SM48 Rev. 4.00 AA86/87 Stereo Intercom Manual
Nov 12, 2003 Page 2-3
ENG-FORM: 805-0104.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.3.4 Electrical Installation
The AA86/87 Stereo Intercoms employ a single, common ground at Pins 14 and 15.
Ground returns may be tied together and connected to either ground pin.
2.3.4.1 Power
The DC power source (aircraft power or battery, between +10 and +32 volts) must be
connected at Pin 1. Nominal ‘on’ current drain is in the order of 100 ma (175 ma for the
AA87) with peak currents generally less than 0.25 ampere.
2.3.4.2 Microphone
Each microphone (up to six) must be wired to separate mic inputs as follows:
All Models -004 and –006 models only –006 models only
Position Pin # Position Pin # Position Pin #
Pilot 25 Passenger Mic #3 4 Passenger Mic #5 16
Co-Pilot 24 Passenger Mic #4 5 Passenger Mic #6 17
Passenger mics may be wired to any location within the aircraft cabin and are
interchangeable. Pilot and Co-Pilot mic 'identities', however, must be properly
maintained to assure proper transmit audio routing during Push-To-Talk (PTT), Pilot
Isolate, and Fail Safe functions.
2.3.4.3 Headphones
Refer to Interconnect drawing AA86\403-0 for full headphone connection specifics.
The Pilot headphones must be wired to Pins 12 and 13 (left and right channels,
respectively) to assure proper Pilot Isolate and Fail-Safe operation. The Co-Pilot
headphones must be wired to Pins 20 and 21 (left and right channels, respectively) to
assure proper CREW Mode operation (CREW Mode is available only on AA87 Models). All
other headphones should be wired to Pins 8 and 9 (left and right channels, respectively).
The AA86/87 can support up to 20 standard aviation headphones. The Intercom output
is a low impedance source that permits direct connection to consumer stereo
headphones (typically between 8 and 50 ohm) as well as standard aviation headphones
(300 ohm). No matching transformers or other specialized connection systems are
required for any headphone impedance within the range of 4-600 ohm.
Headphones of differing impedances may be mixed (e.g. 8 ohm consumer and 300 ohm
aviation) so long as consideration is given to the fact that the lower impedance
headphones (8 ohm consumer) will produce more output (volume) for a given Intercom
volume setting. Therefore, consumer headphones with built-in volume controls should
be employed.
