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

An ALE controller receiving this CMD shall tune (if required) and respond as usual, and wait until time "T" for further transmissions. If none are detected, it shall resume scanning. TB7 shall be

set to 0 on transmission, and ignored on reception to limit the waiting period to 32 seconds.

5.6.6.13 Set sounding interval.

a. An ALE controller receiving this CMD shall set the sounding interval on the designated channel to the time in the Time Offset field. TB7 shall be 1 so that the sounding interval is at least 8 seconds. TB1-6 shall not be all 1's.

b. By default, the channel carrying the CMD is the designated channel; however, a different channel may be selected by placing a channel designator (see 5.3) in ALE word bits W4-10 of a DATA word that immediately follows the CMDs. This channel designator shall be

interpreted as an absolute channel number (not as an offset from the channel carrying the

CMD).

5.6.6.14 Tune and wait.

An ALE controller receiving this CMD shall stop scan and tune (if required), but not respond, and wait until time "T" for further transmission. If no transmissions are detected, it shall resume scanning. TB7 shall be set to 0 on transmission, and ignored on reception, to limit the waiting period to 32 seconds.

5.6.6.15 Set slot width.

When sent as part of a transmission that requires slotted responses, this CMD requires that all slots be set to the length in the Time Offset field in the CMD. TB7 shall be set to 0 to limit the slot size to a maximum of 32 seconds. When sent in a transmission that does not require slotted responses, this CMD shall be ignored.

5.6.6.16 Year and date.

This CMD may be used to request and report the date and time. If the third character position in figure 22 is set to all 1's, the CMD is a request for year and date, and shall not be followed by a DATA word. If the third character position contains a 7-bit integer in the range 0-99, this CMD and a following DATA word (formatted in accordance with figure 20) report the year, date, and time. Other values in the third character position are reserved, and shall not be used until standardized.

NOTE: Implementors of this function shall ensure that year 00 is interpreted as greater than year 99 so no difficulties occur when a CMD sent in 1999 schedules an event in 2000.