Air Comm Systems ACS 300A-101 User manual

Dual Audio Mixer Panel
Installation and Operations Manual
ACS 300A-101 Revision 1.3
Air Comm Systems, Inc
37610 Sky Canyon Dr., Hangar 51
Murrieta, CA 92563
Ph: 951-677-0101 ~ Fx: 951-677-0701
[email protected] ~ www.AirCommSystems.com

Air Comm Systems, Inc. Page 2
nInstallation
Physical and Operating Specifications Page 3
Physical Dimensions Page 4
Interface Schematic Page 5
nOperation
Front Panel Controls Page 6-7
Front Panel Controls Pictorial Page 8
Rear Panel Adjustment Pictorial Page 8
nInstructions for Continued Airworthiness
Instruction for Continued Airworthines Page 9
nWarranty Information
Warranty Information Page 10
ACS 300A-101 Installation and Operations Manual
Table of Contents

Air Comm Systems, Inc. Page 3
nPhysical Specifications
nOperating Specifications
SIZE: 6.31 in.(16.03 cm) W WEIGHT: 2.90 lb
2.62 in.( 6.65 cm) H
6.78 in.(17.22 cm) D w/ connector MOUNTING: Dzus rail mount
CONTROLS: Panel mounted - transmit = rotary switch, audio inputs = toggle switch
volume control = dual potentiometer
ILLUMINATION: Edge lit front panel per MIL-P-7738E, type 3. Capable of connection to
dimmer bus for adjustment. Amber transmit light indicates when unit is in
transmit mode.
INPUTS: 5 receive audio inputs per position. 6 transmit selections per position.
DUTY CYCLE: Continuous POWER REQUIREMENTS: 14V DC or 28V DC +/- 10%
MAXIMUM OPERATING ALTITUDE: 16,500 ft.(5029 m)
OPERATING TEMPERATURE RANGE: -40 C to +85 C (operating)
-65 C to +125 C (storage)
CURRENT DRAIN: 50 mA at 28V (standby) - 1.5 A at 28V (max. signal)
AUDIO OUTPUT: Minimum 250 mW into 600 ohms
FREQUENCY RESPONSE: Within 6 db - 300-3000Hz
ICS INPUT IMPEDANCE: 600 ohms
RECEIVER INPUT IMPEDANCE: 600 ohms - matched to receiver
INPUT ISOLATION: Not less than 45 db between inputs
AUDIO MUTING: Not less than 45 db during transmit/ICS (optional)
MIC SENSITIVITY: 300 mV for rated output
DISTORTION: Less than 10% at 1000 Hz for maximum output
ACS 300A-101 Installation and Operations Manual
Physical and Operating Specifications

Air Comm Systems, Inc. Page 4
nPhysical Dimension Outline
ACS 300A-101 Installation and Operations Manual
Physical Dimensions
Physical Installation
The ACS 300A is designed to be Dzus mounted and should be installed in the aircraft using the Installation
kit that was included with the unit. The above outline drawing of the unit with dimensions will facilitate the
installation. The Installation Kit consists of the following:
One (1) 37 pin AMP D-Subminiature female mating connector complete with crimp pins, hood, and slidelock.
One (1) 25 pin AMP D-Subminiature female mating connector complete with crimp pins, hood, and slidelock.
The connector pin configuration of the ACS 300A rear connector and the recommended wire size for the
aircraft cable harness is shown on the following page.

