Revision 8, May 2020
Page 5
200-123-0003
5.Verify that the pilot can transmit and receive on
the com transceivers.
6.Verify that the LED in the intercom changes
from green to red when a microphone is
keyed.
7.Verify proper intercom operation for pilot, copi-
lot and passengers. For more information,
consult Section III.
8.Verify proper transmit and receive operation on
the copilot position, noting that the copilot
PTT switch allows proper transmission on the
selected transceiver.
9.Verify proper Intercom system operation in the
ALL, ISO And CREW (if equipped) modes.
10.Verify that the intercom system does not ad-
versely affect any other aircraft system by
systematically switching the unit on and off,
while monitoring the other avionics and elec-
trical equipment on the aircraft.
Section III OPERATION
With the installation complete, turn the
PM1000
II
on
by rotating pilot's volume control. This also engages
the automatic fail-safe system. The pilot's volume con-
trol does not control the volume of the aircraft radio,
allowing an additional degree of aircraft radio listening
flexibility.
3.1
Adjusting The Volume (1)
The pilot's volume control knob adjusts the loudness
of the intercom and music for the pilot's headset only.
It has no effect on aircraft radio volume level. The
copilot's volume control adjusts the volume for the
copilot.
In the 11920 units, the volume level for both passen-
gers can be adjusted by a screwdriver adjusted potenti-
ometer located on the left hand side of the intercom as
viewed from the front. It is possible to adjust the over-
all output power to the passenger headsets by changing
this potentiometer. Rotating the potentiometer counter-
clockwise increases the passenger volume.
3.2
Squelch Control (2)
The
PM1000
II
provides individual VOX circuits for
the pilot and copilot. The ability to adjust the trip level
of these VOX circuits (squelch control) allows the use
of dissimilar headsets without the frustration of clip-
ping the first syllables. The
PM1000
II
has three
squelch circuits, one for the pilot, copilot, and one for
the passengers. With individual VOX circuits, back-
ground noise is dramatically reduced.
With the engine running, set the squelch control knob
by slowly rotating the squelch control knob clockwise
until you no longer hear the background noise in the
earphones. When the microphone is positioned
properly near the lips, normal speech levels should
open the channel. When you have stopped talking,
there is a delay of about one second before the channel
closes. This prevents squelch closure between words,
and helps eliminates choppy intercom conversations.
3.3
Mode Select (3)
The center switch is a three position mode control that
allows the pilot to tailor the intercom function to suit
flight conditions. Regardless of configuration, the
pilot will always hear the aircraft radio. NOTE: If
there is a power failure to the
PM1000
II
, or if the
power switch is turned off, the copilot will not hear the
aircraft radio. Only the pilot is connected directly to
the aircraft radio.
ISO
(Up Position): The pilot is isolated from the inter-
com and is connected only to the aircraft radios. He
will hear the aircraft radio reception (and sidetone dur-
ing radio transmissions). The pilot will not hear any-
thing when he speaks into the mic on intercom. Copi-
lot and passengers will hear themselves and music but
not the aircraft radio traffic.
ALL
(Middle position): All parties will hear the air-
craft radio, intercom, and music. However, during any
ICS or radio communications, the music volume auto-
matically mutes. The music volume increases gradual-
ly back to the original level after communications have
been completed.
CREW
(Down Position) (ONLY version with crew,
part number 11920 ): Pilot and copilot are connected
on one intercom channel while the passengers are on a
separate and independent channel. The pilot and copi-
lot are connected to the aircraft radio and may listen to
Music #1. Passengers can continue to communicate
with themselves without disturbing the pilot and copi-
lot and may listen to Music #2.
PM1000
II
w/crew, p/n 11920
PM1000
II
w/out crew, p/n 11922