IS 7900: Data Elements and Interchange Formats - Information Interchange - Representation of Dates and Times

2007·2.5 MB·English

by  Bureau of Indian Standards

इंटरनेट मानक
Disclosure to Promote the Right To Information
Whereas the Parliament of India has set out to provide a practical regime of right to
information for citizens to secure access to information under the control of public authorities,
in order to promote transparency and accountability in the working of every public authority,
and whereas the attached publication of the Bureau of Indian Standards is of particular interest
to the public, particularly disadvantaged communities and those engaged in the pursuit of
education and knowledge, the attached public safety standard is made available to promote the
timely dissemination of this information in an accurate manner to the public.
“जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ”
Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru
“The Right to Information, The Right to Live” “Step Out From the Old to the New”
IS 7900 (2007): Data Elements and Interchange Formats -
Information Interchange - Representation of Dates and Times
[MSD 5: Documentation and Information]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee””
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”

IS 7900:2007
iSO 8601:2004

pi%?w
( t7%’??7 )
Indian Standard
DATA ELEMENTS AND INTERCHANGE FORMATS —
INFORMATION INTERCHANGE —
REPRESENTATION OF DATES AND TIMES
(Third Revision )
[es 01.140.30

@ BIS 2007

BUREAU OF iNI)l AN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002
October 2007 Price Group 11
Documentation and Information Sectional Committee, MSD 5
NATIONAL FOREWORD
This Indian Standard (Third Revision) which is identical with ISO 8601 : 2004 ‘Data elements and
interchange formats — Information interchange — Representation of dates and times’ was adopted
by Bureau of Indian Standards on the recommendation of the Documentation and Information
Sectional Committee and approval of the Management and Systems Division Council.
This standard, originally published in 1976, was based on ISO 2014:1976, In the first revision of this
standard in 1999, ISO 8601 : 1988 was adopted and Technical Corrigendum 1 to the above
International Standard was also incorporated. In the second revision of this standard in 2001, ISO
8601 : 2000 was adopted, This third revision of IS 7900 has been necessitated because of the
publication of ISO 8601:2004 which cancels and replaces ISO 8601:2000.
The text of ISO Standard has been approved as suitable for publication as an Indian Standard without
deviations. Certain conventions are, however, not identical to those used in Indian Standards.
Attention is particularly drawn to the following:
a) Wherever the words ‘International Standard: appear referring to this standard, they should
be read as ‘Indian Standard’,
b) Comma (,) has been used as a decimal marker, while in Indian Standards, the current
practice is to use a point (.) as the decimal marker.
In this adopted standard, reference appears to certain International Standards for which Indian
Standards also exist. The corresponding Indian Standards, which are to be substituted in their
respective places, are listed below along with their degree of equivalence for the editions indicated:
International Standard Corresponding Indian Standard Degree of
Equivalence
ISO 31-0 : ~992 Quantities and units: IS 1890 (Part O) : 1995 Quantities and Identical
Part OGeneral principles units: Part OGeneral principles
ISO 31-1 : 1992 Quantities and units: IS 1890 {Part 1) : 1995 Quantities and do

