PS Engineering PAC45A Installation And Operation Instructions Manual

9800 Martel Road

Lenoir City, TN 37772

www.ps-engineering.com

PAC45A

Special Mission Audio Controller System

with MultiTalker™ and IntelliVox®

Document P/N 200-045-1000

Revision 2, March 2019

Audio Control System with Intercom

System Installation and Operation Manual

Patented under one or more of the following;

No. 4,941,187; 5,903,227; 6,160,496 and 6,493,450, 7,391,877

PS Engineering, Inc. 2019 ©

Copyright Notice
Any reproduction or retransmittal of this publication, or any portion thereof, without the expressed written permission of PS En­gineering, Inc. is strictly prohibited. For further information, contact the Publications Manager at PS Engineering, Inc., 9800
Martel Road, Lenoir City, TN 37772. Phone [phone], email [e-mail].

In certified aircraft, warranty is not valid unless this product is installed by an

Authorized PS Engineering dealer.

Table of Contents

Section I – GENERAL INFORMATION ................................................................ 1-1

1.1 INTRODUCTION ............................................................................................................................................. 1-1

1.1.1 LIMITATIONS..................................................................................................................... 1-1

1.2 SCOPE ................................................................................................................................................................ 1-1

1.3 EQUIPMENT DESCRIPTION ........................................................................................................................ 1-1

1.4 APPROVAL BASIS FAA TSO (PENDING) ....................................................................................................... 1-2

1.1.2 LIMITATIONS..................................................................................................................... 1-2

1.5 SPECIFICATIONS ........................................................................................................................................... 1-2

1.6 EQUIPMENT SUPPLIED ................................................................................................................................ 1-3

1.8 CONFIGURATION ................................................................................................................................................. 1-5

1.9 LICENSE REQUIREMENTS .......................................................................................................................... 1-5

Section II - INSTALLATION ................................................................. 2-1

2.1 GENERAL INFORMATION ........................................................................................................................... 2-1

2.1.1 SCOPE .............................................................................................................................. 2-1

2.1.2 CERTIFICATION REQUIREMENTS ...................................................................................... 2-1

2.2 UNPACKING AND PRELIMINARY INSPECTION ...................................................................................................... 2-1

2.3 EQUIPMENT INSTALLATION PROCEDURES .......................................................................................................... 2-1

2.3.1 COOLING REQUIREMENTS ................................................................................................ 2-1

2.3.2 MOUNTING REQUIREMENTS ............................................................................................. 2-1

2.3.3 AUDIO CONTROLLER CONNECTOR ASSEMBLY ................................................................. 2-2

2.4 CABLE HARNESS WIRING .................................................................................................................................... 2-3

2.4.1 ELECTRICAL NOISE ........................................................................................................... 2-3

2.4.2 POWER .............................................................................................................................. 2-3

2.4.3 AUDIO CONTROLLER INTERFACE ...................................................................................... 2-4

2.4.4 BACKLIGHTING ................................................................................................................. 2-4

2.4.5 UNSWITCHED INPUTS ........................................................................................................ 2-4

2.4.6 COCKPIT VOICE RECORDER.............................................................................................. 2-5

2.4.7 AUDIO ALERTS ................................................................................................................. 2-5

2.5 DUSCRETE INPUTS ............................................................................................................................................... 2-5

2.5.1 REMOTE ICS MODE CONTROL. ......................................................................................... 2-5

2.5.1 OXY (P453-26) ................................................................................................................ 2-6

2.5.2 RECEIVE MUTE (J452-44) ................................................................................................. 2-6

2.6 WIRED TELEPHONE/SATELLITE COMMUNICATION INPUT .................................................................................. 2-6

2.7 USER ADJUSTMENTS ............................................................................................................................................ 2-7

2.7.1 UNSWITCHED AUDIO LEVEL ............................................................................................ 2-7

2.7.2 ADJUSTMENTS .................................................................................................................. 2-7

2.7.3 LOGIC SWITCH OPTIONS ................................................................................................... 2-9

2.8 PAC45A PIN ASSIGNMENTS .............................................................................................................................. 2-10

2.9 WIRING CHECKOUT .......................................................................................................................................... 2-11

