TMA44 Audio Panel Installation Manual 7 November 2017
01849-00 Issue AB
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Page 2 Trig Avionics Limited
2. Introduction
2.1 Equipment Description
The TMA44 is a state of the art audio isolation amplifier and audio selector
that contains a voice activated (VOX) intercom system. It can switch up two
transceivers (Com 1, Com 2) and six receivers (Nav 1, Nav 2, ADF, DME,
MKR and AUX). In addition, there are two unswitched inputs, for priority
audio sources such as TAWS or altimeter warning. Push buttons select the
receiver audio sources provided to the headphones. A speaker button allows
the user to listen to the receiver(s) selected on the cabin speaker. Except for
the unswitched inputs, all speaker audio is muted during transmit. Push
buttons select one of the transceivers for the pilot and co-pilot position in
transmit. In "Split Mode" the TMA44 allows the pilot and co-pilot to operate
different transmitters independently.
A fail-safe mode connects the pilot headphone and microphone to Com 1 and
unswitched input 1 if power is removed for any reason, or if the audio panel is
turned off by pushing the volume control.
A four-station voice activated (VOX) intercom is included in the TMA44.
Pilot isolate and crew modes, two mono music inputs with "Soft Mute" and
transmit indications. Intercom control is through front panel mounted knobs.
Dual concentric knobs control intercom volume and intercom squelch.
A 3-light Marker Beacon receiver is integral to the TMA44. This provides the
necessary Marker Beacon light and audio indications necessary for an
Instrument Landing System (ILS) approach.
2.2 TSO Holder
The TSO holder and manufacturer of the TMA44 is PS Engineering, Lenoir
City, TN, USA.
US patents no. 5,903,227 and 6,160,496 apply.
SoftMute is a trademark of PS Engineering.
