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). The order in which these elements are presented may vary. The DTG is usually placed in the header of the message. One example is "16:45 Dec 14, 2019 (UTC)".
The DTG may be used as a message identifier if it is unique for each message.
Military Date Time Group
A form of DTG is used in the US Military's 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 HHMMZ MON YY. Although occasionally seen with spaces, it can also be written as a single string of characters.
Example 1: 091630Z JUL 11 represents (Jul) 09 16:30 Jul 2011 (UTC).
Example 2: 141645Z Dec 19 represents (Dec) 14 16:45, Dec 2019 (UTC).
- TM 20-205, the Dictionary of United States Army Terms (1944)
- ACP 121(I) p 3-7