PS Engineering PMA8000 User manual

9800 Martel Road
Lenoir City, TN 37772
www.ps-engineering.com
P
PM MA A8 80 00 00 0
Document P/N 200-890-0000
Revision 9, June 2005
Audio Selector Panel with Marker Beacon Receiver
High-fidelity Stereo Intercom
System Installation and Operation Manual
FAA-Approved TSO C50c, C35d
Patented under one or more of the following;
No. 5,903,277; 6,160,496 and 6,493,450
PS Engineering, Inc. 2005 ©
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 [email protected].
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
1.2 SCOPE............................................................................................................................................ 1-1
1.3 EQUIPMENT DESCRIPTION.................................................................................................... 1-1
1.4 APPROVAL BASIS – ................................................................................................................... 1-2
1.5 SPECIFICATIONS ....................................................................................................................... 1-2
1.6 EQUIPMENT SUPPLIED............................................................................................................ 1-4
1.7 EQUIPMENT REQUIRED BUT NOT SUPPLIED................................................................... 1-4
1.8 LICENSE REQUIREMENTS...................................................................................................... 1-4
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 PANEL MOUNTING RACK INSTALLATION .......................................................... 2-1
2.3.4 AUDIO PANEL TRAY AND CONNECTOR ASSEMBLY....................................................... 2-2
2.4 CABLE HARNESS WIRING............................................................................................................... 2-2
2.4.1 NOISE ............................................................................................................................. 2-2
2.4.2 EXISTING GMA340 INSTALLATION ............................................................................... 2-3
2.4.3 POWER............................................................................................................................ 2-3
2.4.4 COMMUNICATIONS PUSH-TO-TALK ............................................................................... 2-3
2.4.5 AUDIO PANEL INTERFACE .............................................................................................. 2-3
2.4.6 TEL (DUPLEX) FUNCTION FOR CELL PHONES............................................................... 2-3
2.4.7 TRANSMIT INTERLOCK................................................................................................... 2-4
2.4.8 PATENTED "SWAP" MODE ............................................................................................. 2-4
2.4.9 BACKLIGHTING .............................................................................................................. 2-4
2.4.10 UNSWITCHED INPUTS ................................................................................................... 2-4
2.4.11 PUBLIC ADDRESS MODE .............................................................................................. 2-5
2.4.12 PA MUTE (J2, PIN 12) .................................................................................................. 2-5
2.4.13 MISCELLANEOUS LOGIC OUTPUT (J2, PIN 18)............................................................. 2-5
2.4.14 INTERCOM WIRING ....................................................................................................... 2-5
2.4.15 PLAYBACK BUTTON INSTALLATION (J2, PIN 22- OPTION 1, ONLY)........................... 2-7
2.5 MARKER BEACON INSTALLATION.................................................................................................. 2-7
2.5.1 MARKER ANTENNA INSTALLATION ............................................................................... 2-7
2.5.2 EXTERNAL MARKER LIGHTS.......................................................................................... 2-7
2.5.3 MIDDLE MARKER SENSE (MARKER VERSION)............................................................... 2-7
2.6 ADJUSTMENTS................................................................................................................................. 2-7
2.7 COMMUNICATIONS ANTENNA INSTALLATION NOTES................................................................... 2-8
2.7.1 AUDIO ACTIVE OUTPUT ................................................................................................. 2-8
2.8 PMA8000 PIN ASSIGNMENTS ......................................................................................................... 2-9
2.9 POST INSTALLATION CHECKOUT ................................................................................................. 2-10
2.10 UNIT INSTALLATION ................................................................................................................... 2-10
2.11 OPERATIONAL CHECKOUT ......................................................................................................... 2-10
2.11.1 REQUIRED TEST EQUIPMENT ..................................................................................... 2-10
2.11.2 AUDIO PANEL TEST.................................................................................................... 2-10
2.11.3 MARKER CHECKOUT.................................................................................................. 2-11

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page ii Revision 9, June 2005
2.11.4 TEL CHECKOUT ......................................................................................................... 2-11
2.11.5 INTERNAL RECORDER CHECKOUT (OPTIONAL)......................................................... 2-11
2.12 FINAL INSPECTION...................................................................................................................... 2-11
Section III OPERATION........................................................................................... 3-1
3.1 SCOPE............................................................................................................................................ 3-1
3.2 POWER SWITCH (1) (EMG-FAIL SAFE OPERATION) .................................................................... 3-1
3.3 MICROPHONE (2) (XMT) SELECTION (ALL MODELS) .................................................................. 3-1
3.3.1 SWAP MODE (SWITCH FROM COM 1 TO COM 2 REMOTELY) ......................................... 3-2
3.4 AUDIO SELECTOR (4)...................................................................................................................... 3-2
3.4.1 SPEAKER AMPLIFIER (5)................................................................................................. 3-2
3.5 SPLIT MODE .................................................................................................................................... 3-3
3.5.1 MUTE BUTTON, SPLIT MODE ICS (6) ............................................................................ 3-3
3.6 INTERCOM OPERATION .................................................................................................................. 3-3
3.6.1 INTELLIVOX® VOX-SQUELCH ....................................................................................... 3-3
3.6.2 INTERCOM VOLUME CONTROL (7)................................................................................. 3-4
3.6.3 INTERCOM MODES (8).................................................................................................... 3-4
3.7 TELEPHONE MODE (9).................................................................................................................... 3-5
3.8 MARKER BEACON OPERATION (10)............................................................................................... 3-6
3.9 INTERNAL RECORDER SYSTEM (OPTION 1)................................................................................... 3-6
3.10 OPERATION ................................................................................................................................... 3-6
Section IV- Warranty and Service .............................................................................4-1
4.1 WARRANTY ..................................................................................................................................... 4-1
4.2 FACTORY SERVICE.......................................................................................................................... 4-1
Appendix A External PTT Hook Up ........................................................................... A
Appendix B – PMA 8000 Installation Drawings..........................................................B
Appendix C, J1 Interconnect ........................................................................................C
Appendix D, J2 Connector Interconnect...................................................................... D
Appendix E- Instructions for FAA Form 337 and continuing airworthiness ...............E
9.1 INSTRUCTIONS FOR FAA FORM 337, AUDIO PANELS ......................................................................E
9.2 INSTRUCTIONS FOR CONTINUING AIRWORTHINESS, AUDIO SYSTEM..............................................E
Appendix F RTCA DO160D Environmental Qualification Form................................ F
Rev Date Change
1 3/25/04 1st Release
2 5/5/04 Clarify/correct installation kit, added note regarding the screw lengths.
3 5/13/04 Change connector back shells to 1-piece, made left/right phasing consis-
tent throughout and corrected section 2.4.3.
4 6/11/04 Change front panel pictures and button layout
5 8/23/04 Corrected P/N, text in section 2.4.1
6 11/19/04 Clarified power wiring in section 2.4.3 and figure 2-1
7 3/16/05 Added list of required test equipment in section 2.11
8 5/24/05 Corrected text description for Unswitched 3 & 4, sect 2.4.10
9 6/22/05 Added note to section 2.4.13 for DME on AUX and logic switching

