9800 Martel Road
Lenoir City, TN 37772
www.ps-engineering.com
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Document P/N 200-780-0005
Revision 10, December 2012
Audio Selector Panel with Marker Beacon Receiver
High-fidelity Stereo Intercom
System Installation and Operation Manual
FAA-Approved TSO C50c, C35d
JAA-Approved JTSO C50c, 2C35d
Patented under one or more of the following; No. 4,941,187; 5,903,277;
6,160,496 and 6,493,450
PS Engineering, Inc. 2012 ©
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 (865) 988-9800, email avionics@ps-engineering.com.
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
1.4 APPROVAL BASIS -................................................................................................................. 1-2
1.5 SPECIFICATIONS.................................................................................................................... 1-2
1.6 EQUIPMENT SUPPLIED......................................................................................................... 1-3
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.......................................................................................................................... 2-3
2.4.2 EXISTING KMA-24 INSTALLATION ............................................................................... 2-3
2.4.3 EXISTING PMA6000 INSTALLATIONS............................................................................ 2-3
2.4.4 POWER ........................................................................................................................ 2-4
2.4.5 COMMUNICATIONS PUSH-TO-TALK.............................................................................. 2-4
2.4.6 AUDIO PANEL INTERFACE ............................................................................................ 2-4
2.4.7 COM 3 DUPLEX (TEL) FUNCTION FOR CELL PHONES................................................... 2-4
2.4.8 TRANSMIT INTERLOCK................................................................................................. 2-5
2.4.9 "SWAP" MODE ............................................................................................................. 2-5
2.4.10 BACKLIGHTING .......................................................................................................... 2-5
2.4.11 UNSWITCHED INPUTS ................................................................................................. 2-6
2.4.12 PA MUTE (J1, PIN 18)................................................................................................ 2-6
2.4.13 PUBLIC ADDRESS FUNCTION (J2, PIN 18) ................................................................... 2-6
2.4.14 CONTROL OUTPUT (J2, PIN A) ................................................................................... 2-6
2.4.15 INTERCOM WIRING..................................................................................................... 2-6
2.4.16 ENTERTAINMENT INPUT............................................................................................. 2-7
2.4.17 PMA7000B INTERCOM EXPANSION (J2, PINS P, S, AND C)......................................... 2-7
2.5 MARKER BEACON INSTALLATION ............................................................................................... 2-8
2.5.1 MARKER ANTENNA INSTALLATION .............................................................................. 2-8
2.5.2 EXTERNAL MARKER LIGHTS (MARKER VERSION) ........................................................ 2-8
2.5.3 MIDDLE MARKER SENSE (MARKER VERSION).............................................................. 2-8
2.5.4 MARKER AUDIO INPUT (NON-MARKER VERSION) ......................................................... 2-8
2.6 ADJUSTMENTS ............................................................................................................................. 2-8
2.7 COMMUNICATIONS ANTENNA INSTALLATION NOTES .................................................................. 2-9
2.7.1 HOOK SWITCHES ......................................................................................................... 2-9
2.8 PMA7000B PIN ASSIGNMENTS .................................................................................................. 2-10
2.9 POST INSTALLATION CHECKOUT............................................................................................... 2-11
2.10 UNIT INSTALLATION ................................................................................................................ 2-11
2.10.1 REQUIRED TEST EQUIPMENT ................................................................................... 2-11
2.10.2 OPERATIONAL CHECKOUT ....................................................................................... 2-11
2.10.3 RECEIVER SENSITIVITY ............................................................................................ 2-12
PS Engineering
PMA7000B Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-780-0005 Page ii Rev. 10, December 2012
2.11 CELLULAR INTERFACE CHECKOUT ......................................................................................... 2-12
2.12 FINAL INSPECTION................................................................................................................... 2-12
SECTION III OPERATION .......................................................................................................... 3-1
3.1 SCOPE ....................................................................................................................................... 3-1
3.2 POWER SWITCH (EMG-FAIL SAFE OPERATION) ......................................................................... 3-1
3.3 MICROPHONE (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 (ALL MODELS) ................................................................................................ 3-2
