaffirm, revise, orwithdraw this standard. Purchasers of American National Standards mayreceive current information on all standards by calling or writing the AmericanNational Standards Institute.American National StandardPu
10、blished byAmerican National Standards Institute, Inc.11 West 42nd Street, New York, NY 10036Copyright 1998 by Information Technology Industry Council (ITI)All rights reserved.No part of this publication may be reproduced in anyform, in an electronic retrieval system or otherwise,without prior writte
11、n permission of ITI, 1250 Eye Street NW, Washington, DC 20005. Printed in the United States of AmericaCopyright American National Standards Institute Provided by IHS under license with ANSI Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-iContentsPageForeword ii1 S
12、cope, purpose, and application 12 Definitions. 13 Specificiations. 24 Combinations of date and time representation. 4AnnexesA Relationships between representations of time for information interchange,Daylight Saving Time, and U.S. Time Zone code sets . 5B Explanation of designation civil time. 8C So
13、urces of time information 9D Bibliography 11Copyright American National Standards Institute Provided by IHS under license with ANSI Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-iiForeword (This foreword is not part of American National Standard NCITS 310-1998.)T
14、his standard provides a single, unambiguous format for representing time in infor-mation interchange. Time refers to an instant in the time continuum of a day. Thebasic representation of time for information interchange specified in this standard isHHMMSS.ssss plus a time-differential from coordinat
15、ed universal time, where HHrefers to the hour in the twenty-four-hour time-keeping system, MM refers to theminute, SS refers to the second, and ssss refers to the decimal second (to whatev-er number of significant digits may be necessary). This standard will be of interest toinformation and data man
16、agers, data administrators, and others responsible for mak-ing data sharable. It will also be of interest to manufacturers of repository and CASEtool products.This standard addresses the need for a single standard for information interchange oftime data. It combines two previous American National St
17、andards on time in orderto reduce potential confusion possible with two separate standards relating to time.A single standard for representation of time that incorporates all relevant aspects ofthe representation of time is desirable in order to reduce potential confusion in inter-change of time inf
18、ormation. Other standards for representing time in information in-terchanges contain various options for interchange of time; thus, potential confusioncan arise as to the exact format being used for interchange of time. This standardeliminates such potential confusion.This standard was developed wit
19、hin the usual consensus process of ANSI standardscommittees. Knowledgeable experts from the U.S. Naval Observatory, the NationalInstitute for Standards and Technology, Lawrence Berkeley Laboratory, and other or-ganizations participated in the development of this standard. Issues were fully dis-cusse
20、d, with pros and cons identified, and votes taken to resolve them.This standard contains four annexes, Annex A is normative and is considered part ofthis standard. The remaining annexes are informative and are not considered part ofthe text.Requests for interpretation, suggestions for improvement or
21、 addenda, or defect re-ports are welcome. They should be sent to the National Committee for InformationTechnology Standards (NCITS), ITI, 1250 Eye Street, NW, Suite 200, Washington,DC 20005.This standard was processed and approved for submittal to ANSI by NCITS. Com-mittee approval of this standard
22、does not necessarily imply that all committee mem-bers voted for its approval. At the time it approved this standard, NCITS had thefollowing members:Karen Higginbottom, NCITS Chair (Acting)Karen Higginbottom, NCITS Vice-ChairMonica Vago, NCITS SecretaryOrganization Represented Name of Representative
23、AMP, Inc. John HillCharles Brill (Alt.)Apple Computer, Inc. David K. Michael Jerry Kellenbenz (Alt.)AT it does not describe how time is determined. This standard was not designed for(nor does it preclude) usage by humans as input to, or output from, data systems.1.2 PurposeThe purpose of this Americ
24、an National Standard is to provide a single, unambiguous standard means ofrepresenting time for interchange of time information among data systems.1.3 ApplicationThe representation of time specified in this standard is compatible with other national and internationalstandards. The representation spe
25、cified by this American National Standard is in the basic format of“differences between civil time and Coordinated Universal Time” (as described in ISO 8601:1988), with anextension to represent designated civil time, which is defined to have the same numerical representationacross all time zones.1.4
26、 CancellationsThis standard cancels and replaces American National Standard for Information SystemsRepresentations of Local Time of Day for Information Interchange (ANSI X3.43-1991) and AmericanNational Standard for Information Systems Representations of Universal Time, Local Time Differentials,and
27、United States Time Zone References for Information Interchange (ANSI X3.51-1994).2 DefinitionsFor this American National Standard, the following definitions apply:2.1 time: “In English time is used to specify an instant (time of day)” ITU-R Recommendations, 1994TF Series Volume, Time Signals and Fre
28、quency Standards Emissions (Recommendation 686, Glossary).A particular point in the stream of time at a particular place (which may or may not be specified in terms ofa particular date): A specific hour, or minute, or second, or fraction of a second in a day at a specificplace.2.2 second: “The durat
29、ion of 9 192 631 770 periods of the radiation corresponding to the transitionbetween the two hyperfine levels of the ground state of the cesium atom-133.” (XIIIeConference Generaledes Poids et Mesures, 1967). Ordinarily, a second is one-sixtieth of a minute.2.3 leap second: A second of time intentio
