Axnes Aviation AS
Document number
Revision
Date
AX-PSB-UMAN-0027
Issue E
2015-03-05
Page 3-3
3.6 NIVOX/Push to Talk (PTT) Operation
When a helmet/headset is connected to the MP20, the NIVOX (Non Interrupted Voice
Operated X-mission) or PTT function is automatically activated according to the default
setting
5
.
In Axnes
’ patented NIVOX mode, transmission will be voice activated, and transmission will
stay open for a pre-programmed hang time after voice audio input has ended. The MP20 will
monitor the ambient noise levels and use this to differentiate voice input from ambient noise.
This feature will allow the Polycon MP20 to adapt and operate in NIVOX mode even in high
noise environments far better than traditional VOX systems.
In PTT mode the transmission is controlled by pressing the large front PTT. In both PTT
mode and NIVOX mode,
transmission is indicated in the display as ‘oo’.
When the MP20 operates in NIVOX mode, pressing the front PTT button will change the MP
20 operational mode from NIVOX to PTT mode. In the PTT mode the large front PTT will
have to be pressed in order to start audio transmission.
To move back to NIVOX mode, the side PTT can be pressed twice. The first press will set
the MP20 to Person to Person mode (indica
ted in the display with ‘PP’), and the second will
set the MP20
back to NIVOX (indicated in the display with ‘--’ in standby or ‘oo’ if
transmission is triggered).
When default mode is set to PTT, NIVOX can be activated by press and hold side PTT
button and Front PTT button simultaneously for about 5 seconds, until a short beep is being
heard.
Disconnecting and re-connecting the headset will set the MP20 back to default PTT/NIVOX
setting
5
.
3.7 Person to Person / Casualty Communication mode
Person to Person- or Casualty Communication mode enables the Polycon user wearing a
noise attenuating helmet/headset to hear nearby conversation through the MP20 internal
microphone in the helmet/headset without removing the same.
Setting the MP20 in person to person mode, will disable the NIVOX mode and open the
microphone in the MP20 so that surrounding audio is picked up and transferred to the local
headset. The communication received from the base station in the aircraft, is still audible in
the headset and mixed with the person to person communication.
Any audio picked up in the internal MP20 microphone with the person to person mode
activated is NOT transferred back to the helicopter.
5
Possibility of changing Automatic gain control, default NIVOX/PTT mode, and display orientation is
not available for software version 3.0 and higher. Units with software version 3.0 or higher will show
the software version as two digits in the display at startup.