3.4.1 SPEAKER AMPLIFIER.................................................................................................... 3-2
3.5 SPLIT MODE ................................................................................................................................ 3-2
3.5.1 SPLIT MODE ICS.......................................................................................................... 3-3
3.6 INTERCOM OPERATION ............................................................................................................... 3-3
3.6.1 INTELLIVOX® VOX-SQUELCH...................................................................................... 3-3
3.6.2 INTERCOM VOLUME CONTROL .................................................................................... 3-4
3.6.3 INTERCOM MODES....................................................................................................... 3-4
3.6.4 ENTERTAINMENT INPUT............................................................................................... 3-5
3.7 TELEPHONE MODE ...................................................................................................................... 3-6
3.8 MARKER BEACON OPERATION (IF PRESENT)............................................................................... 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 7000B INSTALLATION DRAWING...........................................................B
APPENDIX C BOTTOM CONNECTOR INTERCONNECT ........................................................C
APPENDIX D TOP 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 DO160C (EUROCAE ED-14) ENVIRONMENTAL QUALIFICATION FORM ............... F
CROSS REFERENCE FOR BENDIX/KING KMA26 ................................................................... G
CROSS-REFERENCE FOR GMA340 ............................................................................................ G
Revision History
Rev By Date Change
1 GLP Dec. 2002 Clarified the AirCell Guardian Interface, added patent number to cover
2 GLP May 2003 Removed confusing part numbers, added Option 2 (No marker)
3 GLP Dec 2003 Added cell phone interconnect, CNX80 interface, removed POTS interface. Added x-reference to
KMA26 & GMA340
4 GLP March 2005 Clarify CNX80 interface, incompatible with Option 1
5 GLP March 2005 Added list of test equipment for marker beacon
6 GLP Nov. 2007 Added note for Fail Safe Channel
7 GLP January 2009 Remove DRAWS after PCB revision., Add ALT ICS Mode
8 GLP Feb 2010 Added detail on Com 3 adjustment §2.7
9 GLP May 2011 Added detail on Unswitched inputs #3 & 4 when replacing a KMA24
10 GLP Dec 2012 Removed hook switch connection from AUX enable, §2.4.14
PS Engineering
PMA7000B Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-780-0005 Page 1-1 Rev. 10, December 2012
Section I GENERAL INFORMATION
1.1 INTRODUCTION
The PMA7000B represents the next step in cockpit audio control and intercommunications utility. Using
proprietary IntelliVox® design, this unit eliminates the requirements for intercom squelch adjustments.
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 PMA7000B.
1.2 SCOPE
This manual provides detailed installation and operation instructions for the PS Engineering PMA7000Bseries of Audio Selector Panel/Intercom Systems. This includes the following units:
Model Description Part Number
PMA7000B Option 3 Stereo Audio Selector Panel with Marker Beacon 7000B- Opt. 3
1.3 EQUIPMENT DESCRIPTION
The PMA7000B-series 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 three transceivers (Com 1, Com 2
and Com 3) and six receivers (Nav 1, Nav 2, ADF, DME, MKR and AUX).
A duplex COM 3 mode (selectable at installation) allows the PMA7000B 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 PMA7000B must be interfaced with an approved system.
There are four unswitched inputs, available for traffic or EGPWS, autopilot disconnect, and/or radar altimeter 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.
Push buttons select one of the communication transceivers for the pilot and copilot position, and allows
radio transmission. In "Split Mode" the PMA7000B has the ability to allow the pilot and copilot to operate
different transceivers independently. The Com 3/TEL mode (selected at installation) allows the pilot to
use the audio panel for duplex operation, such as with specific cellular telephones. External switches permit telephone operation for the copilot and passengers.
A fail-safe mode connects the pilot headphone and microphone to COM 1 if power is removed for any
reason, or if the power switch is placed in the Off (Fail-safe) position. Unswitched input #1 is also connected to the pilot headset in Fail-safe mode.
A six-station voice activated (VOX) intercom is included in the PMA7000B. This system has PS Engineering’s exclusive 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 and crew modes, two independent stereo music inputs with
"Soft Mute," and flashing LED indicators for transmit indications. Intercom control is through two front
panel- mounted volume knobs and 3-position mode switch. The concentric volume controls the intercom
PS Engineering
PMA7000B Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-780-0005 Page 1-2 Rev. 10, December 2012
level for the pilot and copilot, while the outer knob controls the passenger intercom volume. Intercom
squelch is automatic.
An “Alternate Intercom Mode” is incorporated in PMA7000B beginning with a serial number starting
with “J”and above. This allows the passengers and crew to converse, but removes radio traffic from the
passengers’ headphones, and blocks passenger mics from the crew during radio receptions.
A 3-light Marker Beacon receiver is integrated in the PMA7000B. This provides the necessary Marker
Beacon lights and audio indications necessary for an Instrument Landing System (ILS) approach.
1.4 APPROVAL BASIS -
TSO Approval.