30、nally inserted in or deleted from the UTC time stream to keepit approximately compatible with the rotation of the Earth. An inserted second is called a positive leapsecond and an omitted second is called a negative leap second. For the purposes of this standard, aCopyright American National Standard
31、s Institute Provided by IHS under license with ANSI Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSI NCITS 310-19982positive leap second is labeled “60” and a negative leap second is labeled “58” (there being no secondwith the label “59” in a minute with a nega
32、tive leap second).2.4 minute: Sixty seconds, each labeled consecutively in the 24-hour timekeeping system from 0 through59 beginning with the start of the first second after the beginning of the minute. Ordinarily, a minute isone-sixtieth of an hour.NOTE: A minute that contains a leap second will ha
33、ve 61 or 59 seconds, depending upon whether the leapsecond is positive or negative, respectively.2.5 hour: Sixty minutes, each labeled consecutively in the 24-hour timekeeping system from 0 through 23beginning with the start of the first minute after the beginning of the hour. Ordinarily, an hour is
34、 onetwenty-fourth of a day.NOTE: An hour that contains a leap second will have one extra or one less second, depending uponwhether the leap second is positive or negative, respectively.2.6 date: A particular day within a Gregorian calendar month, consisting of 24 hours in the 24-hourtimekeeping syst
35、em. Ordinarily, a date is specified by a year, a month, and the sequential day within amonth (see ANSI X3.30).NOTE: A day that contains a leap second will have one extra or one less second, depending upon whetherthe leap second is positive or negative, respectively.2.7 designated civil time: A time
36、whose representation is independent of all time differentials from UTC.Example: 9 oclock in the morning civil time in any time zone, adjusted for Daylight Saving Time, ifappropriate.2.8 civil time: The time defined in a region by the civil authorities there, adjusted for Daylight SavingTime, if appr
37、opriate.2.9 Daylight Saving Time: An instant in civil time represented with an adjustment specified by theUniform Time Act of 1965, as amended: “During the period commencing at 2 a.m. on the first Sunday inApril of each year and ending at 2 a.m. on the last Sunday in October, the standard time is ad
38、vanced onehour except in those states that have by law exempted themselves from observance of advanced time.”NOTE: Standard time as used in this quotation is taken to refer to civil time for the purposes of this stan-dard.2.10 coordinated universal time (UTC): “The official coordinate time scale for
39、 the Earth defined on therotating geoid.” Rec. ITU-R TF.1010, Relativistic Effects in a Coordinate Time System in the Vicinity ofthe Earth. “The time scale, maintained by the Bureau International des Poids et Mesures (BIPM), and theInternational Earth Rotation Service (IERS), which forms the basis o
40、f a coordinated dissemination ofstandard frequencies and time signals” Rec. 686, Glossary.2.11 Time-differential-from-UTC: The difference in hours and minutes between Civil time and UTC.3 Specifications3.1 Time for information interchangeTime is to be represented as civil non-daylight saving time pl
41、us a time-differential-from-UTC in the following “24-hour clock” format: HHMMSS.ssss(+, - , or *) hhmm,whereHH represents hours, MM represents minutes, SS represents seconds, ssss represents decimalfractions of a second with an unlimited number of significant digits,Copyright American National Stand
42、ards Institute Provided by IHS under license with ANSI Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSI NCITS 310-19983and“+” or “-” represents positive or negative time differentials (respectively) from UTC,or“*” represents all time differentials from UTC worl
43、dwide,withhhmm representing hours and minutes time-differential-from-UTC.NOTE: The parenthesis symbols are not part of the representational format, but are used to indicate thatrepresentations of time will use one of the three symbols. Example: 39 minutes and 25.6 seconds past 7 oclock EST civil tim
44、e in the afternoon of 31 December in Philadelphia, Pennsylvania is a point in non-daylight saving time represented for interchange purposes as 193925.6-0500.Example: Designated civil time for 7 oclock in the afternoon civil time in every time zone in the world, with one-decimal-second significant di
45、git, is represented as 190000.0*NOTE: Time-differential-from-UTC is not present in the representation of a designated civil time 3.2 Sequencing of time componentsThe sequencing of time components shall be from high order to low order (left to right): hour of the day(HH), minute of the hour (MM), sec
46、ond of the minute (SS) with decimal seconds as appropriate: ssss,followed by the time-differential-from-UTC. Leading zeroes in each time component are required.Truncation of higher order time components (from left to right) is not permitted.3.3 Degree of specificityThe degree of specificity associat
47、ed with time in specific information interchanges may require truncationof lower order time components (from right to left). Thus, decimal fractions of a second may be dropped,seconds and decimal fractions of a second may be dropped, or minutes and seconds and decimalfractions of a second may be dro
48、pped.NOTE: The time-differential-from-UTC may not be dropped, except in representations of designated civil time as defined below.3.4 Use of separatorsNo separators are allowed in time representations for information interchange, other than those specifiedin this standard.3.5 Representation of secon
49、dsThe beginning of a second within a minute of an hour of a day shall be represented by a two-digit decimalnumber ranging from 00 through 60. When a decimal fraction of a second is specified (ssss), it shall beseparated from the second representation by a decimal point (period) and expressed numerically to theprecision (number of significant digits) desired.NO