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 1-1 Revision 9, June 2005
Section I GENERAL INFORMATION
1.1 INTRODUCTION
The PMA8000 represents another evolutionary step in cockpit audio control and intercommunications util-
ity. Using our patented IntelliVox® design, this unit eliminates the requirements for intercom squelch ad-
justments. The unit is designed for outstanding ergonomics and visually defined mode annunciation and
selection.
Before installing and/or using this product, please read this manual completely. This will ensure that you
will take full advantage of all the advanced features in the PMA8000.
1.2 SCOPE
This manual provides detailed installation and operation instructions for the PS Engineering PMA8000-
series of Audio Selector Panel/Intercom Systems. This includes the following units:
Model Description Part Number
PMA8000 Stereo Audio Selector Panel with Marker Beacon 050-890-0100
Option 1 Same as above with Digital Recorder added 050-890-0200
Where the functions are identical to all units, it will be referred to herein as a PMA8000. Otherwise, the
applicable units will be specified.
1.3 EQUIPMENT DESCRIPTION
The PMA8000-series is a state of the art audio isolation amplifier and audio selector that contains an auto-
matic voice activated (VOX) intercom system. It can switch two transceivers (Com 1, Com 2 ) and six re-
ceivers (Nav 1, Nav 2, ADF, DME, MKR and AUX).
A full duplex TEL mode allows the PMA8000 to act as an audio interface between aircraft headphone and
microphones and specific aircraft approved (FAA/FCC) cellular telephone equipment.
Warning : Use of non-aviation approved cellular telephone equipment may be prohibited by regulation.
PS Engineering is not responsible for unauthorized airborne use of cellular telephones.
For airborne use, the PMA8000 must be interfaced with an approved system.
There are four unswitched inputs, available for traffic or EGPWS, autopilot disconnect, and/or radar al-
timeter warning.
Push buttons select the receiver audio source provided to the headphones. A SPR button allows the user to
listen to the receiver(s) selected on the cabin speaker. Except for the unswitched inputs, all speaker audio is
muted during transmit. All Unswitched inputs are always presented to the aircraft speaker.
Push button switches selects one of the communication transceivers for the pilot and copilot position, and
allows radio transmission. In "Split Mode" the PMA8000 has the ability to allow the pilot to transmit on
com 1 while the copilot can transmit on com 2. A fail-safe mode connects the pilot headphone and micro-
phone to COM 1 if power is removed for any reason, or if the power switch is placed in the Off (Fail-safe)
position.
A six-station voice activated (VOX) intercom is included in the PMA8000. This system has PS Engineer-
ing’s patented IntelliVox® circuitry that eliminates manual adjustments. The system contains six separate
VOX mic circuits, and only opens the microphone channel in use.
The intercom system incorporates pilot isolate, all and crew modes, two independent stereo music inputs
with "Soft Mute," and flashing LED indications for transmit indications. Intercom control is through two
concentric front panel volume controls and a pushbutton intercom mode switch. The small volume knob

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 1-2 Revision 9, June 2005
controls the intercom level for the pilot and copilot, while the large knob controls the passenger intercom
volume. Intercom squelch is automatic.
A 3-light Marker Beacon receiver is integrated in the PMA8000. This provides the necessary Marker Bea-
con lights and audio indications necessary for an Instrument Landing System (ILS) approach. A pushbut-
ton labeled MKR allows the pilot select high or low sensitivity as well as test and mute modes.
1.4 APPROVAL BASIS –
TSO Approval.
The PMA8000-series Audio Selector Panels are FAA approved under TSO C50c (Audio Amplifiers) and
TSO C35d (Marker Beacon Receivers).
All systems comply with relevant portions of EUROCAE RTCA MPS WG No. 7/70, DO-143 and (Marker
Beacon Receivers), ED-14C/DO-160C (Environmental Conditions and Test Procedures for Airborne
Equipment), ED12B/DO-178B, Level D (Software Considerations for Airborne Equipment) and ED-
18/DO-214 (Audio Systems Characteristics and Minimum Operational Performance Standards for Aircraft
Audio Systems).
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 opera-
tion.
1.5 SPECIFICATIONS
TSO COMPLIANCE
Marker Beacon: C35d, Class A
Audio Selector/Intercom: C50c, Class A
APPLICABLE DOCUMENTS: RTCA/DO-214 RTCA/DO-143 RTCA/DO-160D
RTCA/DO-178B DO-254
ENVIRONMENTAL Qualifications: A1D1CABSMXXXXXXZBABATBXXE2XXX
Operating Temperature Range: -15º C to 55ºC
Altitude: Up to 50,000 feet in an non-pressurized area
DIMENSIONS: Height: 1.3 in. (3.3 cm) Width: 6.25 in. (16.9 cm)
Depth behind panel 7.15 in. (18.16 cm)
WEIGHT
PMA8000 Unit
Rack with connectors
1.34 lb. (0.61 kg)
0.51 lb. (0.24 kg)
POWER REQUIREMENTS (Including Internal Lighting):
Voltage: 11 to 33 VDC
Maximum Current: 2.5 Amp (Externally protected by a 5A pull-type
breaker)