Part 1Space and time units: Part 1 Space and time (third

revision)
LSO/lEC 646 : 1991 Information IS 10315: 1997 Information technology do
technology — ISO 7-Bit coded character — 7-Bit coded character set for
set for information interchange information interchange (first revision)
The technical committee responsible for the preparation of this standard has reviewed the provisions
of following publications referred in this adopted standard and has decided that they are acceptable
for use in conjunction with this standard:
International Standard Title
ISO 19018:2004 Ships and marine technology — Terms, abbreviations, graphical symbols
and concepts on navigation
IEC 60050-111: 1996/ International Electrotechnical Vocabulary — Chapter 111: Physics and
Amd.1 chemistry — Time and related concepts
IEC 60050-713:1998 International Electrotechnical Vocabulary — Part 713:
Radiocommunications: transmitters, receivers, networks and operation
Rec. ITU-R TF.460-5 Standard-frequency and time signal emissions ‘
ITU-T S,1 International Telegraph Alphabet No. 2
Annexes A and B of this Indian Standard are for information only and do not form a part of the
standard,
IS 7900:2007
!!308601 :2004
Indian Standard
DATA ELEMENTS AND INTERCHANGE FORMATS —
INFORMATION INTERCHANGE —
REPRESENTATION OF DATES AND TIMES
(Third Revision )
1 Scope
This International Standard is applicable whenever representation of dates inthe Gregorian calendar, times in
the 24-hour timekeeping system, time intervals and recurring time intervals or of the formats of these
representations are included ininformation interchange. Itincludes
— calendar dates expressed interms ofcalendar year, calendar month and calendar day ofthe month;
— ordinal dates expressed interms ofcalendar year and calendar day ofthe year
— week dates expressed interms ofcalendar year, calendar week number and calendar day oftheweek;
— localtime based upon the 24-hour timekeeping system;
— Coordinated Universal Time ofday;
— localtime and the difference from Coordinated Universal Time;
— combination of date and time ofday;
. time intervals;
. recurring time intervals.
This International Standard does not cover dates and times where words are used in the representation and
dates andtimes where characters are not used inthe representation.
This International Standard does not assign any particular meaning or interpretation to any data element that
uses representations in accordance with this International Standard. Such meaning will be determined by the

contextoftheapplication.
2 Terms and definitions
Forthe purposes ofthis document, thefollowing terms and definitions apply.
2.1 Basic concepts
2.1.1
timeaxis
mathematical representation ofthe succession intime of instantaneous events along aunique axis
[IEC60050-111]
2.1.2
instant
pointonthetime axis
[IEC60050-111]
NOTE Aninstantaneouseventoccursataspecificinstant.
IS 7900:2007
1S08601 :2004
2.1.3
time interval
partofthetime axis limited bytwo instants
[IEC60050-111]
NOTE A time intervalcomprisesall instantsbetweenthe two limitinginstantsand, unlessotherwisestated, the
limitinginstantsthemselves.
2.?.4
time scale
system of ordered marks which can be attributed to instants onthe time axis, one instant being chosen asthe
origin
[IEC 60050-111]
NOTE 1 Atimescalemayamongstothersbechosenas:
-- continuous,e.g.internationalatomictime(TAI)(seeIEC60050-713, item713-05-18]
— continuouswithdiscontinuities,e.g. CoordinatedUniversalTime (UTC) dueto leap seconds,standardtimedue‘to
summertimeandwintertime;
— successivesteps,e.g. usualcalendars,wherethetimeaxisissplitupintoasuccessionofconsecutivetimeintervals
andthesamemarkisattributedtoallinstantsofeachtimeinterval;
—- discrete,e.g.indigitaltechniques.
NOTE2 Forphysicalandtechnicalapplications,atimescalewithquantitativemarksispreferred,basedonachosen
initialinstanttogetherwithaunitofmeasurement.
NOTE3 Customarytimescalesusevariousunitsofmeasurementincombination,suchassecond,minute,hour,or
varioustimeintetvalsofthecalendarsuchascalendarday,calendarmonthandcalendaryear.
NOTE4 Atimescalehasa referencepointwhichattributesoneofthemarksofthetimescaletooneoftheinstants,
thusdeterminingtheattributionofmarkstoinstantsforthetimescale.
2.1.5
time point
date
time
mark attributed to anirstant b ymeans ofaspecified time scale

