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 DTG may indicate either the date and time a message was dispatched by a transmitting station or the date and time it was handed into a transmission facility by a user or originator for dispatch.
In US military messages and communications (e.g., on maps showing troop movements) the format is DD HHMM (SS) Z MON YY.
Z references the military identifier of time zone: Example 1: 051100Z represents the 5th day of the current month 11:00 (UTC).
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