ISO
8601:2000(E)
©
ISO
2000
All
rights
reserved
9
4.5
Use
of
separators
When
required,
the
following
characters
shall
be
used
as
separators:
[-]
(hyphen):
to
separate
the
time
elements
"year"
and
"month",
"year"
and
"week",
"year"
and
"day",
"month"
and
"day",
and
"week"
and
"day";
NOTE
1
The
hyphen
may
also
be
used
to
indicate
omitted
components.
[:]
(colon):
to
separate
the
time
elements
"hour"
and
"minute",
and
"minute"
and
"second".
[/]
(solidus):
to
separate
the
two
components
in
the
representation
of
time-intervals
or
recurring
time-intervals.
[#]
(number
sign):
to
separate
in
the
representation
of
a
recurring
time-interval
the
time-interval
and
the
recurrence
factor.
NOTE
2
Representations
defined
by
this
International
Standard
also
make
use
of
the
decimal
separator.
4.6
Truncation
By
mutual
agreement
of
the
partners
in
information
interchange
it
is
permitted
to
omit
higher
order
components
(truncation)
in
applications
where
their
presence
is
implied.
The
addition
of
a
single
hyphen
in
place
of
each
omitted
component
may
be
necessary,
to
avoid
risk
of
misinterpretation.
These
leading
hyphens
may
be
omitted
in
the
applications
where
there
is
no
risk
of
confusing
these
representations
with
others.
Truncation
should
only
be
used
in
situations
where
the
application
ensures
that
the
value
of
the
omitted
components
can
be
inferred
unequivocally
by
all
communicating
parties.
NOTE
Insufficient
attention
to
this
requirement
may
give
rise
to
problems
like
the
"millennium
bug".
When
truncated
representations
are
used
provisions
should
be
made
to
prevent
confusion
of
the
truncated
representations,
with
other
date
and
time
representations
used
by
the
application.
4.7
Expansion
By
mutual
agreement
of
the
partners
in
information
interchange
it
is
permitted
to
expand
the
component
identifying
the
calendar
year,
which
is
otherwise
limited
to
at
most
four
digits.
This
enables
reference
to
dates
and
times
in
calendar
years
outside
the
range
supported
by
complete
representations,
i.e.
before
the
start
of
the
year
[0000]
or
after
the
end
of
the
year
[9999].
When
expanded
representations
are
used,
provisions
should
be
made
to
prevent
confusion
of
the
expanded
representations,
with
other
date
and
time
representations
used
by
the
application.
4.8
Leading
zeros
Each
date
and
time
component
in
a
defined
representation
has
a
defined
length,
and
leading
zeros
shall
be
used
as
required.
4.9
Mutual
agreement
Some
of
the
representations
identified
in
this
International
Standard
are
only
allowed
by
mutual
agreement
of
the
partners
in
information
interchange.
Such
agreement
should
ensure
that
fields
in
which
the
representation
may
occur
is
not
allowed
to
hold
other
representations
that
cannot
be
unambiguously
distinguished
from
the
agreed
representation.
