PS Engineering PMA4000 Pilot’s Guide - Manual (Page 4)

4 PMA4000 TSO-Pilot Guide & User Manual
lected transceiver is automatically heard in the headsets and speaker (when
selected). You can check this function by switching from C
OM 1 to C OM 2
and watch the selected audio light on the selector change from C1 to C2.
This ensures the pilot will never transmit on a radio is not listening to.
When switching from C
OM 1 to C OM 2 while Com 2 has NOT been se-
lected, Com 1 audio will be switched off. In essence, switching the mic
selector will not effect the selection of Com receiver audio.
Volume Control
The pilot volume control knob adjusts the loudness of intercom and music
in the pilot’s headphones only. It has no effect on selected radio audio
levels. The copilot volume control adjusts the loudness of the intercom and
music in the copilot headset. The passenger volume is also adjusted by the
copilot volume control. Most general
aviation headsets have a built-in volume
control, so volume can be adjusted
“locally.” The copilot volume control is
also controllable through the rear
connector, so a tandem aircraft can adjust
the volume from a different location.
VOX-Squelch Control
The PMA4000 incorporates PS Engineer-
ing’s revolutionary IntelliVox® No adjust-
ment of the squelch control is required. Through two individual signal
processors, the ambient noise appearing in all four microphones is con-
stantly being sampled. Non-voice signals are blocked. When someone
speaks, only their microphone circuit opens, placing their voice on the in-
tercom.
The system is designed to block continuous tones, therefore people hum-
ming or whistling in monotone may be blocked after a few moments.
For best performance, the headset microphone must be placed within ¼
inch of your lips, preferably against them. It is also a good idea to keep the
microphone out of a direct wind path. Moving your head through a vent air
stream may cause the IntelliVox® to open momentarily. The IntelliVox® is
designed to work with normal aircraft cabin noise levels (70 dB and
above). It loves airplane noise! Therefore, it may not recognize speech and
clip syllables in a quiet cabin, such as in the hangar, or without the engine
running. This is normal.
For optimum microphone performance, PS Engineering, Inc. recommends
installation of a Microphone Muff Kit from Oregon Aero (1-800-888-
6910). This will not only optimize VOX performance, but will improve the
overall clarity of all your communications.