P139-HD Audio System User Manual
GA063-3 Rev G 08/25/2015
Page 15 of 35
7.4. Intercom Functions
Each headset position has Intercom (ICS) function with PTT and voice-activated keying (VOX). Headset
positions may be separated into zones (e.g. crew and passengers) that may be isolated from each other if
desired. Each control panel has ICS controls for one or more headsets; e.g. a single control panel may
control several passenger headsets.
1.
To enable ICS, press the ICS switch/pot
so that it is in the ‘Out’ position. To disable ICS, press
the ICS switch/pot so that it is in the ‘In’ position.
2.
ICS volume is controlled by adjusting the ICS switch/pot. Turning the pot clockwise increases the
volume.
3.
To key ICS, press the ICS PTT switch assigned to that headset. This control may be on the pilot
cyclic, passenger drop cord, or footswitch depending on aircraft configuration.
4.
ICS may also be keyed by moving the ICS/TX toggle switch on the control panel up to the ICS
position. On control panels serving multiple headsets this function may be disabled.
5.
The VOX is controlled by the VOX switch/pot. Fully clockwise produces hot mic for intercom. Fully
counterclockwise disables VOX, requiring the ICS PTT be keyed to speak over the intercom.
Selecting a position between these extremes sets the VOX threshold. The intercom is keyed
when the audio from the mic exceeds the VOX threshold set.
Pressing the VOX the switch/pot ‘In’
disables VOX.
6.
If configured, the ICS may be split into isolated zones by pressing the ISO button. Headsets in
one zone will hear ICS from all other headsets in that zone, but not from the other zone. Press
the ISO button again to disable isolate. The standard configuration is for two zones. For custom
installations with more than ICS two zones, see the configuration information for that system.
7.5. Call Beep
If the Call Beep button is selected, the crew will hear a periodic beep. This is commonly used to signal
from one Isolated ICS zone to the other.
7.6. Mic Listen
For certain configurations, the Audio System may be set to listen to selected crew mics without that crew
member keying transmit or ICS. This “Mic Listen” operates in a similar way to a receive-only audio device
with a pot/switch.
7.7. Other Functions
Due to the customizable nature of the audio system, specific installations may have functions not covered
in this guide. Consult the individual configuration for your installation to determine if custom functions
have been installed.
