PS Engineering
PMA450B Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-450-0600
Page 3-7
Rev. 5, August 2020
The description of the intercom mode function is valid only when the unit is not in the "Split" mode. Then,
the pilot and copilot intercom are controlled by the ICS button selecting CRW.
I
SO
:
The pilot is isolated from the intercom and is connected only to the aircraft radio system. He will hear
the aircraft radio reception (and sidetone during radio transmissions). Copilot will hear passengers’ intercom
and Music, while passengers will hear copilot intercom and Music. Neither will hear aircraft radio receptions
or pilot transmissions. The pilot can hear music if desired. See §
A
LL
:
All parties will hear the aircraft radio and intercom. Crew and passengers will hear selected Music.
During any radio or intercom communications, the music volume automatically decreases. The music volume
increases gradually back to the original level after communications have been completed.
C
REW
: Pilot and copilot are connected on one intercom channel and have exclusive access to the aircraft
radios. They may also listen to Music 1. Passengers can continue to communicate with themselves without
interrupting the Crew and may listen to Music as configured.
3.8.3.1
Remote ICS Mode Control
The panel- or yoke-mounted optional “swap” switch can also act as a remote intercom mode selector in units
with serial and above. A long (>1 second) press of the swap switch will increment the intercom mode selector
from ISO-ALL-CRW-ISO, etc. each time the button is pressed and held. A short press activates the COM 1
to COM 2 to COM 1 swap function.
3.8.3.2
Alternate Intercom Mode
The PMA450B includes an Alternate Intercom Mode. This mode allows intercom communications between
crew and passengers, without interrupting the crews radio communications. The passengers do not hear the
aircraft radio audio. The passenger microphones are muted, such that the crew cannot hear the passengers’
microphone audio while the radio is active. Passengers can still talk to each other.
To enable the Alternate Intercom Mode, press
RADIO-ICS
: to switch between Standard, Alternate and Co-
pilot as Passenger modes. This state is remembered during power cycles.
Alternate Intercom Mode enabled
3.8.3.3
Copilot as Passenger (CP PAX) Intercom Modes
This function is useful when the right seat occupant does not wish to interact with the aircraft operation.
