Northern Airborne Technology AMS42 - Manual (Page 59)

SM19 Rev. 4.00 AMS42/44 Dual Channel Audio Controller Manual
Nov 21, 2003 Page 3-5
ENG-FORM: 806-0102.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
3.5.1 ICS Modes of Operation
Intercom system (ICS) audio may be implemented in three modes between users; LIVE
(on constantly), VOX (voice activated), or KEYED (active only when switched by ICS
PTT switch). The ICS mode is selected by the ICS Mode control (see below). It is
common to use the LIVE mode during ground operations, start-up, etc., and to use VOX
or KEYED operation if conditions are so noisy that ‘pilot fatigue’ will result.
ICS Mode Control
ICS mode selection is made by positioning the ICS Mode control for the desired operation.
KEYED ICS (PTT Operation)*
ICS Mode Control set fully counter-clockwise into the switch detent.
LIVE (Hot Mic Operation)
ICS Mode Control set fully clockwise.
VOX (Voice Activated)
ICS Mode Control set fully clockwise, then slowly rotated counter-clockwise until
the intercom just becomes ‘quiet’. This setting will vary with ambient noise
conditions, and the quality and number of microphones connected in the system.
* KEYED operation is inherent to the pilot and copilot microphone circuits only.
3.5.2 Passenger ICS Operation
Passenger ICS audio is LIVE when the controller is in the LIVE or KEYED mode of ICS
operation and are VOX triggered when a VOX setting is selected. Note that the
passengers are always LIVE unless interrupted by an in-line PTT cord, or the controller
is set for VOX operation.
Passenger and copilot (observer) operations can be maximized by using PTT type cord
assemblies designed for use with NAT audio controllers.
CAUTION: Ensure that all PTT type cord assemblies have properly shielded mic and
phone wiring, or ‘crosstalk’ will occur.