Installation manual
PS Engineering 
PMA6000 Series Audio Selector Panel and Intercom System 
Installation Manual 
200-066-0100  Page 3-3  Rev. 1, March 2005 
3.6 Intercom  
3.6.1  Volume Control (6000, 6000M, 6000C, 6000MC) 
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 
only. The passenger volume is factory set at a comfortable level. 
This is a service adjustment that can be accessed by the avionics 
technician. Most general aviation headsets have a built-in 
volume control, so volume can be adjusted “locally.” 
3.6.2  Adjusting the VOX-Squelch control, (6000, 6000M, 6000MC) 
The PMA6000 provides adjustable VOX squelch controls for the pilot and copilot (the copilot's VOX con-
trol also adjusts the passengers VOX squelch). Since the number of microphones open at any one time is 
reduced, the amount of background noise is diminished. This also allows the use of dissimilar headsets 
with the same intercom. The user can adjust the trip level of the VOX to fit the individual's voice and mic, 
which helps eliminate the frustration of clipping the first syllables. 
With the engine running, set the VOX control knob by slowly rotating the S
QL control knob clockwise 
until you no longer hear the engine noise in the headphones. When the microphone is positioned properly 
near your lips, normal speech levels should open the channel. When you have stopped talking, there is a 
delay of about ½ second before the channel closes. This helps prevent choppy communications. 
3.6.3 Intercom Modes 
The center switch is a 3-position mode switch that allows the pilot to tailor the intercom function to best 
meet the situation. The description of the intercom mode function is valid only when the unit is either in 
the C
OM 1 or COM 2 position of the Mic Selector switch. When the unit is in the "Split" mode, only the 
passengers have intercom function. 
I
SO: (Up Position): The pilot is isolated from the intercom and is connected only to the aircraft radio. He 
will hear the aircraft radio reception (and sidetone during radio transmissions). Copilot and passengers will 
hear the intercom and music on Entertainment 1, but not the aircraft radio receptions or pilot transmissions. 
A
LL: (Middle Position): All parties will hear the aircraft radio, intercom, and music from entertainment 
input #1. However, during any intercom communications, the music volume automatically decreases when 
SoftMute is active (See section 3.6.5.1). The music volume increases gradually back to the original level 
after communications have been completed. 
C
REW (Down Position): Pilot and copilot are connected on one intercom channel and have exclusive ac-
cess to the aircraft radios. They may also listen to Entertainment 1. Passengers can continue to communi-
cate with themselves without interrupting the Crew and also may listen to Entertainment 2. Anytime the 
PMA6000 is in either the C
OM 1/COM 2, COM 2/COM 1, or TEL/COM 1, ("Split Mode") the pilot and copilot 
do not have any intercom function. The passengers will maintain intercommunications. 
3.6.3.1 Soft Mute 
Soft Mute must be enabled during installation by connecting top connector pins 12 and N. A SPST switch 
can be installed between these pins for a pilot selectable mute mode. Without this connection, music is not 
muted during intercom activation. This “Karaoke Mode” prevents the music muting when a sing-along is 
desired. "Soft Mute" mode only applies to entertainment input #1. Entertainment #2 does not mute. 
Figure 3-3 Volume Controls 










