Effective Garrison communication in the field can be critical. Many members of the So. Cal. Garrison use FRS (Family Radio System) units to maintain voice comm outside of visual range in the field. On the advice of TR095, I picked up an earbud/microphone unit - a la Radio Shack. The mic is in the earbud piece.
I fasten the FRS radio to my Utility Belt between the holster straps. The mic amplifier is attached inside the upper chest plate (out of sight). The amplifier switch is kept in the OFF/PTT position. VOX is available, however if I were to transmit using the PA system (to ask a civilian for identification) the Garrison would hear my transmission also. To transmit to the Garrison (via FRS) I merely press the PTT switch on the FRS unit itself. The mic amp is therefore passive.
Since my PA system is separate, all I need to do is reach down to the volume/ON-OFF switch located inside my thigh drop box. Turn the PA system off and use the FRS switch to transmit to the Garrison. It works well.