Northern Airborne Technology AMS43 - Manual (Page 12)

AMS43 Single Channel Audio Controller
SM59 Installation and Operation Manual
Section 2 Rev: 1.00 Issue 4 Page 2-5
There are numerous manufacturers of in-line PTT drop cords, offering many 'electrical' variations to
accomplish different functions. To meet the operational requirements for headset stations supported by
the AMS43, NAT recommend the dual switch type: a 3-position (momentary/center-off/locking) slider
switch for the ICS functions, and a momentary, push-button switch for the TX functions. Both switches
provide a ‘mic interrupt’ function. The 3-position ICS switch will allow the user to change the switch
settings to match the operational intercom mode that has been selected at the AMS43 (e.g., LIVE,
KEYED or VOX). The cable should have 6 conductors, with the MIC and PHONE pairs shielded (MIC
wires must be shielded as a minimum). To ensure proper shielding, the shield(s) should be terminated to
the MIC LO connection at the airframe connector of the PTT drop cord. See the drawing below for
details.
To avoid complications in the aircraft, it is recommended that the same type of PTT drop cord is used for
all headset locations in the aircraft. It is not good practice to create a situation where a specific drop cord
is needed for the copilot, which might cause operational errors if moved to a passenger location.
ENG-FORM: 805-0116.DOT
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