[IEC 60050-1 11]
NOTE1 Onatimescaleconsistingofsuccessivesteps,twodistinctinstantsmaybe expressedbythesametimepoint
(seeNote1oftheterm“timescale”).
NOTE2 Formanytimescaleswithquantitativemariis,thenumericalvalueofthetimepointofaninstantmayalsobe
consideredtobeequaltothedurationbetweentheoriginofthetimescaleandtheconsideredinstant.
NOTE3 InIEC60050-111 thisdefinitioncorrespondswiththeterm“date”.
NOTE-4 Theterm“time”isotlenusedincommonlanguage.However,itshouldonlybeusedifthemeaningisclearly
visiblefromthecontext,sincetheterm“time”isalsousedwithothermeanings.
2.f.6
duration
non-negative quantity attributed to a time interval, the value of which is equal to the difference between the
time points of the final instant and the initial instant of the time interval, when the time points are quantitative
marks
‘[IEC60050-111]
IS 7900:2007
ISO 8601:2004
NOTE1 In the case of discontinuitiesinthe timescale, suchas a leap second orthe change fromwintertimeto
summertimeandback,thecomputationofthedurationrequiresthesubtractionoradditionofthechangeofdurationof
thediscontinuity.
NOTE2 Duration is one of the base quantities in the InternationalSystem of Quantities (ISQ) on which the
internationalSystemofUnits(Sl)isbased,Theterm“time”insteadof“duration”isoftenusedinthiscontext.
NOTE3 Fortheterm“duration”,expressionssuchas “time”or“timeinterval”are oftenused.The term“time”isnot
recommendedinthissense andtheterm“timeinterval”isdeprecatedinthissense toavoidconfusionwiththeconcept
“timeinterval”.
NOTE4 TheS1unitofdurationisthesecond.
2.1.7
nominal duration
duration expressed amongst others inyears, months, weeks ordays
NOTE Thedurationofacalendaryear,acalendarmonth,acalendarweekoracalendardaydependsonitsposition
inthecalendar.Therefore,theexactdurationofa nominaldurationcanonlybeevaluatedifthedurationofthecalendar
years,calendarmonths,calendarweeksorcalendardaysusedareknown.
2.1.8
date
time point representing a calendar day on a time scale consisting of an origin and a succession of calendar
days
NOTE InIEC60050-111 thisdefinitioncorrespondswiththeterm“calendardate”.
2.1.9
calendar date
date representing a particular calendar day by its calendar year, its calendar month and its ordinal number
within itscalendar month
2.1.10
ordinal date
date representing a particular calendar day byitscalendar year and itsordinal number within itscalendar year

2.1.11

week date
date representing a particular calendar day by the calendar year to which its calendar week belongs, the
ordinal number of itscalendar week within that calendar year and itsordinal number within itscalendar week
2.1.12
Coordinated Universal Time
UTC
time scale which forms the basis of a coordinated radio dissemination of standard frequencies and time
signals; itcorresponds exactly in rate with international atomic time, butdiffers from itbyan integral number of
seconds
[IEC60050-713]
NOTE1 UTC isestablishedbytheInternationalBureauofWeightsandMeasures(BIPM, i.e.BureauInternationaldes
PoidsetMesures)andthe InternationalEarthRotationService(IERS). UTCprovidesthebasisofstandardtime,theuse
ofwhichislegal in mostcountries.The 15thConf&ence G6neral des Poidset Mesures (CGPM) (1975) judged in its
Resolution5thatthisusagecanbestronglyrecommended.
NOTE2 UTCisadjustedtoUT1bytheinsertionordeletionofseconds,knownas“leapseconds”
NOTE3 GreenwichMeanTime(GMT) isinternationallyreplacedbyUTC.UTCisoften(incorrectly)referredtoasGMT.
UTC isgenerallyusedbyaviationand maritimenavigationthatalsouseslocalapparenttime and localmean timefor
celestialnavigation(seeISO19018).

