AA86/87 Stereo Intercom Manual
SM48 Rev. 4.00
Page 3-2
Nov 12, 2003
ENG-FORM: 806-0104.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
3.2.1.2
Main Volume Control (
VOL
)
The main Volume control sets the overall Radio/ICS volume level for all headsets.
Rotating the control clockwise increases both the
ICS
(intercom) and radio volumes,
and counterclockwise rotation will reduce these volumes.
It is recommended that the volume be set to the highest
level that any aircraft
occupant
might find comfortable during normal in-cockpit conversation. If this level is too loud for
a particular user, the individual headphone volume controls may be adjusted to a
personally comfortable level.
3.2.1.3
VOX
Control
The VOX Control selects the mode of operation of the intercom microphones. When
the control is in the centre of its range, the intercom is in the VOX mode (voice
activated). As the control is rotated clockwise, the system becomes more sensitive, until
in the fully clockwise position it is in HOT mode (on constantly). As the control is rotated
counterclockwise, the sensitivity decreases.
Each microphone connection is provided with a separate automatically tracking squelch
circuit that requires little adjustment once the original squelch sensitivity is set.
3.2.2 PRIORITY
Control
The
PRIORITY
control is a three position switch that enables the pilot to select between
Headset
, Off and
A/C Radio
to prioritize AA86/87 inputs according to flight conditions.
3.2.2.1
Headset
PRIORITY
When the
PRIORITY
switch
Headset
position is selected, intercom users are given
priority over the aircraft radios. The AA86/87 muting circuit lowers the radio audio and
music level to allow the intra-cabin conversation to be clearly audible. However, since
the radio audio is not completely muted, a 'watch' is maintained on the selected radio.
3.2.2.2
A/C Radio
PRIORITY
When the
PRIORITY
switch is in the
A/C Radio
(aircraft radio) position, the radio audio
has priority over intra-cabin conversation. In this position, the muting circuit lowers the
intercom voice audio whenever an aircraft radio audio is received.
3.2.2.3
OFF
When the PRIORITY switch is in the centre or ‘Off’ position, both the radio audio and
intercom voice inputs have equal priority. Both audio sources are combined and will be
heard equally (unless otherwise set by the AA86/AA87 and Comm radio volume controls). In
this mode, it may be difficult to understand either audio source as both will be heard together.