2.10 OPERATIONAL CHECKOUT ................................................................................................................................ 2-12

2.10.1 REQUIRED TEST EQUIPMENT ........................................................................................ 2-12

2.10.2 AUDIO CONTROLLER TEST............................................................................................ 2-12

2.10.3 BLUETOOTH CHECKOUT ............................................................................................... 2-13

2.11 FINAL INSPECTION ............................................................................................................................................ 2-13

Section III OPERATION ................................................................. 3-1

3.1 SCOPE ................................................................................................................................................................ 3-1

3.2 POWER AND FAIL SAFE ....................................................................................................................................... 3-1

3.3 COMMUNICATIONS TRANSMIT (XMT) SELECTION ............................................................................................ 3-1

3.4 COM AUDIO SELECTOR ..................................................................................................................................... 3-1

3.5 NAVAID SELECTION ............................................................................................................................................. 3-2

3.5.1 OXY (P453-26) ................................................................................................................ 3-2

3.5.2 RECEIVE MUTE (J452-44) ................................................................................................. 3-2

3.6 INTERCOM OPERATION (8) .................................................................................................................................. 3-2

3.6.1 INTELLIVOX® INTERCOM VOX-SQUELCH ........................................................................ 3-2

3.6.2 INTERCOM VOLUME CONTROL ......................................................................................... 3-3

PS Engineering

PAC45A Audio Selector Panel and Intercom System

Installation and Operator’s Manual

200-045-1000 Page ii Rev. 2, March 2019

3.6.3 INTERCOM MODES ............................................................................................................ 3-3

3.7 SPEAKER OPERATION .......................................................................................................................................... 3-4

3.8 ALERT AUDIO ...................................................................................................................................................... 3-4

Section IV – Warranty and Service ................................................................. 4-1

4.1 WARRANTY ......................................................................................................................................................... 4-1

4.2 FACTORY SERVICE .............................................................................................................................................. 4-1

Appendix A – PAC45A Installation Drawings ........................................................... A

Appendix B – Radio Interconnect Wiring .................................................................. B

Appendix C – Intercom Interconnect Wiring ............................................................ C

Appendix D – Control Head Interconnect Wiring .................................................... D

Appendix E – Unit Connector Wiring Reference ...................................................... E

9.1 J451 CONNECTIONS ................................................................................................................................................ E

9.2 J452 CONNECTIONS ................................................................................................................................................ E

9.3 J453 CONNECTIONS ................................................................................................................................................ E

9.4 J454 CONNECTIONS ................................................................................................................................................ E

9.5 J455 CONNECTIONS ................................................................................................................................................ E

Appendix F – Instructions for FAA Form 337 and continuing airworthiness ........ F

10.1 INSTRUCTIONS FOR FAA FORM 337, AUDIO CONTROLLERS .................................................................................. F

10.2 INSTRUCTIONS FOR CONTINUING AIRWORTHINESS, AUDIO SYSTEM ..................................................................... F

Appendix G – RTCA DO160G Environmental Qualification Form ...................... G

11.1 MODEL NUMBER PAC45A AUDIO SELECTOR PANEL/INTERCOM REMOTE HUB ................................................ G

11.2 MODEL NUMBER CTL45, AUDIO SELECTOR CONTROL PANEL ........................................................................... G

Rev

Date

Change

New

Jan. 2019

Initial Draft Manual

1

January 2019

After Internal Review

2

March 2019

Release for publication

200-045-1000 Page 1-1 Rev. 2, March 2019

Section I – GENERAL INFORMATION

1.1 INTRODUCTION

The PAC45A represents a revolutionary step in cockpit audio control and intercommunications utility.
MultiTalker™, using licensed U.S. Air Force patented technology, provides True Dimensional Sound,
helping pilots to more easily discern from simultaneous radio receptions..

1.1.1 Limitations

This article meets the minimum performance and quality control standards required by a technical standard
order (TSO). Installation of this article requires separate approval. Refer to Advisory Circular 20-41A for
information on TSO installation approval.

Operation is subject to the following conditions:

 This device may not cause harmful interference.
 This device must accept any interference received, including interference that may cause undesired

operation.

