Northern Airborne Technology AA85 - Manual (Page 16)

AA85 InterVOX II™ Intercom Manual SM38 Rev. 4.10
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. Ensure
chassis is grounded to provide proper shield terminations.
Ensure microphone and headphone jacks are isolated from the airframe ground.
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 unit to pick up the sound of the motor as ground loop interference.
2.3.3 Notes
The AA85-001 has been manufactured and delivered in both TSO'd (serial # 3000 and
above) and non-TSO'd versions (below serial # 3000). There are critical differences in
the interconnect between the two types, which must be observed to ensure compliance
with the TSO requirements.
TSO'd units are shipped from the factory with 'jack posts' installed at the chassis connector.
The install kit supplied with the AA85 contains a metal 'hood' that must be used on the
airframe connector to ensure compliance with the stated TSO qualification requirements.
Earlier generations of the AA85 (non TSO'd, below s/n 3000) used V5, 'spring lock'
mounting hardware for the chassis connector, with jack posts as an alternative.
If installing this unit into an existing aircraft harness, ensure that the harness connector
does not have the ‘tabs’ shown in figure 1. If the harness connector does have ‘tabs’,
replace the existing harness connector with the one included in the install kit.
Tab
Harness Connector
Figure 1
Important: Although it is possible to install and operate a new TSO'd unit in an
older installation, the system will not be compliant with the stated
TSO requirements due to the differences in the interconnect.
Page 2-2 June 9, 2004
ENG-FORM: 805-0106.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.