The PMA7000B-series Audio Selector Panels are FAA approved under TSO C50c (Audio Amplifiers) and
TSO C35d (Marker Beacon Receivers). In addition, they are approved by the Joint Airworthiness Authorities under JTSO C50C and JAR-TSO 2C35d.
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 (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 operation.
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-160C
RTCA/DO-178B
ENVIRONMENTAL Qualifications:
A1D1/CA(MN)XXXXXXBBBBTBKXX
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: 6.8 in. (17.3 cm)
WEIGHT (With Rack & Connectors): 1.5 lb. (0.54 kg)
POWER REQUIREMENTS (Including Internal Lighting):
Voltage: 11 to 33 VDC
Maximum Current: 2.5 Amp (Externally protected by a 3A pull-type
breaker)
PS Engineering
PMA7000B Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-780-0005 Page 1-3 Rev. 10, December 2012
Audio Selector Specifications
Audio selector panel input impedance:
510
Input Isolation: -60 dB (min.)
Speaker Muting: -60 dB (min.)
Speaker Output (into 4 ) with no clipping
14 VDC:
28 VDC:
3 Watts (min.)
10 Watts (min.)
Receiver Inputs: 9 (Com 1, Com 2, Com 3, Nav 1, Nav 2, ADF,
DME, MKR, AUX)
Unswitched Inputs: 4
Transmitter Selections: 5 (Com 1, Com 2, Com 3
Com1/2, Com1/3)
Speaker Impedance:
4
Headphone Impedance:
150 – 1000
Headphone Output: 38 mW each headset, no clipping <1% THD
Microphone Impedance:
150 - 600
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 150
Mic Freq. Response, 3 dB:
300 Hz - 6000 Hz
Music Freq. Response, 3 dB:
20 Hz - 18kHz
MARKER BEACON RECEIVER: (if equipped)
Frequency:
75 MHz Crystal Controlled
Sensitivity:
Low:
High:
Capable of: (preset at factory for field application)
1000 Volts (Hard) (360 to 570 V soft)
200 Volts (Hard) (130 to 200 V 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)
1.6 EQUIPMENT SUPPLIED
1 ea. of the following units:
Model Description Part Number
PMA7000B Opt 3 PMA7000B Audio Panel with Marker Beacon and Stereo intercom. 7000 (Opt 3 )
PMA7000B Opt 2 PMA7000B Audio Panel without Marker receiver 7000 Opt 2
PMA7000B Installation Kit: 250-007-0002
Description Quantity Part
Number
PMA7000 installation rack assembly 1 120-430-0420
Top Molex Connector Shell w/key, 44 pin, key 4/5 1 120-425-4402
Bottom Molex Connector Shell w/key, 44 pin, key 7/8 1 120-425-4400
Gold Plated Crimp Pins 88 425-001-0002
4 40 X 7/16 screw w/nylon patch 4 475-440-0007
Grounding bar 1 430-007-0001
6-32 X 3/4 pan head Phillips screw 2 475-632-0038
6-32 Nut Flat 2 475-632-0003
PS Engineering
PMA7000B Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-780-0005 Page 1-4 Rev. 10, December 2012
Installation Kit Description Quantity Part
Number
6-32 Lock Nut 2 475-632-0004
Cable Clamp 1 625-001-0002
#6-32 x ½” Flat head Phillips screw 6 475-632-0012
#6-32 Clip Nut 6 475-630-0002
Parts identification sheet 1 002-250-7028
Pilot’s Guide 1 202-070-0001.
1.7 EQUIPMENT REQUIRED BUT NOT SUPPLIED
a) Circuit Breaker: 1 ea; 3 amp PULL TYPE REQUIRED for PMA7000B
b) Speaker, 4
c) Headphone Jacks (Stereo, as Required)
d) Microphone Jacks (as Required)
e) Headphones, 150 (Stereo), up to 6 as required
f) Microphones, up to 6 as required
g) Marker Antenna (75 MHz, VSWR <1:1.5, and appropriate for the airspeed)
h) Interconnect Wiring
1.8 LICENSE REQUIREMENTS
None
PS Engineering
PMA7000B Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-780-0005 Page 2-1 Rev. 10, December 2012
Section II - Installation
2.1 GENERAL INFORMATION
2.1.1 SCOPE
This section provides detailed installation and interconnection instructions for the PS Engineering
PMA7000B-Series Audio Selector Panel/Intercom/ with internal Marker Beacon.
Please read this manual carefully before beginning any installation to prevent damage and postinstallation problems. Installation of this equipment requires special tools and knowledge.
2.1.2 Certification Requirements
NOTE
The PMA7000B 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.
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 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 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 PMA7000B 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 PMA7000B 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 43.13-2B.