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 1-3 Revision 9, June 2005
Audio Selector Specifications
Audio selector panel input impedance: 510 Ω
Input Isolation: -60 dB (min.)
Speaker Muting: -60 dB (min.)
Speaker Output (into 4 Ω) with no clipping
14 VDC:
28 VDC:
3 Watts (min.)
10 Watts (min.)
Receiver Inputs: 9 (Com 1, Com 2, TEL, Nav 1, Nav 2, ADF,
DME, MKR, AUX)
Unswitched Inputs: 4
Transmitter Selections:4 (Com 1, Com 2, TEL
Com1/2)
Speaker Impedance:4 Ω
Headphone Impedance: 150 – 1000 Ω
Headphone Output: 38 mW each headset, no clipping <1% THD typi-
cal
Microphone Impedance: 150 - 600 Ω
Intercom Specifications
Intercom Positions: 6 places (with individual IntelliVox® circuits)
Music Inputs: 2, (Independent, Stereo)
Music Muting: >-30 dB "Soft Mute" when Com or intercom active.
Distortion: <1% THD @ 38 mW into 150Ω
Mic Freq. Response, 3 dB: 300 Hz - 6000 Hz
Music Freq. Response, 3 dB: 10 Hz – 26 kHz
MARKER BEACON RECEIVER:
Frequency: 75 MHz Crystal Controlled
Sensitivity:
Low:
High:
Capable of: (preset at factory for field application)
1000 µVolts (Hard) (360 to 570 µV soft)
200 µVolts (Hard) (130 to 200 µV soft)
Selectivity: -6 dB at ±10 kHz
-40 dB at ±120 kHz
External Lamp Output: 7.5 (±4 VDC unloaded, at maximum brightness) VDC
positive when active, max. current 125 mA
MM Sense: Active high (4.5 ± 1.0VDC)

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 1-4 Revision 9, June 2005
1.6 EQUIPMENT SUPPLIED
1 ea. of the following units:
Model Description Part Number
PMA8000 PMA8000 Audio Panel with Marker Beacon and Stereo intercom. 050-890-0100
PMA8000 with option 1 Add Internal recorder to PMA8000 050-890-0200
PMA8000 Installation Kit: 250-890-0000
Description Quantity Part
Number
PMA8000 installation rack assembly 1 430-890-0040
PMA8000 Rack back plate 1 430-890-0050
44-pin connector kit 2 120-891-2045-
Backshell, connector 2 625-025-2465
4 40 X 7/16 screw w/nylon patch 4 475-440-0007
4 40 X 1/4 screw w/lock washer 4 475-440-0004
4-40 Lock Nut 5 475-013-0001
Solder Lug 1 475-009-0001
Cable Clamp 1 625-001-0002
#6-32 x ½” Flat head Philips screw 6 475-632-0012
#6-32 Clip Nut 6 475-630-0002
1.7 EQUIPMENT REQUIRED BUT NOT SUPPLIED
a. Circuit Breaker: 1 ea; 5 amp PULL TYPE REQUIRED for PMA8000
a) Speaker, 4 Ω
b) Headphone Jacks (Stereo, as Required)
c) Microphone Jacks (as Required)
d) Headphones, 150 Ω(Stereo), up to 6 as required
e) Microphones, up to 6 as required
f) Marker Antenna (75 MHz, VSWR <1:1.5, and appropriate for the airspeed)
g) Interconnect Wiring
1.8 LICENSE REQUIREMENTS
None

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 2-1 Revision 9, June 2005
Section II - Installation
2.1 GENERAL INFORMATION
2.1.1 SCOPE
This section provides detailed installation and interconnection instructions for the PS Engineering
PMA8000-Series Audio Selector Panel/Intercom/ with internal Marker Beacon.
Please read this manual carefully before beginning any installation to prevent damage and post-installation
problems. Installation of this equipment requires special tools and knowledge.
2.1.2 Certification Requirements
NOTE
The PMA8000 requires specialized knowledge and tools for an effective installation. An
appropriately rated Certified Aircraft Repair Station must install this equipment in ac-
cordance 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 in-
dividual or agency will void the warranty, and may result in an unairworthy installation.
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 com-
ponents supplied with the list in Section 1.6 (B). 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 ac-
cessories 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 Engi-
neering 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 PMA8000 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 ade-
quate cooling air provided.
2.3.2 Mounting Requirements
The PMA8000 must be rigidly mounted to the instrument panel of the aircraft structure and within view
and reach of the pilot position(s). Installation must comply with FAA Advisory Circular AC 43.13-2A. The
unit may be mounted in any area where adequate clearance for the unit and associated wiring bundle exist.
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.
2.3.3 Audio Panel Mounting Rack Installation
Remove the unit from the mounting tray by unscrewing the 3/32" hex-head screw that is in the center of
the unit. Use caution to avoid hitting the photo-detector lens. Carefully slide the unit free of the tray. Set
the unit aside in a safe location until needed. Install the tray using six clip nuts (475-630-0002), and six