1.2 SCOPE

This manual provides installation and operation instructions for the PS Engineering PAC45A-series of Audio
Selector Panel/Intercom Systems. This includes the following units:

Model Number

Description

PS Engineering

Part Number

HUB45R

Remote-mounted Audio Hub for analog I/O and processing

050-045-1001

CTL45A

Panel Mounted Control Head for Flight Crew

050-045-2000

GTL45A-M

Panel Mounted Control Head for Mission Observers

050-045-3000

CTL45A-NVG

Panel Mounted Control Head for Flight Crew, Night Vision
Compatible

050-045-4000

GTL45A-M

NVG Panel Mounted Control Head for Mission Observers,
Night Vision Compatible

050-045-5000

1.3 EQUIPMENT DESCRIPTION

The PAC45A is a state-of-the-art audio isolation amplifier and audio selector that contains an automatic voice
activated (VOX) intercom system. It can switch up to eight transceivers (COM 1 to 8) and eight navigation
receivers (AUX 1 to 8) that can be configured as desired.

There are up to five unswitched inputs, available for traffic or EGPWS, autopilot disconnect, and/or radar
altimeter warning.

In addition, nine programmable alerts can be triggered by external sources to provide additional capability.
In addition to a radio master volume, the individual volume controls select the receiver audio source provided

to the headphones when selected to the “out” position.
A nine-station voice activated (VOX) intercom is included in the PAC45A. This system has PS Engineering’s

patented IntelliVox® circuitry that eliminates manual adjustments.

200-045-1000 Page 1-2 Rev. 2, March 2019

1.4 APPROVAL BASIS FAA TSO (Pending)

1.1.2 Limitations

This article meets the minimum performance and quality control standards required by a technical standard
order (TSO). Installation of this article requires separate approval.
Refer to Advisory Circular 20-41A for information on TSO installation approval.
Operation is subject to the following conditions:
This device may not cause harmful interference.
This device must accept any interference received, including interference that may cause undesired operation.

1.5 SPECIFICATIONS

TSO COMPLIANCE

Audio Selector/Intercom:

FAA TSO-C139A

APPLICABLE DOCUMENTS:

RTCA/DO-214A
RTCA/DO-160G
RTCA/DO-178C

Temperature Range:

Operating:
Short Term Operating:
Survival:

-20º C to +55ºC

-20°C to +70°C

-55º C to +85ºC Cold soak to –40˚C

Altitude:

Up to 55,000 feet in a non-pressurized area of the cockpit.

DIMENSIONS:

CTL45A: Height: 1.88 in. (4.78cm) Width: 4.90 in. (12.45 cm)
Depth behind panel: 2.35 in. (5.97)
HUB45R: Height: 1.9” Width: 5.88 w/mounting flanges, Length

7.22”, 12” w/ all connectors. See Figure 5-6

UNIT WEIGHT
HUB45R
CTL45A

2.0 lbs. (.91 kg)

1.0. (.45 kg)

POWER REQUIREMENTS :

Voltage:

18 to 33 VDC

Maximum Current:

Typical Current
Alert Power
Lighting

HUB45R 1.5 Amp (Externally protected by a 5 Amp circuit breaker.)
CTL45 500 mA (Externally protected by a 1 Amp circuit breaker)
750 mA
<20 mA
< 5mA

Audio Selector Specifications

Audio selector panel input impedance:

510 

Input Isolation:

-60 dB (min.)

Switched Receiver Inputs:

16 (COM 1– COM 8, AUX 1- 8)

Unswitched Inputs:

5

Transmitter Selections:

8 (COM 1, 2, 3, 4, 5, 6, 7, 8)

Headphone Impedance:

150 – 600  or 8 Ω

Headphone Output:

200 mW into 150 or 8Ω headset, no clipping <.5% THD
typical

Microphone Impedance:

150 - 600 

PA Output, Cockpit speaker output

10W @4 Ω

Intercom Specifications

Intercom Positions:

Up to 9 places (with individual IntelliVox® circuits)

Distortion:

<1% THD @ 200 mW into 150

Mic Freq. Response, ±3 dB:

