MIL-STD-187-721 Interoperability And Performance Standard For Advanced Adaptive Hf RadioThe purpose of this document is to describe the technical parameters for adaptive high frequency HF radio that are more advanced than those described in MIL-STD-188-141. The advanced technology contained in this standard will guide the planning of military adaptive HF radio network technology into the 21st century. To fully understand and utilize this document, it is necessary to refer to portions of MIL-STD-188-141.

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MIL-STD-187-721D

FIGURE 20.  Generic scheduling CMD.

TABLE XIX.  Time codes for scheduling.

b.  In some cases noted in table XVIII (under Date/Time Option), this third character position may be set to 1111111 (all 1's) to specify that the function be performed at the absolute date and time specified in a DATA word that immediately follows the CMD, instead of at a time offset from the end of the transmission.  This date and time DATA word shall be formatted as shown in figure 21.  The Month field shall indicate the desired month (1-12), the Day field the desired day (1-31), depending on the month, the Hour field with the desired hour (0-23), and the Minute field with the desired minute (0-59).  The Z bit shall be set to 0 if the specified hour is Zulu time (UTC), or to 1 if the hour is the local time zone of the sending station.

FIGURE 21.  Date and time word format.

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