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 2-2 Revision 9, June 2005
FHP 6-32 x ½" screws (475-632-0012). The audio selector panel must be supported at front and rear of the
mounting tray.
2.3.4 Audio Panel Tray and Connector Assembly
The rack connectors mate with two 44-pin connectors in the PMA8000. The connectors are a sub miniature
crimp-type, and require the use a hand crimp tool, from table below (or equiv.). The connectors are
mounted to the tray back plate with #4-40 screws (475-440-0007), from the inside of the tray. Ensure that
proper strain relief and chafing precautions are made during wiring and installation, using the cable clamp
(625-001-0002).
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 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 43.13-2A 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.
2.4.1 Noise
Due to the variety and the high power of radio equipment often found in today's general aviation aircraft,
there is a potential for both radiated and conducted noise interference.
The PMA8000 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. There must be at least 13.8 VDC present at the connec-
tor, J2 pins 8 & 9, of the PMA8000 for the power supply to work in its designed regulation. Otherwise, it
cannot adequately attenuate power line noise. Shielding can reduce or prevent radiated noise (i.e., beacon,
electric gyros, switching power supplies, etc.) However, installation combinations can occur where inter-
ference is possible. The PMA8000 was designed in a RFI hardened chassis and has internal Electromag-
netic 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
2- or 3-conductor, shield wire as shown on the installation-wiring diagram.
The shields can be daisy-chained together, and then connected to a ground lug mounted on the corner of
the back plate.
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.

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 2-3 Revision 9, June 2005
NOTE:
Adding a high-performance audio control system, particularly in conjunction with high-performance active
noise canceling headsets, cannot improve on older avionics that were designed for cabin-speaker use. PS
Engineering makes no claim that the audio panel will provide a noise-free audio quality under all installa-
tion conditions, particularly with older avionics.
2.4.2 Existing GMA340 Installation
If the installation replaces a GMA340, no changes are required except to incorporate the new capabilities
of the PMA8000.
2.4.3 Power
The PMA8000-Series are compatible with both 14 and 28 Volt DC systems. A five (5) Amp circuit breaker
is required for all installations. Power and ground wires should be #22 connected to J2 Pins 8 and 9. Con-
nect airframe ground to J2 Pin 10 and 11 only. No dropping resistors are required.
2.4.4 Communications Push-to-Talk
An important part of the installation is the PTT (Push-To-Talk) switches that allow the use of your aircraft
communications radio for transmissions. There are three typical configurations that can be used. Select the
case that best fits the installation. Only the person who presses their PTT switch will be heard over the ra-
dio. If the pilot and copilot both use the PTT, the only pilot position has access to the radio. The pilot posi-
tion will have PTT control regardless of the mic selector switch or copilot PTT when the PMA8000 is in
the OFF/EMG mode.
CASE I: PTT is built into both pilot and copilot yokes.
CASE II: PTT is in pilot yoke only. This configuration requires a modified external PTT switch plugged
into the copilot's microphone jack. (See Appendix A). When the copilot's PTT is pressed, the intercom
switches the microphone audio from pilot to copilot mic.
CASE III: No built in PTT. This requires two built in PTTs to be installed, or modified external PTT
switches to be used. Modify external PTT as required. See Appendix A.
2.4.5 Audio Panel interface
The PMA8000 is designed to interface with standard aircraft avionics, and presents a 500Ωreceiver im-
pedance. For best results, a twisted-shielded cable is recommended from the avionics audio source to the
audio panel, with the shield grounded at the audio panel 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 panel to the radio ground, using one conduc-
tor of the twisted-shielded cable.
2.4.5.1 Speaker Load
The PMA8000 contains one speaker amplifier. Some units with internal speaker amplifiers, such as the
King Radio KX170-series, require a resistive load to prevent damage if their speaker amplifier is not used.
Connect the speaker output from the unit to the COM 2 Speaker load input on the PMA8000 ( J1 27 WRT
28). The speaker load is 16 Ω, 3W.
2.4.6 TEL (Duplex) Function for Cell Phones
This mode is designed to operate with telecommunications systems, such as the AirCell Guardian 1000.
Audio streams selected by the intercom mode are provided to the Tel output, and audio from Tel is pre-
sented to the headset. This allows a telephone-like audio interface.
The TEL mode in the PMA8000 is also compatible with many cellular telephones with hands-free headset
interfaces. A 1/8” or 3/32” jack can be installed on the aircraft panel, and interfaces with the PMA8000 as
shown: A patch cord (3/32” to 3/32”) is available from PS Engineering under P/N 425-006-7026.