300 Hz - 6000 Hz

200-045-1000 Page 1-3 Rev. 2, March 2019

1.6 EQUIPMENT SUPPLIED

The following units comprise the PAC45A System:

Model

Description

Part Number

HUB45AR

Remote-mounted Audio Hub for analog I/O and processing

050-045-1001

CTL45A

Control Head for pilot or copilot positions

050-045-2000

CTL45A-M

Panel-mounted Control Head for Observers

050-045-3000

CTL45A-NVG

NVG Panel-mounted Control Head for pilot and copilot po-

sitions

050-045-4000

CTL45M-NVG

NVG Panel-mounted Control Head for Observers

050-045-5000

PAC45A Installation Kit: 250-045-0801

Male Connector Kit 250-045-8177 (P452, P454)

Part Number

Description

MFR

MFR PN

Quantity

625-015-9215

Connector Backshell DB26 pin

3M

3357-9215

1

625-037-9237

Connector Backshell DB62 pin

3M

3357-9237

1

425-026-5601

Male Connector Shell DB26 pin

Harting

9562005601

1

425-062-8177

Male Connector Shell DB62 pin

Harting

9564005601

1

425-044-2043

Hi-density Male Pins

AMP

204370-2

88

475-045-3341

Thumbscrew Kit for DB Connector

3M

3341-7

4

Female Connector Kit 250-045-8277 J451, J453)

Part Number

Description

MFR

MFR PN

Quantity

625-015-9215

Connector Backshell DB26 pin

3M

3357-9215

1

625-037-9237

Connector Backshell DB62 pin

3M

3357-9237

1

425-026-1800

Female Connector Shell DB26 pin

Norcomp

180-026-273L000

1

425-062-4701

Female Connector Shell DB62 pin

Harting

99564004701

1

425-030-7354

Hi-density Female Pins

Amphenol

M39029/57-354

88

475-045-3341

Thumbscrew Kit for DB Connector

3M

3341-7

4

9-Pin Connector Kit 250-045-0009 ( P455)

Part Number

Description

MFR

MFR PN

Quantity

625-009-1724

Connector Backshell DB9 pin

3M

3357-9209

1

425-009-0777

Male Connector Shell DB9 pin

Amphenol

L777-RR-E-09-P

9

425-020-5089

Standard Density Male Pins

Deutsch

M39029/64-369

9

475-045-3341

Thumbscrew Kit for DB Connector

3M

3341-7

2

CTL45 9-Pin Female Connector Kit 250-543-0100 ( J455)

Part Number

Description

MFR

MFR PN

Quantity

200-045-1000 Page 1-4 Rev. 2, March 2019

625-009-9209

Connector Backshell DB9

3M

3357-9209

1

425-009-7709

Connector Female Shell DB9

Amphenol

L177-RR-E-09-S

1

425-020-5090

Standard density female pins

Deutsch

M39029/63-368

9

475-045-3341

Thumbscrew Kit for DB Connector

3M

3341-7

2

External Bluetooth Antenna

Part Number

Description

MFR

MFR PN

Quantity

300-045-1351

Bluetooth Coaxial Cable SMA ST BH JK to
ST Plug RG 174/U 36

Amphenol

135110-02-36”

1
510-045-9602

Bluetooth Antenna

Taoglas

GW.26.0112.HT

1

EQUIPMENT REQUIRED BUT NOT SUPPLIED

a. Circuit Breakers: 1 ea.; 5 amp PULL TYPE REQUIRED for HUB45G, 1 A for CTL45As
b. Optional Circuit Breakers: 1 ea.; 1 amp PULL TYPE REQUIRED for PAC45A aural alerts, 1 ea. 1 A for

failsafe power

c. Headphone Jacks (as Required)
d. Microphone Jacks (as Required)
e. Headphones, as required
f. Microphones, as required
g. Interconnect Wiring

200-045-1000 Page 1-5 Rev. 2, March 2019

1.8 Configuration

The PAC45A System is comprised of a single PAC45A HUB (HUB45R) and up to four CTL45 Control
Head “building blocks” to facilitate flexibility as well as simplicity.

