Audio Controller Interface; Backlighting; Unswitched Inputs - PS Engineering PAC45A Installation And Operation Instructions Manual

At minimum input voltage (20V):

Control head: 600mA

Hub Only: 950mA
Lighting input: <5mA
CAUTION: Do not connect or disconnect (
damage the units
2.4.2.1 Alert power, P451 Pin 41,
The PAC45A has an independent alert system with the ability to play alerts even when the audio controller
is powered off. To take full advantage of this isolation a separate one (1) Amp circuit breaker is required.
Power should be #22AWG connect power to P451 Pin 41.
When power to P451-42 is present, the message will play three times or until the remote acknowledge is
selected.
2.4.2.2 Failsafe Power P451 Pin 62 and O
When connected to the aircraft bus, it allows for the use of Oxygen microphones in failsafe, when the O
microphone discrete, J453 Pin 26 is grounded.
2.4.3

Audio controller interface

The PAC45A is designed to interface with standard aircraft avionics, and presents a 510  receiver imped-
ance. For best results, a twisted-shielded cable is recommended from the avionics audio source to the audio
controller, with the shield grounded at the audio controller end.
Some avionics do not provide a separate audio low, and may introduce additional electrical noise into the
system. For best results, connect the audio low from the audio controller to the radio ground, using one
conductor of the twisted-shielded cable.
2.4.3.1 Installation with Monaural Headsets
Not recommended, because the benefit of MultiTalker is lost.
However, if desired, the PAC45A can be installed monaurally by using the right and left
outputs together. However the HUB45AR DIP switches must be set for Mono configura-
tion. See §2.5.3.
2.4.4

Backlighting

Control of the unit backlighting is through the aircraft avionics dimmer, each control head is independent.
Connect J455 Pin 6 to the aircraft dimmer bus. The ratio of white to green indicator intensity is adjustable,
see §2.5.3. Backlight voltages of 5 VDC, 14 VDC and 28 VDC are configurable. See §2.5.2.
2.4.5

Unswitched inputs

These inputs are presented to the pilot and copilot regardless of the audio configuration, and will always mute
the crew entertainment inputs. These 510Ω inputs can be used for altimeter DH audio, TAWS audio, TCAS
audio or any other critical audio signal.
Unswitched #1 is always presented to the crew headphones, and is available to the pilot in fail-safe (off)
mode. Unswitched 2 is presented to the copilot in fail-safe.
Unswitched
Input
1
2
3
4
5
200-045-1000
) any components with power applied, this may
HOT SWAP
Enable P453 Pin 26
2
Input Pins Hear in
Fail Safe
P452 - 55 15 Pilot
WRT
P452 - 35 16 Copilot
WRT
P452 - 56 17 No
WRT
P452 - 36 18 No
WRT
P452 -57 19 No
WRT
Page 2-4
Hear in
Headset
Pilot
Copilot
Pilot & Copilot
Pilot & Copilot
Pilot & Copilot
Rev. 2, March 2019
2