Air Comm Systems, Inc. Page 5
The ACS 300A wiring harness should be constructed of Tefzel aircraft wire (M22759/16 grade). Power
and ground wires should be 18 or 20 AWG, and all other wires may be 22 AWG. Shielded wires should
be used where noted. Adequate protection against wear and chafing should be taken by using a braided
cable sleeving or jacket. Before completing installation, verify that all cable connector pins are seated
properly and that the connector is securely mounted to the unit mating connector.
Pre-fabricated cable harnesses are available from Air Comm to expedite installation — consult our sales
department for details.
NOTE: Pins noted NC = No Connection.
nConnector Pin-out
ACS 300A-101 Installation and Operations Manual
Interface Schematic
37 POWER GROUND
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1
LIGHT DIM
ICS BUSS
CENTER PASSENGER HEADPHONE AUDIO
RIGHT PASSENGER HEADPHONE AUDIO
LEFT PASSENGER HEADPHONE AUDIO
CENTER PASSENGER KEY
RIGHT PASSENGER KEY
LEFT PASSENGER KEY
CENTER PASSENGER MIC
RIGHT PASSENGER MIC
SPARE AUDIO IN
LEFT PASSENGER MIC
SHIELDED GROUND
PA KEY
PA MIC HI
INPUT 4 AUDIO
INPUT 4 KEY
INPUT 4 MIC HI HT1
INPUT 3 AUDIO
INPUT 3 KEY
INPUT 3 MIC HI FM2
INPUT 2 AUDIO
INPUT 2 KEY
INPUT 2 MIC HI FM1
INPUT 1 AUDIO
INPUT 1 KEY
INPUT 1 MIC HI COM1
RIGHT HEADPHONE AUDIO
RIGHT ICS KEY
RIGHT TRANSMIT KEY
RIGHT MICROPHONE HI
LEFT HEADPHONE AUDIO
LEFT ICS KEY
LEFT TRANSMIT KEY
LEFT MICROPHONE HI
14 OR 28VDC POWER IN
ACS 300A
AUDIO PANEL
25
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NC
NC
RIGHT AFT PASS KEY
LEFT AFT PASS KEY
NC
NC
CENTER AFT PASS HEADPHONE AUDIO
RIGHT AFT PASS HEADPHONE AUDIO
LEFT AFT PASS HEADPHONE AUDIO
INPUT 8 AUDIO HI
INPUT 7 AUDIO HI
INPUT 6 AUDIO HI
SHIELDED GROUND
NC
LEFT AFT PASS ICS KEY
RIGHT AFT PASS ICS KEY
CENTER AFT PASS ICS KEY
NC
LEFT AFT PASS MIC HI
RIGHT AFT PASS MIC HI
CENTER AFT PASS MIC HI
INPUT 5 MIC HI
INPUT 5 KEY
INPUT 5 AUDIO HI
ONLY USED WITH SIX (6)
PASSENGER ICS OPTION
(INTERNAL MODULE)
NOT USED

Air Comm Systems, Inc. Page 6
ACS 300A-101 Installation and Operations Manual
Front Panel Controls
( See Figure 1 — Page 8 for pictorial )
nDescription
The ACS 300A Dual Audio Mixer Panel is a compact, lightweight unit which provides full audio control
and ICS support for Pilot and Co-pilot or observer positions in the aircraft. It has the capability to
provide each user with 5 receive audio selections, 6 transmitter selections, Normal and HOT (Hands
Free) ICS, and full headphone audio and ICS volume control. In addition, an internal expansion slot
excepts a plug-in module (optional) which can give the unit an additional 6 positions of ICS capability, 2
of which also have TX capability.
n1- Norm - Emer Switch
This switch controls the operation of the audio panel in the event of an audio amplifier failure. In the
“up” position (NORM) the audio panel is in normal operating mode. In the “down” position (EMER) the
unit is in the emergency mode. During Emergency operation,with a receive audio switch in the"down"
position the mic select rotary switch selects the mic, key, and unamplified audio in the event of an
audio amplifier failure. The side in emergency mode will not have incoming ICS.
n2 - Receive Audio Select-Mute Switches
Normal operation - In the “up” position the audio selected is summed with any other audios selected
into the headphone amplifier. It also selects or mutes cross sidetone. In the “down” position the audio
selected is muted. Cross sidetone is also muted.
Emergency operation - In the"down" position the mic select rotary switch selects the mic, key, and
unamplified audio in the event of an audio amplifier failure. The side in emergency mode will not have
incoming ICS.
n3 - Volume Controls
These concentric knobs adjust headphone volume. The larger one adjusts the radio volume while the
smaller one adjusts the intercom (ICS) volume. Clockwise rotation increases the volume - counter
clockwise rotation decreases the volume. To set volume, transmit on the radio and set the sidetone
level slightly on the low side so you will have a tendency to talk up and have higher modulation. Then
set the radio volume for comfortable listening. In the event of excessive or inadequate receiver volume
the pots located on the rear of the unit may be adjusted for the proper level. (see Figure 2 on page 8)
n4 - Lighting
The audio panel is lit by NVG lamps filters which provide night time visibility for all panel legends.
They can be connected to a dimmer bus for adjustment.

