PS Engineering
PAC45J Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-045-2000
Page 2-14
November 2020
2.7.5
Fail-Safe Audio and Reversionary Mode
2.7.5.1
Fail-Safe options
When
ON
, Switch 1 allows the crew to have Audio Alerts in Fail-Safe, when the alert subsystem is powered.
When Switch 2 is
ON
, the Observer positions will hear the audio alerts in Fail-Safe, when the alert subsystem
is powered.
Switches 3 and 4 provide the option for the pilot and copilot (Switch 3), and or observer positions (Switch 4)
to hear the Audio Alerts in normal operation.
2.7.5.2
Reversionary Mode
When Switch 28 is
ON
, CTL45J Control heads will “revert” to the next higher control head if it is turned off.
For example, of the Observer #2 control head is off, Observer 2 will hear what Observer 1 has selected and
transmit on the radios Observer 1 has selected. Or, if the copilot’s control head is switched off (fail-safe), the
copilot will hear what the pilot has selected and transmit on the radios the pilot has selected.
If Switch 28 is
OFF
, the user just goes into fail-safe, with no ability to change radios and hears the audio
associated with that position.
2.7.6
Microphone settings
2.7.6.1
Transmit Muting
Switch 29 controls the muting of other receivers when one is transmitting. When Switch 29 is
ON
, other
receivers are muted during transmission. This can prevent bleed over and squealing if they are operating on
close frequencies, or the antennas are close together. However, it prevents other crew members from hearing
radios they have selected for receiving during transmissions.
Sidetone from the transmitter is still heard when selected.
2.7.6.2
Stuck Mic P-T-T Enable
When Switch 30 is
ON
the PAC45J will ignore any push-to-talk input that is held low for more than 35
seconds. This function resets if the PTT ground is released. If Switch 30 is
OFF
, a PTT will key the selected
radio indefinitely, and rely on the radio’s internal stuck mic protection.
2.7.6.3
Microphone VOX Trip-level Sensitivity
If Switch 31 is
ON
, the intercom microphone sensitivity is decreased by 6dB. This makes the intercom more
resistant to noisy aircraft environments. PS Engineering recommends trying the PAC45J in normal mode
(Switch 31
OFF
) first, because the IntelliVOX® does perform very well in most airplanes and rotorcraft.
2.7.6.4
Oxygen Microphones or Passenger Intercom inputs
P453-15 and P453-16 can be either Passenger 1 and Passenger 2 intercom microphone inputs, or, when
Switch
32
is
ON
they will become Pilot and Copilot Oxygen microphone inputs. These are activated when
an OXY mode is on.
P453-17 and P453-18 can be either Passenger 3 and Passenger 4 intercom microphone inputs, or, when
Switch
33
is
ON
they will become Observer 1and Observer 2 Oxygen microphone inputs. These are activated
when an OXY mode is on.