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 2-4 Revision 9, June 2005
3/32" Cellular Jack
COM 3 Mic Input
Com 3 Audio
Audio Lo
Cellular Plug (typical)
Tip= Microphone out
Ring= Speaker audio
Base=Ground
This is a typical interconnect
PS Engineering does not guarantee
compatability in all cases.
Cellular Phone
Interconnect
Figure 2-1 Cellular telephone interface
Unauthorized use of unapproved cellular telephone devices in aircraft is subject to FCC enforcement
action, which may include a $10,000 fine per incident. PS Engineering, Inc. does not endorse using
unapproved cellular telephone equipment in flight, and takes no responsibility for the user’s action.
PS Engineering does not guarantee compatibility with personal cellular telephones. For a list of
phones that have been tested, visit www.ps-engineering.com.
2.4.7 Transmit Interlock
Some communications transceivers use a transmit-interlock system. To fully utilize the Split Mode feature,
this function must be disabled. Consult that manufacturer's installation manual.
2.4.8 Patented "Swap" Mode
When a momentary, normally open, push-button switch is connected between pin 20 on the J2 connector
and aircraft ground, the user can switch between Com 1 and 2 by depressing this switch without having to
turn the mic selector switch. This yoke-mounted switch eliminates the need to remove your hands from the
yoke to change transceivers. The transfer of TX indication from Com 1 to Com 2 shows that the swap has
been initiated, there is no dedicated swap indicator.
2.4.9 Backlighting
The PMA8000 has an automatic dimming of the pushbutton annunciation LEDs and marker lamps con-
trolled by a photocell. Control of the unit backlighting is through the aircraft avionics dimmer For 14 V
aircraft, connect J2 Pins 6 and 7 to the aircraft dimmer bus, and pin 5 to ground. For 28-volt systems, con-
nect pin 7 to the aircraft dimmer, and pins 5 and 6 to ground.
If an external dimmer control is not used, a constant back light illumination can be established for night-
time viewing. Pin 6 or 7 (depending on system voltage) must be tied to power (J1, pin 8 or 9) for the back
lighting system to work. The photocell mounted in the unit face will automatically adjust the intensity of
the push-button annunciator LEDs.
2.4.10 Unswitched inputs
J1, pins 31, 29 and J2 pin 15 are unswitched, unmuted inputs # 1, 3 and 4, respectively. These inputs are
presented to the pilot and copilot regardless of the audio configuration, and will always mute the enter-
tainment inputs. These 510Ωinputs can be used for altimeter DH audio, GPS waypoint audio, autopilot
disconnect tones, or any other critical audio signal. Unswitched #1 is always presented to the speaker.
Unswitched #2, J1 pin 44 is unswitched, but muted (controlled by the speaker switch), and suitable for air-
to-ground (Flitefone) telephone ringer This input is not related to the cellular telephone interface.
Unswitched 3 and 4 inputs are always presented to the crew headphones and to the aircraft speaker.
NOTE: These inputs are fixed (1:1), and any audio level adjustments must be made at the input source.

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 2-5 Revision 9, June 2005
2.4.11 Public Address Mode
By pressing the Mute and SPR pushbuttons at the same time, the PMA8000 will be placed into public ad-
dress (PA) mode. In this mode, both Com 1 and Com 2 receive indicators will blink, alerting the pilot that
when he presses his PTT switch he will be talking over the cockpit speaker. Copilot will still continue on
the selected COM radio.
When in the PA mode, J2 Pin 19 will go low, providing a digital logic level that can be used to incorporate
a speaker-switching scheme. This can control some switching means such as a relay that would transfer the
speaker output amplifier from the cockpit speaker to drive another cabin speaker. If the PA mode is used
with a microphone in proximity to an active cockpit speaker, feedback might result.
2.4.12 PA Mute (J2, Pin 12)
Pin 12 of J2 is a TTL logic output that is pulled low during PTT operation. This serves as an input to exter-
nal public address system to prevent feedback during transmissions.
2.4.13 Miscellaneous Logic Output (J2, Pin 18)
Pin 18 of the J2 connector is pulled to ground whenever the AUX button is depressed. This serves as a
control line for external devices, such as an entertainment system that the pilot wishes to control.
This pin can also be used to control passenger Karaoke Mode, by connecting to pin 13 of the J2, or as a PA
cockpit/cabin speaker relay control.
NOTE: J2, Pin 18 should NOT be used if the AUX is going to be used to switch DME or auxiliary audio.
2.4.14 Intercom wiring
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,
MIL-spec cable as shown. Connect the shields at the audio panel end only, and tie to the audio low inputs
as shown.
NOTE: The intercom harness can be custom made by PS Engineering, Inc. Simply call the factory or
www.ps-engineering.com to obtain a wire harness work sheet. The harness will be made to your specifica-
tions and fully functionally tested. Harness can be ordered with jack, or without the intercom jacks in-
stalled, for easier wire routing through the aircraft.
2.4.14.1 Entertainment Input
The PMA8000 has two INDEPENDENT music inputs. Entertainment input number 1 is J2 pins 23 (left
channel) and 24 (right channel), with respect to pin 25, and is provided to the pilot and copilot. Entertain-
ment number 2 is provided to the passengers at all times, and is connected to 26 (left channel), 27 (right
channel), with respect to 28.
Entertainment 1 and 2 must be connected together in order for all positions to hear the same music source.
We recommend installing a DPDT switch to allow isolation of the music source to the crew.
Ent. #1 Input
Alternate Music Interconnect
Note 7
Ent. #2 Input
24
23
25
27
26
28

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 2-6 Revision 9, June 2005
Music interconnect for Music 1 to drive both inputs
23
24
25
Ent. #1 Input
26
28
27
Alternate Music Interconnect
Ent. #2 Input
Music interconnect for Music 2 to drive both inputs
NOTE: Use the low level output of any additional entertainment device to connect to
the audio panel. Maximum signal level is 3 VAC p-p. DO NOT use a speaker-level
output, this will cause internal damage in the audio panel.
2.4.14.1.1 Entertainment muting
The PMA8000-system incorporates a "Soft Mute" system. This will mute the entertainment devices during
ICS or radio conversation.
Any signal appearing in the unswitched audio inputs will always mute the entertainment sources, even
though the passengers may not hear the audio tone itself.
Press the Mute switch to activate the Karaoke mode (disabling crew SoftMute™), This allows the pilot to
place the entertainment into the background while having the radios in the foreground. This eliminates the
constant interruption of the music while still having the radios a priority.
Caution: Local oscillators and internal signals from entertainment equipment can cause undesired interfer-
ence with other aircraft systems. Before takeoff, operate the entertainment devices to determine if there is
any adverse effect within the aircraft systems. If any unusual operation is noted in flight, immediately
switch off the entertainment devices.
All additional entertainment devices must be switched off for both takeoff and landing.