HUB45AR

Pilot Copilot

Passenger 1

RS422 RS422 RS422RS422

Hand

Observer 1Crew 3 Observer 2

Passenger 2

Passenger 3 Passenger 4

CVR CP

PA

COM1-8

NAV 1-2

Aux 3-8

UNSW1-5

Telephone

Music

Bluetooth

Telephone

Bluetooth

Music

CVR P

Pilot

CopilotAmp

Figure 1-1 Baseline configuration

1.9 LICENSE REQUIREMENTS

None

200-045-1000 Page 2-1 Rev. 2, March 2019

Section II - INSTALLATION

2.1 GENERAL INFORMATION

2.1.1 SCOPE

This section provides detailed installation and interconnection instructions for the PS Engineering PAC45A
Audio Selector Panel/Intercom.

Please read this manual carefully before beginning any installation to prevent damage and post-installation
problems.

Installation of this equipment requires special tools, test equipment (refer to §2.12.1) and installer knowledge
as required by 14 CFR 65.81 (b).

2.1.2 Certification Requirements

NOTE

The PAC45A requires specialized knowledge and tools for an effective installation. An appropriately rated
Certified Aircraft Repair Station must install this equipment in accordance with applicable regulations. PS
Engineering, Incorporated warranty is not valid unless the equipment is installed by an authorized PS Engi­neering, Incorporated dealer.
Failure to follow any of the installation instructions, or installation by a non-certified individual or agency
will void the warranty, and may result in an unairworthy installation.

This article meets the minimum performance and quality control standards required by a technical standard
order (TSO). Installation of this article requires separate approval. Refer to AC 20-41A for information
regarding Substitute TSO Aircraft Equipment.

2.2 Unpacking and Preliminary Inspection

Use care when unpacking the equipment. Inspect the units and parts supplied for visible signs of shipping
damage. Examine the unit for loose or broken buttons, bent knobs, etc. Verify the correct quantity of com­ponents supplied with the list in §1.6. If any claim is to be made, save the shipping material and contact the
freight carrier. Do NOT return units damaged in shipping to PS Engineering. If the unit or accessories show
any sign of external shipping damage, contact PS Engineering to arrange for a replacement. Under no cir­cumstances attempt to install a damaged unit in an aircraft. Equipment returned to PS Engineering for any
other reason should be shipped in the original PS Engineering packaging, or other UPS approved packaging.

2.3 Equipment Installation Procedures

2.3.1 Cooling Requirements

Forced air-cooling of the PAC45A is not required. However, the units should be kept away from heat pro­ducing sources (i.e. defrost or heater ducts, dropping resistors, heat producing avionics) without adequate
cooling air provided.

2.3.2 Mounting Requirements

The HUB45R must be rigidly mounted to the aircraft structure in an avionics-rated location. The CTL45 is
designed for Dzus-rail mounting within view and reach of the flightcrew position(s). Installation must comply
with FAA Advisory Circular AC 43.13-2B, or other FAA-approved aircraft technical data. The unit may be
mounted in any area where adequate clearance for the unit and associated wiring bundle exist.

To prevent noise, avoid installing the unit close to high current devices or systems with high-voltage pulse
type outputs, such as DME or transponders. Avoid running the interconnecting bundles near any high current
wires.

200-045-1000 Page 2-2 Rev. 2, March 2019

2.3.3 Audio controller connector assembly

The HUB45R LRU connectors mate with two 62-pin, and two 26-pin connectors. One of each gender. The
connectors are a sub-miniature crimp-type, and require the use a hand crimp tool, from table below (or
equiv.).

P451

P453

J454J452

121

22

43

62

42

1

21

22

43

62

42

1 9

19 26

10 18

19

26

10

18

19

Figure 2-1 - PAC45A Connector Layout

Figure 2-2 - Connector assembly
NOTE: Pass the wire bundle through the Cover Nut before inserting pins in the connector shell.

Insert the screw or thumbscrews through the top half of the shell (B), and apply the E-Ring to the unthreaded
portion, and bend the E-ring holder back and forth to break it from the holder. Repeat for the other side.

