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

3 7 7 3 4

CMD

Mode Control

(ASCII "m")

Data Port Select

(ASCII "d")

Port No.

110

1101101

1100100

000

* Reserved block (set to 000)

FIGURE 17. Data port selection CMD format.

b. Note that the data port selected by a data port selection CMD persists only until the end of the DTM or DBM that immediately follows the data port selection CMD. Thus, a data port selection CMD not immediately followed by a DTM or DBM has no effect.

5.6.4.5 Digital LINCOMPEX zeroization.

The digital LINCOMPEX zeroization command is used to zeroize a digital LINCOMPEX system

(see figure 18). The subcommand position shall be set to 1111111 to initiate zeroization.

3 7 7 7

CMD

1101101

("m" : mode control)

1111010

("z" : LINCOMPEX

zeroize)

Subcommands

FIGURE 18. Digital LINCOMPEX zeroization CMD format.

5.6.4.6 Digital squelch.

The digital squelch command format, figure 19, is used for remote control of a radio's audio output. The second character position shall be set to "q" to indicate a digital squelch command. The third character position (subcommand) shall be set to 1111110 to mute the speaker of a distant radio, or to 0000000 to unmute. A receiving ALE controller that cannot mute the radio speaker should respond with a digital squelch command with the third character position set to

1111111. In other cases, no response is necessary from the receiving ALE controller.

3 7 7 7

CMD

1101101

("m": mode control)

1110001

("q": digital squelch)

(Subcommand)

FIGURE 19. Digital squelch CMD format.