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 2-7 Revision 9, June 2005
2.4.14.1.2 Entertainment 2 Mute (J2 Pin 13 & 14)
Connecting J2 pin 13 to pin 14 (or ground) through a SPST switch places the entertainment #2 music
source into the Karaoke Mode. In this mode, incoming music and intercom conversation will not mute the
music for the passengers’ intercom net. This allows uninterrupted music during casual conversation and at
times when radio communications are of lesser importance.
See section 2.4.14 for alternative music connection to allow the passengers and crew to use the same input.
If desired, the AUX button can act as the passengers’ mute control. Connect J2 pin 18 (AUX logic) to J2
pin 13 (Entertainment. 2 Muteinhibit). This is NOT recommended if AUX is also used to switch audio.
2.4.15 Playback button Installation (J2, Pin 22- Option 1, ONLY)
To activate the Recording System playback, a momentary push button switch is required. This switch can
be located anywhere in cockpit convenient to the pilot's reach. The switch must be connected to pin 22 of
J2 of the PMA8000, and ground
2.5 Marker Beacon Installation
2.5.1 Marker Antenna Installation
A marker beacon antenna, appropriate to the type and speed of the aircraft, is required (not included). Re-
fer to aircraft and antenna manufacturer's installation instructions, as well as AC43.13-2A (or later revi-
sion), Chapter 3, for information on proper antenna installation techniques. The marker beacon antenna
must be mounted on the bottom of the aircraft.
2.5.2 External Marker Lights
For installations that require external marker beacon lights, there are three outputs that can drive 12-Volt
lamps only. The external output lamps are driven high (typically +9 VDC ±1.5 VDC unloaded, at MAX
brightness) when active. Maximum source current per lamp is 125 mA. Voltage varies with photocell dim-
ming.
2.5.3 Middle Marker Sense (Marker version)
A Middle Marker Sense output signal is available from the 8000 to flight control systems. This function
will not operate during the test mode. This output will go to +4.5 VDC (±1.0 VDC) when a valid Middle
Marker signal is received. This output is J1, pin 39.
2.6 Adjustments
The PMA8000 is factory adjusted to accommodate the typical requirements for most aircraft configura-
tions. There are three adjustments in the top cover that allow the installer to tailor the specific functions.

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 2-8 Revision 9, June 2005
TEL
VOL
SPR
VOL
MKR
VOL
Figure 2-2- PMA8000 Adjustments
• Speaker Volume- Turn adjustment clockwise to increase cabin speaker output.
• Marker Beacon Volume, turn adjustment counterclockwise to increase marker beacon audio level.
• TEL volume, turn adjustment Clockwise to increase the telephone audio.
2.7 Communications Antenna Installation Notes
For best results while in Split Mode, it is recommended that the one VHF communications antenna is lo-
cated on top of the aircraft while the other communications antenna is installed on the bottom. Any antenna
relocation must be accomplished in accordance with AC 43.13-2A, aircraft manufacturers’ recommenda-
tions and FAA-approved technical data.
Warning:
It is probable that radio interference will occur in the split mode when the frequencies of the two air-
craft radios are adjacent, and/or the antennas are physically close together. PS Engineering makes no
expressed or implied warranties regarding the suitability of the PMA8000 in Split Mode.
2.7.1 Audio Active Output
Pin 24 on the J1 connector (and PA Mute Pin 12 on J2) should be connected to Apollo CNX80 for audio
message prioritization, refer to CNX80 installation manual for details.
Front
of unit
NOTE:
If top cover is removed
for ANY reason,
y
ou
MUST replace the cover
screws with the proper
length, otherwise dama
g
e
will result.
Shorter Screw

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 2-9 Revision 9, June 2005
2.8 PMA8000 Pin assignments
J1 Function J2 Function
1 Mkr Ant 1 Pilot Phones Lo
2 Mkr Ant Lo 2 Copilot Phones Lo
3 Telephone Audio in 3 Copilot Phones (L)
4 Telephone Lo 4 Copilot Phones (R)
5 Telephone Mic Audio 5 Lights lo
6 Telephone Mic Key 6 14/28 V Lights
7 ADF Audio In 7 14/28 V Lights
8 ADF Audio Lo 8 Aircraft Power
9 Com 1 Audio 9 Aircraft Power
10 Com 1 Audio Lo 10 Aircraft Ground
11 Com 1 Mic 11 Aircraft Ground
12 Com 1 Mic Key 12 PA Mute
13 Com 2 Audio 13 Mute Inhibit
14 Com 2 Audio Lo 14 Mute Inhibit Lo
15 Com 2 Mic 15 Unswitched #4
16 No Connect 16 Pilot Phones (L)
17 Nav 1 Audio 17 No connect
18 Nav 1 Audio Lo 18 Misc (AUX) logic output
19 Nav 2 Audio 19 PA Enable
20 Nav 2 Audio Lo 20 Swap
21 DME Audio 21 Swap Lo
22 DME Audio Lo 22 IRS Playback
23 Auxiliary Audio Input 23 Music 1 (L)
24 CNX80 Inhibit 24 Music 1 (R)
25 No connect 25 Music 1 Lo
26 No connect 26 Music 2 (L)
27 Com 2 Speaker Load 27 Music 2 (R)
28 Com 2 Speaker Load 28 Music 2 Lo
29 Unswitched Audio 3 29 Remote Enable
30 Com 2 Mic Key 30 IR Port Out
31 Unswitched # 1 31 Pilot Phones(Rt)
32 Unswitched #1 Lo 32 Copilot Mic Audio
33 Pilot Mic Audio 33 Copilot Mic PTT
34 Pilot Mic PTT 34 Copilot Mic Lo
35 Pilot Mic Lo 35 Pass 1 Mic Audio
36 Ext IM MKR 36 Pass 1 Mic Audio Lo
37 Ext OM MKR 37 Pass 2 Mic Audio
38 Ext MM MKR 38 Pass 2 Mic Audio Lo
39 MM Sense 39 Pass 3 Mic Audio
40 Pass HP (L) 40 Pass 3 Mic Audio Lo
41 Pass HP (R) 41 Pass 4 Mic Audio
42 Pass HP Lo 42 Pass 4 Mic Audio Lo
43 Unswitched #2 Lo 43 Speaker Lo
44 Unswitched #2 Audio 44 Speaker Output