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
PMA7000B Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-780-0005 Page 2-2 Rev. 10, December 2012
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 unit connectors mate directly with the circuit boards in the PMA7000B. The connectors are a Molex
crimp-type, and require the use of a Molex hand crimp tool, EDP P/N 11-01-0203, CR6115B (or equiv.).
The connectors are mounted to the unit tray 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). Secure the ground bar (430-007-0001), if desired using, #6-32 nuts
(475-632-0003) and #6-32 lock nuts (475-632-0004).
Figure 2-1 Audio Panel Tray Assembly Drawing
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.
120-430-0420
PS Engineering
PMA7000B Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-780-0005 Page 2-3 Rev. 10, December 2012
NOTE: PS Engineering can make a custom wiring harness for the intercom. Call 1-800-ICS-AERO or see
www.ps-engineering.com for details.
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 PMA7000B 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 bottom
connector, pin 20, of the PMA7000B 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 interference is possible. The PMA7000B 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
2- or 3-conductor, shield wire as shown on the installation wiring diagram.
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.
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 installation conditions, particularly with older avionics.
2.4.2 Existing KMA-24 Installation
If the installation replaces a KMA-24 (series -01, -02 or -03), the existing 44 pin connector can be used
for the bottom connector of the PMA7000B tray as is, providing it is properly installed and wired. If the
KMA 24 installation includes “External Speaker” or Internal Speaker” connections to J1 Pins X and U
respectively), these will have to be disconnected to avoid interference with the Unswitched inputs #3 and
#4.
No other changes are required except for external marker lights (see Section 3.7.2 for details). The "key"
in the existing connector must be located between pins 7 and 8. This connector will be used in the bottom
connector position. (See Appendix for complete wiring harness details.)
The existing ground bus may be reused for radio shield connections, if it was constructed so it can be relocated to the PMA7000B tray.
2.4.3 Existing PMA6000 installations
In 28-Volt aircraft, the dropping resistor may be removed, however, the 2 Amp breaker should be changed
to 3 Amp. If the old unit is stereo (PMA6000S or PMA6000MS), no rewiring is necessary except to add
additional features.
2.4.3.1 Stereo PMA7000B installations into monaural PMA6000, PMA6000M.
Installations replacing PMA6000 or PMA6000M require re-wiring of the top connector to accommodate
the stereo configuration. See appendixes for detailed interconnect information.
PS Engineering
PMA7000B Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-780-0005 Page 2-4 Rev. 10, December 2012
2.4.4 Power
The PMA7000B-Series are compatible with both 14 and 28 Volt DC systems. A two (2) Amp circuit
breaker is required for 14 VDC installations, and a three (3) Amp breaker for 28 VDC aircraft. Power and
ground wires must be a twisted #18 AWG pair. Connect airframe power ground to J1 (bottom connector)
Pin Z only. No dropping resistors are required.
2.4.5 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 radio. If the pilot and copilot both use the PTT, the only pilot position has access to the radio.
The pilot position will have PTT control regardless of the mic selector switch or copilot PTT when the
PMA7000B 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.
2.4.6 Audio Panel interface
The PMA7000B is designed to interface with standard aircraft avionics, and presents a 500 receiver
impedance. 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 conductor of the twisted-shielded cable.
2.4.6.1 Speaker Load
The PMA7000-series contains a 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 load input on the PMA7000B (J1, pins 19 and L, 16
and M. The speaker load is 16 , 3W.
2.4.6.2 Fail Safe Connection
The PMA7000B connects the pilot microphone and headphone directly to COM 1 input when power is
removed. The headphone failsafe is the RIGHT channel, connected to the TIP of the headphone jack, to be
compatible with monaural headphones. Unswitched input #1 (Bottom Connector pin T) is also provided to
the pilot headset, right channel, in fail-safe.
NOTE: The pilot headphone MUST be wired in accordance with Appendix C, Bottom connector Pin 3 to
Pilot headphone tip (right) to ensure proper failsafe operation. Verify failsafe operation in accordance with
Section 2.11.2, step 3.
2.4.7 Com 3 Duplex (TEL) Function for Cell Phones
As installed in the standard configuration, the PMA7000B Com 3 function operates conventionally. Pushing the Com 3 Xmt button places the receive audio from Com 3 in the headset and applies the pilot or
copilot microphone to the Com 3 when the appropriate PTT is activated.
If J2, Pin J is connected to aircraft ground, the PMA7000B is forced into Com 3-Duplex mode. Copilot
and passenger audio as selected by hook switches are provided to the COM 3 output, the PTT for Com 3 is
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