Garmin G900X Pilot's Manual - page 123

190-00726-00  Rev. A

Garmin G900X Pilot’s Guide

4-1

AUDIO PANEL AND CNS

SECTION 4  AUDIO PANEL AND CNS

4.1  OVERVIEW

The Communication/Navigation/Surveillance (CNS) system includes the Audio Panel, communication radios, 

navigation radios, and Mode S transponder.  The System Overview Section provides a block diagram description 

of the Audio Panel and CNS system interconnection.

CNS operation in the G900X is performed by the following Line Replaceable Units (LRUs):

• GDU 1040 Primary Flight Display (PFD)

• GDU 1040 Multi Function Display (MFD)

• GIA 63W Integrated Avionics Units (2)

• GMA 1347 Audio Panel

• GTX 33 Mode S Transponder

• GCU 476 PFD/MFD Control Unit (optional)

The PFD/MFD controls are used to tune the communication transceivers and navigation radios.

The Audio Panel provides the traditional audio selector functions of microphone and receiver audio selection.  

The Audio Panel includes an intercom system (ICS) between the pilot, copilot, and passengers, a marker beacon 

receiver, and a COM clearance recorder.  Ambient noise from the aircraft radios is reduced by a feature called 

Master Avionics Squelch (MASQ).  When no audio is detected, MASQ processing further reduces the amount of 

background noise from the radios.

The Mode S Transponder is controlled with softkeys and the 

FMS

 Knob located on the Primary Flight Display 

(PFD).  The Transponder Data Box is located to the left of the System Time Box.  The data box displays the active 

four-digit code, mode, and reply status (Figure 4-1).