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IS 7900:2007
1S08601 :2004
NOTE4 Additionalinformationcanbefoundasfollows:
— theURLfortheITUhttD:/Avww.ituin.t/itudoc/itu-r/rec/tf/index.html
— theURLfortheInternationalBureauofWeightsandMeasureshttD://www.birIm.fr
— theURLfortheInternationalEarthRotationServicehttD://hDiers.obsDmfr..
2.1.13
UTC of day
quantitative expression marking an instant within acalendar day inaccordance with UTC
2.1.14
standard time
time scale derived from coordinated universal time, UTC, bya time shiftestablished in a given location bythe
competent authority
[IEC60050-111]
NOTE Thistimeshiftmaybevariedinthecoumeofayear.
2.1.15
standard time of day
quantitative expression marking an instant within a calendar day by the duration elapsed after midnight inthe
local standard time
.-
[IEC60050-111]
NOTE Standardtimeofdayiscalled“clocktime”inIEC60050-111.
2.1.16
local time
locally applicable time of day such as standard time of day, oranon-UTC based time ofday
.
2.1.17
recurring time interval
series ofconsecutive time intervals ofthe same duration ornominal duration
NOTE Ifthedurationofthetimeintervalsismeasuredincalendarentities,thedurationofeachtimeintervaldepends
onthecalendardatesofitsstartanditsend.

2.2 Time units, nominal du rations and time intervals
2.2.1
second
base unit of measurement of time in the International System of Units (S1)as defined by the International
Committee ofWeights and Measures (CIPM, i.e.Comit4rInternational des Poids et Mesures)
NOTE1 SeealsoISO31-1.
NOTE2 Itisthebaseunitforexpressingduration,
2.2.2
leap second
intentional time step of one second to adjust UTC to ensure appropriate agreement with UT1, a time scale
based onthe rotation ofthe Earth
[Rec. ITU-R TF.460-5]
NOTE An insertedsecondiscelledpositiveleapsecondandanomittedsecondiscallednegativeleapsecond.A
poaitii leapsecondisinsertedbetween[23:59:592] and[24:OO:OOZalndcan be representedas [23:59602]. Negative
teapsecondsare achieved bythe omissionof[23:59:592]. Insertionoromissiontakes place as determinedby IIERS,
normallyon30Juneor31Oecember,butifnecessaryon31Marchor30September.

4
IS 7900:2007
ISO 8601:2004
2.2.3
minute
unitoftime, equal to 60 seconds
[1s0 31-1]
2.2.4
hour
unitoftime, equal to 60minutes
[1s0 31-1]
2.2.5
day
(unit oftime) unitoftime, equal to 24hours
[1s0 31-1]
2.2.6
calendar day
time interval SMing at midnight and ending at the next midnight, the latter being also the starting instant of
thanextc%bdarday “
NOTE1 A@abndardayisoftenalsoreferredtoasday.
N0TE2 w ~ti d aCatandardayis24hours;exceptifmodiiid by:
— theinsertionordetetionofbap seconds,bydecisionoftheInternationalEarthRotationSarvics(IERS), or
— theinse~or dabtionofothertimeintervals,asmaybeprescribedbylocalauthoritiestoalterthetimescaleoflocal
time.
2.2.7
day
(duration) du~”on of.a calendar day
NOTE Theterm“day’app@salsotothedurationofanytimeintewalwhichstartsatacertaintimeofdayatacertain
calendardayanderidsath saw W ofdayatthenextcalendarday.

2.2.8
calendar week
time intetval of seven calendar days starting with a Monday
NOm 1 Acalendarweekisoftenalsoreferredtoasweak.
NOTE2 See3.2.2 forthenamesofthecalendardaysandtheirdaynumbefs,
NOTE3 Acs~ndar weekmaybe identifiedbyi~ ordinalnumberwithinitscalendaryear.
2.2.9
week
duration of acalendar week ,
NOIE Theterm%aek” ap~ies alsototheduratiin ofanytimeintervalwhichstartsat a certaintimeofday ata
Certahcalendardayandendsatthesametimeofdayatthesamecalendardayofthenextcalendarweek.
2.2.10
calendar week number
ordinal number which identifies a ~lendar week within its calendar year according to the rule that the first
calendar week of a year is that one which includes the first Thursday of that year and that the last oalendar
week of a calendar year isthe week immediately preceding thefirst calendar week ofthe next oalendar year

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