Air Comm Systems, Inc. Page 7
n5 - Mic Selector
This rotary switch performs three functions simultaneously. It (a) connects the mic to the selected
transmitter (b) selects the associated keyline, and (c) selects the associated audio (if not already
selected using the audio select-mute switch). The audio selected also allows for cross sidetone if the
other mic select switch has selected the same transmitter.
n6 - Transmit Indicator
When the transmit key is activated this NVG indicator lights up show that the audio panel is in the
transmit mode.
n7 - ICS Switch
This switch selects the ICS mode. In the “up” position (ICS) each side of the audio panel is connected
to the common ICS bus. This enables each side to communicate with the other side when their
respective ICS PTT switches are keyed.
In the “center” position (OFF), the ICS bus is disconnected and both sides are isolated.
The ICS switch also provides for “Hands Free” operation. In the “down” position (HOT ICS) , both
headphone mics are active and signals are fed into the ICS bus without having to key the respective
ICS PTT switches.
ACS 300A-101 Installation and Operations
Manual Front Panel Controls
( See Figure 1 — Page 8 for pictorial )
n8 - VOX POT
The high-power VOX is controlled by this knob. In order to use the VOX feature, the ICS ON/OFF/PVT
toggle switch must either be in the “ON” or “PVT” position. If the toggle switch is in the “OFF” position, the
Audio Mixer Panel is isolated from the ICS buss, and no ICS communication is possible. Once the ICS
switch is in the “ON” or “PVT” position, the VOX can be activated by turning the knob clockwise past the
On/Off detent and threshold set to activate with voice.
The moment you begin talking the VOX circuitry activates and relays your voice transmission. When you
stop speaking the VOX circuit turns off to reduce unwanted background noise. Turning the knob clockwise
adjusts the threshold. If the knob is turned fully clockwise the VOX circuit will always be active and you will
hear background noise. If the knob is adjusted just past the On/Off detent then the VOX circuit cannot be
activated and you will revert to normal keyed ICS. Adjust the threshold level to match the ambient noise
conditions of the aircraft at the time for proper operation.
While in the VOX mode, if you wish to quickly isolate yourself from the ICS buss, you simply put the ICS
ON/OFF/PVT toggle switch in the “OFF” position.

Air Comm Systems, Inc. Page 8
nFigure 1 - Front Panel Controls
nFigure 2 - Rear Panel Adjustment
ACS 300A-101 Installation and Operations Manual
Front and Rear Panel Controls
8
4
1
2
2
35
6
753
VFH1 VFH2 FM1 FM2 AUXFM

Air Comm Systems, Inc. Page 9
ACS 300A-101 Installation and Operations Manual
Instruction for Continued Airworthines
nGENERAL DESCRIPTION:
The Audio Mixer Panel consists of a Dzus mounting located in the cockpit or cabin area which provides
access to multiple radios for transmitting and receiving. It also provides intercom, both keyed and VOX
between other audio mixer panels or slave units located elsewhere in the aircraft.
nPURPOSE:
To provide instructions for the maintenance and inspection of the Air Comm Systems, Inc. Model ACS-300
Series Audio Mixer Panels.
This Manual provides instructions supplementing the aircraft maintenance manual. These instructions only
supersede the aircraft manual in the indicated areas.
nOPERATIONAL CHECK:
The Audio Mixer Panel should be checked prior to first flight each day per current operations manual.
nMAINTENANCE:
Check security and condition of Dzus mounted panel(s), check associated wiring hareness at periodic
inspections such as annual/100 hour IAW FAR43 Appendix D(i).
nOn Condition.
Send Audio Mixer Panel(s) to qualified repair facility for any repairs. Contact Air Comm
Systems, Inc. Phone [phone] or FAX [phone] for nearest factory authorized
repair facility.

Air Comm Systems, Inc. Page 10
nWarranty Information
ACS 300A-101 Installation and Operations Manual
Warranty Information
Air Comm Systems, Inc. warrants each new product to be free from defective material and workmanship
and agrees to remedy any defect or to furnish a new part in exchange for any defective unit provided an
examination discloses such defect occurred under normal use and service, and provided the defective unit
is delivered to us, with transportation charges prepaid, within 1 year from the date of acceptance of
equipment by the owner. Each unit required and claimed defective must be returned to:
This warranty does not extend to any products which have been subjected to misuse, neglect, accident, or
in violation of instructions furnished, nor does it extend to units which have been repaired or altered
outside of our factory except where such repairs are specifically authorized in writing by us.This warranty
is in lieu of all other warranties expressed or implied, and no representative or person is authorized to
assume for us any other liability in connection with the sale of our products.
Air Comm Systems, Inc.
37610 Sky Canyon Dr., Hangar 51
Murrieta, CA 92563
Ph: 951-677-0101
Fx: 951-677-0701
[email protected]