PS Engineering PM501 Operator And Installation Manual page 5

for transmissions.
There are three configurations that can be
used. You select the case that best fits your instal-
lation requirements.
NOTE: Only the person who presses their
PTT switch will be heard over the radio.
CASE I
PTT built into the pilot and copilot
yokes
Simply install the plugs from the head-
set into the aircraft headphone jacks. Use
the yoke mounted PTT to transmit. No
other action is required.
CASE II
Built-in PTT on the pilot side only, but
copilot transmit capabilities desired.
This configuration requires a modified
external PTT plugged into the copilot's
mic jack. See Appendix A for modifica-
tion details. When the copilot's PTT is
depressed, this activates an intercom relay
that switches the mic audio input to air-
craft radio to the copilot.
CASE III
No built-in PTT switch at all
If there is no built-in PTT switch at all,
an external, properly modified PTT
switch is required. Both the pilot and co-
pilot may use an external PTT. (See Ap-
pendix A.)
OPERATING INSTRUCTIONS
With the installation complete, turn the
PM501 on pressing the volume control knob (left
knob). This also engages the automatic fail-safe
system.
Revision 7 Feb. 2008
Adjusting The Volume
The volume control knob adjusts the loud-
ness of the intercom and music for all headsets.
Turning the control clockwise increases the
audio. Many headsets have volume controls on
them. If it becomes necessary to reduce the vol-
ume for an individual passenger, the three oth-
ers should be set at maximum, and the unit vol-
ume set for a comfortable level. The individual
can then reduce their volume accordingly.
The radio volume is not affected for the by
the PM501 Volume Control. This gives added
flexibility for communications requirements.
Mode
Volume
Switch
Control
CW to
Increase
PM501 Front Panel Controls
Note: Unit volume is not affected by plugging
in other headsets.
Adjusting The Squelch Control
This VOX operated intercom keeps all mi-
crophone channels off while the pilot, copilot or
passengers are not speaking. This reduces back-
ground noise from the aircraft. Only when
someone speaks will their microphones auto-
matically turn on, passing the audio through the
system.
Set the Squelch control knob by slowly
Page 5
VOX Squelch
Control CW to
increase amount of
voice necessary to
open
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