Editing Date-time group

{{Short description|Set of characters used to express date and time}}
{{Use dmy dates |date=August 2020}}
In communications messages, a '''date-time group''' ('''DTG''') is a set of characters, usually in a prescribed format, used to express the year, the month, the day of the month, the hour of the day, the minute of the hour, and the [[time zone]], if different from [[Coordinated Universal Time]] (UTC).{{Citation needed|date=July 2013}} The order in which these elements are presented may vary. The DTG is usually placed in the [[header (computing)|header]] of the message. One example is "{{#time:H:i M d, Y}} (UTC)"; while another example is "{{#time:H:i d M Y}}".

The DTG may indicate either the [[calendar date|date]] and time a message was dispatched by a transmitting station or the date and time it was handed into a [[transmission (telecommunications)|transmission]] [[Facility (telecommunications)|facility]] by a [[User (telecommunications)|user]] or originator for dispatch.

The DTG may be used as a message [[identifier]] if it is unique for each message.

== Military Date Time Group ==
{{See also|List of military time zones}}

A form of DTG is used in the [[US Military]]'s [[Defense Message System|message traffic]] (a form of [[Automated Message Handling System]]). In US military messages and communications (e.g., on maps showing troop movements) the format is ''DD HHMM (SS)'' Z'' MON YY''. Although occasionally seen with spaces, it can also be written as a single string of characters. Three different formats can be found:
* {{mono|'''DDHHMMSSZmmmYY'''}} – Full time (used for software timestamps)
* {{mono|'''DDHHMMZmmmYY'''}} – shortened time (used e.g. for timestamps manually written)
* {{mono|'''DDHHMMZ'''}} – short time (e.g. used for planning)
<br>
{{mono|'''Z'''}} references the military identifier of time zone:
* [[UTC]]-12: Y (e.g., Baker Island)
* [[UTC]]-11: X (American Samoa, Niue)
* [[UTC]]-10: W (Honolulu, HI)
* [[UTC]]-9: V (Juneau, AK)
* [[UTC]]-8: U ([[Pacific Standard Time|PST]], Los Angeles, CA)
* [[UTC]]-7: T ([[Mountain Standard Time|MST]], Denver, CO)
* [[UTC]]-6: S ([[Central Standard Time|CST]], Dallas, TX)
* [[UTC]]-5: R ([[Eastern Standard Time (North America)|EST]], New York, NY)
* [[UTC]]-4: Q (Halifax, Nova Scotia)
* [[UTC]]-3: P (Buenos Aires, Argentina; Rio de Janeiro, Brazil)
* [[UTC]]-2: O (South Georgia and the South Sandwich Islands)
* [[UTC]]-1: N (Azores)
* '''[[UTC]]+-0: Z ([[Zulu time]], [[Greenwich Mean Time|GMT]], London)'''
* [[UTC]]+1: A ([[Central European Time|CET]], Stockholm, Copenhagen, Berlin, Paris, Rome, Madrid, Valletta)
* [[UTC]]+2: B ([[Eastern European Time|EET]], Athens)
* [[UTC]]+3: C (Arab Standard Time, Iraq, Bahrain, Kuwait, Saudi Arabia, Yemen, Qatar, as well as Moscow in Russia)
* [[UTC]]+4: D (Oman, the UAE)
* [[UTC]]+5: E (Pakistan, western Kazakhstan, Tajikistan, Uzbekistan, and Turkmenistan)
* [[UTC]]+6: F (eastern Kazakhstan, Bangladesh)
* [[UTC]]+7: G (Thailand)
* [[UTC]]+8: H (Beijing, China, Singapore)
* [[UTC]]+9: I (Tokyo, Japan)
* [[UTC]]+10: K (Brisbane, Australia)
* [[UTC]]+11: L (Sydney, Australia)
* [[UTC]]+12: M (Wellington, New Zealand)

=== Examples ===
Example 1: {{mono|'''051100Z'''}} represents the 5th day of the current month 11:00 (UTC).

Example 2: {{mono|'''091630Tjul11'''}} represents 9 July 2011 4:30 pm (MST).

Example 3: {{mono|'''{{Allcaps|{{#time: dHis\ZMy}}}}'''}} represents the current time of refresh: {{#time:(M) d H:i:s, M Y}} (UTC).

==Sources==
* [https://gwg.nga.mil/ntb/baseline/docs/2500a/2500a.pdf MIL-STD-2500A] {{Webarchive|url=https://web.archive.org/web/20170321080040/http://www.gwg.nga.mil/ntb/baseline/docs/2500a/2500a.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.gwg.nga.mil/ntb/baseline/docs/2500a/2500a.pdf |archive-date=2022-10-09 |url-status=live |date=21 March 2017 }} 12 October 1994

== See also==
*[[Calendar date]]
*[[ISO 8601]]

== References ==
*TM 20-205, the Dictionary of United States Army Terms (1944)
*ACP 121(I) pp.&nbsp;3–7
{{reflist}}

==External links==
{{FS1037C|article=date-time group (DTG)|url=http://www.its.bldrdoc.gov/fs-1037/dir-010/_1465.htm}}

{{DEFAULTSORT:Date-Time Group}}
[[Category:Calendaring standards]]
[[Category:Date and time representation]]