Place the harness and connector in the bottom portion (A), and fold the retaining pars over the wires. Install
the top shell (B) by inserting the screws the screws through the connector, and snapping the top over the
bottom until the lances are in the cutouts. Be sure to align the lip of the shell over the connector edge before
snapping in place. Slide the cover nut over the two haves and screw in place.

Ensure that proper strain relief and chafing precautions are made during wiring and installation.

200-045-1000 Page 2-3 Rev. 2, March 2019

Manufacturer

Crimping Tool

Positioner

Extraction tool

AMP

601966-1

601966-6

91067-1

Daniels

AFM8

K42

M24308-1

ITT-Cannon

995-0001-584

995-0001-739

91067-1

Table 2-1 Connector Pin crimping tools

2.4 Cable Harness Wiring

Referring to the appropriate Appendix, assemble a wiring harness as required for the installation. All wires
must be MIL-SPEC in accordance with current regulations. Two- and three-conductor shielded wire must be
used where indicated, and be MIL-C-27500 or equivalent specification. Proper stripping, shielding and sol­dering technique must be used at all times. It is imperative that correct wire be used.

Refer to FAA Advisory Circular 43.13-2B for more information. Failure to use correct techniques may result
in improper operation, electrical noise or unit failure. Damage caused by improper installation will void the
PS Engineering warranty.

See Appendix C and D for intercom connection configurations. It is critical to the proper operation of this
system to have this connector wiring made in accordance with these diagrams. Use 2- and 3-conductor, MIL­spec cable as shown. Connect the shields at the audio controller end only, and tie to the audio low inputs as
shown.

2.4.1 Electrical Noise

Due to the variety and the high power of radio equipment often found in today's aircraft, there is a potential
for both radiated and conducted noise interference.

The PAC45A power supply is specifically designed to reduce conducted electrical noise on the aircraft power
bus by at least 50dB. Although this is a large amount of attenuation, it may not eliminate all noise, particularly
if the amplitude of noise is very high. Shielding can reduce or prevent radiated noise (i.e., beacon, electric
gyros, switching power supplies, etc.) However, installation combinations can occur where interference is
possible. The PAC45A was designed in a RFI hardened chassis and has internal Electromagnetic Interference
(EMI) filters on all inputs and outputs.

Ground loop noise occurs when there are two or more ground paths for the same signal (i.e., airframe and
ground return wire). Large cyclic loads such as strobes, inverters, etc., can inject noise signals onto the air­frame that are detected by the audio system. Follow the wiring diagram very carefully to help ensure a min­imum of ground loop potential. Use only Mil Spec shielded wires (MIL-C-275000, or better). Under no
circumstances, combine a microphone and headphone wiring into the same shielded bundle. Always use a 2­or 3-conductor, shield wire as shown on the installation-wiring diagram.

The shields can be daisy-chained together, and then connected to the ground.
Radiated signals can be a factor when low-level microphone signals are "bundled" with current carrying

power wires. Keep these cables physically separated. It is very important that you use insulated washers to
isolate the ground return path from the airframe to all headphone and microphone jacks.

2.4.2 Power

The PAC45A is compatible with 28 Volt DC systems. A five (5) Amp circuit breaker is required for all
installations. Power and ground wires should be #22AWG connect power to P451 Pin 42. Connect airframe
ground to P451 Pin 20 and 21 only.

Power consumption is as follows:
At 28V:

 Control head Only: 400 mA
 Hub Only: 750 mA
 Alert audio power: 20mA

200-045-1000 Page 2-4 Rev. 2, March 2019

At minimum input voltage (20V):

 Control head: 600mA
 Hub Only: 950mA

Lighting input: <5mA

CAUTION: Do not connect or disconnect (HOT SWAP) any components with power applied, this may
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 O2 Enable P453 Pin 26

When connected to the aircraft bus, it allows for the use of Oxygen microphones in failsafe, when the O2
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 imped­ance. 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

Input Pins

Hear in

Fail Safe

Hear in

Headset

1

P452 - 55 WRT 15

Pilot

Pilot

2

P452 - 35 WRT 16

Copilot

Copilot

3

P452 - 56 WRT 17

No

Pilot & Copilot

4

P452 - 36 WRT 18

No

Pilot & Copilot

5

P452 -57 WRT 19

No

Pilot & Copilot