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 2-10 Revision 9, June 2005
2.9 Post Installation Checkout
After wiring is complete, verify power is ONLY on pins 8 and 9 of the J2 and airframe ground on connec-
tor pins 10 and 11. Failure to do so will cause serious internal damage and void PS Engineering's war-
ranty.
2.10 Unit Installation
To install the PMA8000, gently slide the unit into the mounting rack until the hold-down screw is engaged.
While applying gentle pressure to the face of the unit, tighten the 3/32" hex-head in the center of the unit
until it is secure. DO NOT OVER TIGHTEN.
Caution: Apply steady pressure to the bezel while screwing the unit into the tray to
ensure even seating of the unit and connectors.
Warning: Do not over-tighten the lock down screw while installing the unit in tray.
Internal damage will result.
2.11 Operational Checkout
2.11.1 Required Test Equipment
In order to return an aircraft to service after installation of the PMA8000, the installer must have access to
a Marker Beacon signal generator:
a. IFR NAV401L, NAV402AP, IFR4000
b. TIC T-30D, T-36C
Equivalent test equipment is acceptable as long as the testing requirements can be met.
2.11.2 Audio Panel Test
NOTE: The IntelliVox® is designed for ambient noise levels of 80 dB or above. Therefore some clipping
may occur in a quiet cabin, such as without the engine running, in a hangar. This is normal.
1. Apply power to the aircraft and avionics.
2. Plug headsets into the pilot, copilot, and occupied passenger positions.
3. Verify fail-safe operation by receiving and transmitting on com 1 from the pilot position, with the au-
dio panel power off. The Com audio will be present in one ear cup only.
4. Switch on the unit by pressing the volume (VOL) knob.
5. Check intercom operation.
6. Push the Com 1 Xmt select button (lower row).
7. Verify that both of the Com 1 buttons light. Verify that transmit button LED (Light Emitting Diode)
near the mic selector is not blinking. If the LED is blinking, stop testing and troubleshoot the micro-
phone PTT installation.
8. Verify proper transmit and receive operation from the copilot position, noting that the copilot PTT
switch allows proper transmission on the selected transceiver. Verify that the Com 1 Xmt button blinks
when transmitting.
9. Verify that pushing the COM 2 button causes the button to illuminate, and the Com 2 receiver to be
heard. Verify operation on Com 1 from the pilot position.
10. Repeat for Com 2
11. Press and hold the Com 1 Xmt button. While holding the Com 1 button, press the Com 2 Xmt button.
This places the unit in “split Mode;” Verify that the pilot can transmit and receive on Com 1, while the
copilot transmits and receives on Com 2.

PS Engineering
PMA8000 Series Audio Selector Panel and Intercom System
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200-890-0000 Page 2-11 Revision 9, June 2005
12. Verify proper operation of all receiver sources by selecting them using the appropriate button. The
button illuminates to show which source is in use.
13. Push the SPR button. Verify that all selected audio is heard in the cockpit speaker. Verify that the au-
dio mutes when the mic is keyed.
14. Verify that the appropriate LED in the lower button row blinks when either push to talk is keyed.
15. Verify proper Intercom system operation in the ALL, ISO and CREW modes (see Table 3-1).
16. Verify that the audio selector panel system does not adversely affect any other aircraft system by sys-
tematically switching the unit on and off, while monitoring the other avionics and electrical equipment
on the aircraft.
2.11.3 Marker Checkout
1. Connect a ramp generator at the antenna end of the marker coax. With the unit under test in HI sensi-
tivity, verify that a 160 µV, modulated 95% with 1300 Hz, signal will illuminate the amber (M)
marker light, and that marker audio is present in the headphones when the Marker Audio (M) push-
button has been depressed. Select SPR for speaker to verify marker audio availability on the cabin
speaker. Verify that the white (I) and blue (O) lights will illuminate within ±3dB of the amber lamp,
with 3000 HZ and 400 Hz applied, respectively.
2. Repeat with the unit in LOW sensitivity, with 430 µVolts applied.
3. Connect the marker antenna and verify proper operation.
2.11.4 TEL Checkout
Press the TEL button. Verify that the pilot headset is connected to the cellular telephone system (if in-
stalled). Verify that by using the pilot side PTT, the pilot can transmit on the other selected radio (Com 1 or
Com 2).
When a wireless telecommunication system is installed, a dial tone will appear in the headset of the pilot
when the TEL selector is activated. The telephone function will place any person heard by the pilot on the
intercom, also heard on the telephone.
2.11.5 Internal Recorder Checkout (Optional)
With headset plugged into pilot’s side jacks, tune COM 1 to local frequency, such as FSS or ATC ground.
Select Com 1 on mic selector switch, and record at least five incoming radio transmissions.
This audio should only appear in the pilot’s headset, and only be incoming transmissions from the trans-
ceiver selected in the mic select switch. Depress the panel or yoke mounted playback switch, and verify
that messages play, in the order received. Repeat for COM 2, and COM 3 (if installed).
2.12 Final Inspection
Verify that the wiring is bundled away from all controls and no part of the installation interferes with air-
craft control operation. Move all controls through their full range while examining the installation to see
that no mechanical interference exists. Verify that the cables are secured to the aircraft structure in accor-
dance with good practices, with adequate strain relief. Ensure that there are no kinks or sharp bends in the
cables and coaxial cables. Verify that the cables are not exposed to any sharp edges or rough surfaces, and
that all contact points are protected from abrasion.
Complete logbook entry, FAA Form 337, weight and balance computation and other documentation as
required. Sample text for FAA Form 337, and instructions for continuing airworthiness can be found in
Appendix F.
Return completed warranty registration application to PS Engineering, or complete online at www.ps-
engineering.com.

