<P> Time zones are usually defined as differing from UTC by an integer number of hours, although the laws of each jurisdiction would have to be consulted if sub-second accuracy was required . Several jurisdictions have established time zones that differ by an integer number of half - hours or quarter - hours from UT1 or UTC . </P> <P> Current civil time in a particular time zone can be determined by adding or subtracting the number of hours and minutes specified by the UTC offset, which ranges from UTC − 12: 00 in the west to UTC + 14: 00 in the east (see List of UTC time offsets). </P> <P> The time zone using UTC is sometimes denoted UTC ± 00: 00 or by the letter Z--a reference to the equivalent nautical time zone (GMT), which has been denoted by a Z since about 1950 . Time zones were identified by successive letters of the alphabet and the Greenwich time zone was marked by a Z as it was the point of origin . The letter also refers to the "zone description" of zero hours, which has been used since 1920 (see time zone history). Since the NATO phonetic alphabet word for Z is "Zulu", UTC is sometimes known as "Zulu time". This is especially true in aviation, where "Zulu" is the universal standard . This ensures all pilots regardless of location are using the same 24 - hour clock, thus avoiding confusion when flying between time zones . See the list of military time zones for letters used in addition to Z in qualifying time zones other than Greenwich . </P> <P> On electronic devices that only allow the current time zone to be configured using maps or city names, UTC can be selected indirectly by selecting Reykjavík, Iceland, which is always on UTC and does not use daylight saving time . </P>

What is the difference between utc and zulu time
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