Northern Airborne Technology AA24 - Manual (Page 14)

AA24/AA25 Series Single User Audio Controller Manual SM18 Rev. 4.00
2.3.2 Cautions
In all installations, use shielded cable exactly as shown and ground as indicated. Significant
ground loop and noise problems may result from not following these guidelines.
Do not ground the microphone or headphone jacks.
Do not connect the microphone and headphone shields together.
Use caution when routing microphone and ICS Tie Line wiring, as they are low level
signals prone to coupling from other sources.
Do not take a ground from the instrument panel or similar location that shares a ground
return with a turn and bank, horizon or other motor driven instrument. This may cause
the InterVox unit to pick up the sound of the motor as ground loop interference.
For best results, all headsets/microphones in the system should be of the same type to
avoid VOX problems and uneven volume.
2.3.3 Cabling and Wiring
All unshielded wire should be Tefzel MIL-M-22759/16 or equivalent. For shielded wire
applications, use Tefzel MIL-M-27500 shielded wire with solder sleeves (for shield
terminations) to make the most compact and easily terminated interconnect. Follow the
wiring diagrams in Section 2.6 as required.
Allow 3 inches from the end of the wire to the shield termination to allow the hood to be
easily installed. Note that the hood is a ‘clamshell’ hood, and is installed after the wiring
is complete.
All wiring should be at least 22 AWG, except power and ground lines which should be at
least 20 AWG. Ensure that all ground connections are clean and well secured.
2.3.4
Fuses and Breakers
Power protection should be provided through a 1.0 A breaker, and not attached to any
other existing breaker without additional protection.
2.3.5 Adjustments
See 3D drawing AA24\001\903-0 at the end of this section of the manual for the
adjustment locations.
The unit ships from the factory with all internal adjustments set to the normal test levels.
Once installed in the aircraft, it may be desirable to change some of these settings to
best suit the local operating environment.
Page 2-2 Nov 21, 2003
ENG-FORM: 805-0105.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.