PS Engineering
PMA8000 Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 3-1 Revision 9, June 2005
Section III OPERATION
GENERAL INFORMATION
3.1 SCOPE
This section provides detailed operating instructions for the PS Engineering PMA8000, Audio Selector
Panel/Intercom Systems. Please read it carefully before using the equipment so that you can take full ad-
vantage of its capabilities.
This section is divided into four sections covering the basic operating areas of the PMA8000 systems. They
are Communications Transceiver Selection, Audio Selector, Intercom, and Marker Beacon Receiver.
Figure 3-1 PMA8000 front panel
3.2 Power Switch (1) (EMG-Fail Safe Operation)
Unit power is turned on and off by pushing the volume knob. In the OFF or "EMG" position, the pilot is
connected directly to Com 1. This allows communication capability regardless of unit condition. Any time
power is removed or turned OFF, the audio selector will be placed in the fail-safe mode.
The power switch also controls the audio selector panel functions, intercom and marker beacon receiver.
3.3 Microphone (2) (XMT) Selection (All models)
There are four pushbuttons associated with the communications transceivers. The lower buttons (item 2)
control which transceiver is selected for transmit, the top row of COM 1 and COM 2 allows selection of
the receive audio.
The PMA8000 gives priority to the pilot’s PTT. If the copilot is transmitting, and the pilot presses his PTT,
the pilot’s microphone will be transferred to the selected com transmitter.
The PMA8000-Series has an automatic selector mode. Audio from the selected transceiver is automatically
heard in the headsets and speaker (if selected). You can check this function by switching from COM 1 to
COM 2 XMT mode and watch the selected RCV light on the selector change from COM 1 to COM 2. This
ensure the pilot will always hear the audio from the transceiver he is transmitting on.
When switching from COM 1 to COM 2, while COM 2 audio had been selected, Com 1 audio will continue
to be heard. This eliminates the pilot having to switch Com 1 audio back on, if desired.
When switching from COM 1 to COM 2 while Com 2 has NOT been selected, Com 1 audio will be switched
off. In essence, switching the mic selector will not effect the selection of Com receiver audio.
In TEL mode, the pilot microphone and headphones are connected to the cell phone. The pilot PTT will
switch the pilot mic to the selected com transceiver, and allow continued aircraft communications to con-
tinue.
The copilot will also be able to transmit on the other selected radio with his PTT as well.

PS Engineering
PMA8000 Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0000 Page 3-2 Revision 9, June 2005
Figure 2 PMA8000 Operating controls
NOTE: Placing the PMA8000 in–TEL–
The intercom mode pushbutton determines who is on the phone, and who is still on the intercom.
In ISO, only the pilot is on the phone, while the copilot and passengers remain on intercom. The pilot will
continue to hear all selected aircraft radios.
In the ALL mode, everyone will be on the phone, intercom, and hear aircraft radios, and:
In Crew mode, the pilot and copilot will be on the phone and hear aircraft radios, while the passengers will
be on intercom.
3.3.1 Swap Mode (Switch from Com 1 to Com 2 remotely)
With a yoke mounted, momentary switch, the pilot can change from the current Com transceiver to the
other by depressing this switch. To cancel "Swap Mode," the pilot may either press the yoke mounted
switch again, or select a different Com with the XMT buttons. .
3.4 Audio Selector (4)
Receiver audio is selected through seven momentary, push-button, backlit switches. You will always hear
the audio from the transceiver that is selected for transmit.
The users can identify which receivers are selected by noting which of the green switch LEDs are lit. Push
buttons labeled Nav 1, Nav 2, MKR (Marker), ADF and AUX (auxiliary) places those receivers into the
audio stream. DME audio (if present) will come through when the AUX button is selected. When one of
these buttons is pressed, the mode is active, and the LED will illuminate. Press the switch again and it will
be "off" and remove that receiver from the audio output.
3.4.1 Speaker Amplifier (5)
The "SPR" in the push-button section stands for speaker. This switch will place all selected audio on the
cockpit speaker when this switch is selected. NOTE: Except for the unswitched audio, the speaker ampli-
fier is not active in the "Split Mode”.
Unswitched audio input 1, (the input dedicated to autopilot disconnect, altimeter warning, etc.) will come
through the speaker regardless of the speaker button position. Unswitched audio input 2, (the input dedi-
cated to a lesser importance input such as GPS waypoint alert) will come through the speaker only when
the SPR mode is on. Consult your installer for more information.